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Gupta B, Saxena A, Perillo ML, Wade-Kleyn LC, Thompson CH, Purcell EK. Structural, Functional, and Genetic Changes Surrounding Electrodes Implanted in the Brain. Acc Chem Res 2024; 57:1346-1359. [PMID: 38630432 PMCID: PMC11079975 DOI: 10.1021/acs.accounts.4c00057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/09/2024] [Accepted: 04/09/2024] [Indexed: 05/08/2024]
Abstract
ConspectusImplantable neurotechnology enables monitoring and stimulating of the brain signals responsible for performing cognitive, motor, and sensory tasks. Electrode arrays implanted in the brain are increasingly used in the clinic to treat a variety of sources of neurological diseases and injuries. However, the implantation of a foreign body typically initiates a tissue response characterized by physical disruption of vasculature and the neuropil as well as the initiation of inflammation and the induction of reactive glial states. Likewise, electrical stimulation can induce damage to the surrounding tissue depending on the intensity and waveform parameters of the applied stimulus. These phenomena, in turn, are likely influenced by the surface chemistry and characteristics of the materials employed, but further information is needed to effectively link the biological responses observed to specific aspects of device design. In order to inform improved design of implantable neurotechnology, we are investigating the basic science principles governing device-tissue integration. We are employing multiple techniques to characterize the structural, functional, and genetic changes that occur in the cells surrounding implanted electrodes. First, we have developed a new "device-in-slice" technique to capture chronically implanted electrodes within thick slices of live rat brain tissue for interrogation with single-cell electrophysiology and two-photon imaging techniques. Our data revealed several new observations of tissue remodeling surrounding devices: (a) there was significant disruption of dendritic arbors in neurons near implants, where losses were driven asymmetrically on the implant-facing side. (b) There was a significant loss of dendritic spine densities in neurons near implants, with a shift toward more immature (nonfunctional) morphologies. (c) There was a reduction in excitatory neurotransmission surrounding implants, as evidenced by a reduction in the frequency of excitatory postsynaptic currents (EPSCs). Lastly, (d) there were changes in the electrophysiological underpinnings of neuronal spiking regularity. In parallel, we initiated new studies to explore changes in gene expression surrounding devices through spatial transcriptomics, which we applied to both recording and stimulating arrays. We found that (a) device implantation is associated with the induction of hundreds of genes associated with neuroinflammation, glial reactivity, oligodendrocyte function, and cellular metabolism and (b) electrical stimulation induces gene expression associated with damage or plasticity in a manner dependent upon the intensity of the applied stimulus. We are currently developing computational analysis tools to distill biomarkers of device-tissue interactions from large transcriptomics data sets. These results improve the current understanding of the biological response to electrodes implanted in the brain while producing new biomarkers for benchmarking the effects of novel electrode designs on responses. As the next generation of neurotechnology is developed, it will be increasingly important to understand the influence of novel materials, surface chemistries, and implant architectures on device performance as well as the relationship with the induction of specific cellular signaling pathways.
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Affiliation(s)
- Bhavna Gupta
- Neuroscience
Program, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Akash Saxena
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Department
of Electrical and Computer Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Mason L. Perillo
- Department
of Biomedical Engineering, Michigan State
University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Lauren C. Wade-Kleyn
- Department
of Biomedical Engineering, Michigan State
University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Cort H. Thompson
- Department
of Biomedical Engineering, Michigan State
University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Erin K. Purcell
- Department
of Biomedical Engineering, Michigan State
University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Neuroscience
Program, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Department
of Electrical and Computer Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
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Suematsu N, Vazquez AL, Kozai TDY. Activation and depression of neural and hemodynamic responses induced by the intracortical microstimulation and visual stimulation in the mouse visual cortex. J Neural Eng 2024; 21:026033. [PMID: 38537268 PMCID: PMC11002944 DOI: 10.1088/1741-2552/ad3853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/28/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
Objective. Intracortical microstimulation (ICMS) can be an effective method for restoring sensory perception in contemporary brain-machine interfaces. However, the mechanisms underlying better control of neuronal responses remain poorly understood, as well as the relationship between neuronal activity and other concomitant phenomena occurring around the stimulation site.Approach. Different microstimulation frequencies were investigatedin vivoon Thy1-GCaMP6s mice using widefield and two-photon imaging to evaluate the evoked excitatory neural responses across multiple spatial scales as well as the induced hemodynamic responses. Specifically, we quantified stimulation-induced neuronal activation and depression in the mouse visual cortex and measured hemodynamic oxyhemoglobin and deoxyhemoglobin signals using mesoscopic-scale widefield imaging.Main results. Our calcium imaging findings revealed a preference for lower-frequency stimulation in driving stronger neuronal activation. A depressive response following the neural activation preferred a slightly higher frequency stimulation compared to the activation. Hemodynamic signals exhibited a comparable spatial spread to neural calcium signals. Oxyhemoglobin concentration around the stimulation site remained elevated during the post-activation (depression) period. Somatic and neuropil calcium responses measured by two-photon microscopy showed similar dependence on stimulation parameters, although the magnitudes measured in soma was greater than in neuropil. Furthermore, higher-frequency stimulation induced a more pronounced activation in soma compared to neuropil, while depression was predominantly induced in soma irrespective of stimulation frequencies.Significance. These results suggest that the mechanism underlying depression differs from activation, requiring ample oxygen supply, and affecting neurons. Our findings provide a novel understanding of evoked excitatory neuronal activity induced by ICMS and offer insights into neuro-devices that utilize both activation and depression phenomena to achieve desired neural responses.
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Affiliation(s)
- Naofumi Suematsu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Alberto L Vazquez
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, United States of America
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, United States of America
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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McNamara IN, Wellman SM, Li L, Eles JR, Savya S, Sohal HS, Angle MR, Kozai TDY. Electrode sharpness and insertion speed reduce tissue damage near high-density penetrating arrays. J Neural Eng 2024; 21:026030. [PMID: 38518365 DOI: 10.1088/1741-2552/ad36e1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
Objective. Over the past decade, neural electrodes have played a crucial role in bridging biological tissues with electronic and robotic devices. This study focuses on evaluating the optimal tip profile and insertion speed for effectively implanting Paradromics' high-density fine microwire arrays (FμA) prototypes into the primary visual cortex (V1) of mice and rats, addressing the challenges associated with the 'bed-of-nails' effect and tissue dimpling.Approach. Tissue response was assessed by investigating the impact of electrodes on the blood-brain barrier (BBB) and cellular damage, with a specific emphasis on tailored insertion strategies to minimize tissue disruption during electrode implantation.Main results.Electro-sharpened arrays demonstrated a marked reduction in cellular damage within 50μm of the electrode tip compared to blunt and angled arrays. Histological analysis revealed that slow insertion speeds led to greater BBB compromise than fast and pneumatic methods. Successful single-unit recordings validated the efficacy of the optimized electro-sharpened arrays in capturing neural activity.Significance.These findings underscore the critical role of tailored insertion strategies in minimizing tissue damage during electrode implantation, highlighting the suitability of electro-sharpened arrays for long-term implant applications. This research contributes to a deeper understanding of the complexities associated with high-channel-count microelectrode array implantation, emphasizing the importance of meticulous assessment and optimization of key parameters for effective integration and minimal tissue disruption. By elucidating the interplay between insertion parameters and tissue response, our study lays a strong foundation for the development of advanced implantable devices with a reduction in reactive gliosis and improved performance in neural recording applications.
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Affiliation(s)
- Ingrid N McNamara
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Lehong Li
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Sajishnu Savya
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | | | | | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center of the Basis of Neural Cognition, Pittsburgh, PA, United States of America
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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Ahmed S, Momin M, Ren J, Lee H, Zhou T. Self-Assembly Enabled Printable Asymmetric Self-Insulated Stretchable Conductor for Human Interface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2400082. [PMID: 38563579 DOI: 10.1002/adma.202400082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/11/2024] [Indexed: 04/04/2024]
Abstract
Soft and stretchable conductors with high electrical conductivity and tissue-like mechanical properties are crucial for both on-skin and implantable electronic devices. Liquid metal-based conductors hold great promise due to their metallic conductivity and minimal stiffness. However, the surface oxidation of liquid metal particles in polymeric matrices poses a challenge in forming a continuous pathway for highly conductive elastic composites. Here, it is reported a printable composite material based on liquid metal and conducting polymer that undergoes a self-assembly process, achieving high conductivity (2089 S cm-1) in the bottom surface while maintaining an insulated top surface, high stretchability (>800%), and a modulus akin to human skin tissue. This material is further applied to fabricate skin-interfaced strain sensors and electromyogram sensors through 3D printing.
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Affiliation(s)
- Salahuddin Ahmed
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Marzia Momin
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Jiashu Ren
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Hyunjin Lee
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Tao Zhou
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
- Center for Neural Engineering, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
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González-González MA, Conde SV, Latorre R, Thébault SC, Pratelli M, Spitzer NC, Verkhratsky A, Tremblay MÈ, Akcora CG, Hernández-Reynoso AG, Ecker M, Coates J, Vincent KL, Ma B. Bioelectronic Medicine: a multidisciplinary roadmap from biophysics to precision therapies. Front Integr Neurosci 2024; 18:1321872. [PMID: 38440417 PMCID: PMC10911101 DOI: 10.3389/fnint.2024.1321872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/10/2024] [Indexed: 03/06/2024] Open
Abstract
Bioelectronic Medicine stands as an emerging field that rapidly evolves and offers distinctive clinical benefits, alongside unique challenges. It consists of the modulation of the nervous system by precise delivery of electrical current for the treatment of clinical conditions, such as post-stroke movement recovery or drug-resistant disorders. The unquestionable clinical impact of Bioelectronic Medicine is underscored by the successful translation to humans in the last decades, and the long list of preclinical studies. Given the emergency of accelerating the progress in new neuromodulation treatments (i.e., drug-resistant hypertension, autoimmune and degenerative diseases), collaboration between multiple fields is imperative. This work intends to foster multidisciplinary work and bring together different fields to provide the fundamental basis underlying Bioelectronic Medicine. In this review we will go from the biophysics of the cell membrane, which we consider the inner core of neuromodulation, to patient care. We will discuss the recently discovered mechanism of neurotransmission switching and how it will impact neuromodulation design, and we will provide an update on neuronal and glial basis in health and disease. The advances in biomedical technology have facilitated the collection of large amounts of data, thereby introducing new challenges in data analysis. We will discuss the current approaches and challenges in high throughput data analysis, encompassing big data, networks, artificial intelligence, and internet of things. Emphasis will be placed on understanding the electrochemical properties of neural interfaces, along with the integration of biocompatible and reliable materials and compliance with biomedical regulations for translational applications. Preclinical validation is foundational to the translational process, and we will discuss the critical aspects of such animal studies. Finally, we will focus on the patient point-of-care and challenges in neuromodulation as the ultimate goal of bioelectronic medicine. This review is a call to scientists from different fields to work together with a common endeavor: accelerate the decoding and modulation of the nervous system in a new era of therapeutic possibilities.
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Affiliation(s)
- María Alejandra González-González
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, United States
- Department of Pediatric Neurology, Baylor College of Medicine, Houston, TX, United States
| | - Silvia V. Conde
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NOVA University, Lisbon, Portugal
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Stéphanie C. Thébault
- Laboratorio de Investigación Traslacional en salud visual (D-13), Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, Mexico
| | - Marta Pratelli
- Neurobiology Department, Kavli Institute for Brain and Mind, UC San Diego, La Jolla, CA, United States
| | - Nicholas C. Spitzer
- Neurobiology Department, Kavli Institute for Brain and Mind, UC San Diego, La Jolla, CA, United States
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China
- International Collaborative Center on Big Science Plan for Purinergic Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| | - Cuneyt G. Akcora
- Department of Computer Science, University of Central Florida, Orlando, FL, United States
| | | | - Melanie Ecker
- Department of Biomedical Engineering, University of North Texas, Denton, TX, United States
| | | | - Kathleen L. Vincent
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX, United States
| | - Brandy Ma
- Stanley H. Appel Department of Neurology, Houston Methodist Hospital, Houston, TX, United States
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Suematsu N, Vazquez AL, Kozai TD. Activation and depression of neural and hemodynamic responses induced by the intracortical microstimulation and visual stimulation in the mouse visual cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.01.573814. [PMID: 38260671 PMCID: PMC10802282 DOI: 10.1101/2024.01.01.573814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Objective . Intracortical microstimulation can be an effective method for restoring sensory perception in contemporary brain-machine interfaces. However, the mechanisms underlying better control of neuronal responses remain poorly understood, as well as the relationship between neuronal activity and other concomitant phenomena occurring around the stimulation site. Approach . Different microstimulation frequencies were investigated in vivo on Thy1-GCaMP6s mice using widefield and two-photon imaging to evaluate the evoked excitatory neural responses across multiple spatial scales as well as the induced hemodynamic responses. Specifically, we quantified stimulation-induced neuronal activation and depression in the mouse visual cortex and measured hemodynamic oxyhemoglobin and deoxyhemoglobin signals using mesoscopic-scale widefield imaging. Main results . Our calcium imaging findings revealed a preference for lower-frequency stimulation in driving stronger neuronal activation. A depressive response following the neural activation preferred a slightly higher frequency stimulation compared to the activation. Hemodynamic signals exhibited a comparable spatial spread to neural calcium signals. Oxyhemoglobin concentration around the stimulation site remained elevated during the post-activation (depression) period. Somatic and neuropil calcium responses measured by two-photon microscopy showed similar dependence on stimulation parameters, although the magnitudes measured in soma was greater than in neuropil. Furthermore, higher-frequency stimulation induced a more pronounced activation in soma compared to neuropil, while depression was predominantly induced in soma irrespective of stimulation frequencies. Significance . These results suggest that the mechanism underlying depression differs from activation, requiring ample oxygen supply, and affecting neurons. Our findings provide a novel understanding of evoked excitatory neuronal activity induced by intracortical microstimulation and offer insights into neuro-devices that utilize both activation and depression phenomena to achieve desired neural responses.
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Hernandez-Reynoso AG, Sturgill BS, Hoeferlin GF, Druschel LN, Krebs OK, Menendez DM, Thai TTD, Smith TJ, Duncan J, Zhang J, Mittal G, Radhakrishna R, Desai MS, Cogan SF, Pancrazio JJ, Capadona JR. The effect of a Mn(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP) coating on the chronic recording performance of planar silicon intracortical microelectrode arrays. Biomaterials 2023; 303:122351. [PMID: 37931456 PMCID: PMC10842897 DOI: 10.1016/j.biomaterials.2023.122351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/27/2023] [Accepted: 10/11/2023] [Indexed: 11/08/2023]
Abstract
Intracortical microelectrode arrays (MEAs) are used to record neural activity. However, their implantation initiates a neuroinflammatory cascade, involving the accumulation of reactive oxygen species, leading to interface failure. Here, we coated commercially-available MEAs with Mn(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP), to mitigate oxidative stress. First, we assessed the in vitro cytotoxicity of modified sample substrates. Then, we implanted 36 rats with uncoated, MnTBAP-coated ("Coated"), or (3-Aminopropyl)triethoxysilane (APTES)-coated devices - an intermediate step in the coating process. We assessed electrode performance during the acute (1-5 weeks), sub-chronic (6-11 weeks), and chronic (12-16 weeks) phases after implantation. Three subsets of animals were euthanized at different time points to assess the acute, sub-chronic and chronic immunohistological responses. Results showed that MnTBAP coatings were not cytotoxic in vitro, and their implantation in vivo improved the proportion of electrodes during the sub-chronic and chronic phases; APTES coatings resulted in failure of the neural interface during the chronic phase. In addition, MnTBAP coatings improved the quality of the signal throughout the study and reduced the neuroinflammatory response around the implant as early as two weeks, an effect that remained consistent for months post-implantation. Together, these results suggest that MnTBAP coatings are a potentially useful modification to improve MEA reliability.
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Affiliation(s)
- Ana G Hernandez-Reynoso
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Brandon S Sturgill
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - George F Hoeferlin
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Lindsey N Druschel
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Olivia K Krebs
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Dhariyat M Menendez
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Teresa T D Thai
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Thomas J Smith
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Jonathan Duncan
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Jichu Zhang
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Gaurav Mittal
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Rahul Radhakrishna
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Mrudang Spandan Desai
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Stuart F Cogan
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
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Wu GK, Ardeshirpour Y, Mastracchio C, Kent J, Caiola M, Ye M. Amplitude- and frequency-dependent activation of layer II/III neurons by intracortical microstimulation. iScience 2023; 26:108140. [PMID: 37915592 PMCID: PMC10616374 DOI: 10.1016/j.isci.2023.108140] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/27/2023] [Accepted: 10/02/2023] [Indexed: 11/03/2023] Open
Abstract
Intracortical microstimulation (ICMS) has been used for the development of brain machine interfaces. However, further understanding about the spatiotemporal responses of neurons to different electrical stimulation parameters is necessary to inform the design of optimal therapies. In this study, we employed in vivo electrophysiological recording, two-photon calcium imaging, and electric field simulation to evaluate the acute effect of ICMS on layer II/III neurons. Our results show that stimulation frequency non-linearly modulates neuronal responses, whereas the magnitude of responses is linearly correlated to the electric field strength and stimulation amplitude before reaching a steady state. Temporal dynamics of neurons' responses depends more on stimulation frequency and their distance to the stimulation electrode. In addition, amplitude-dependent post-stimulation suppression was observed within ∼500 μm of the stimulation electrode, as evidenced by both calcium imaging and local field potentials. These findings provide insights for selecting stimulation parameters to achieve desirable spatiotemporal specificity of ICMS.
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Affiliation(s)
- Guangying K. Wu
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Yasaman Ardeshirpour
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Christina Mastracchio
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Jordan Kent
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
- Scientific Publications Department, Society for Neuroscience, Washington DC, USA
| | - Michael Caiola
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Meijun Ye
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
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Chen K, Forrest A, Gonzalez Burgos G, Kozai TDY. Neuronal functional connectivity is impaired in a layer dependent manner near the chronically implanted microelectrodes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.06.565852. [PMID: 37986883 PMCID: PMC10659303 DOI: 10.1101/2023.11.06.565852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Objective This study aims to reveal longitudinal changes in functional network connectivity within and across different brain structures near the chronically implanted microelectrode. While it is well established that the foreign-body response (FBR) contributes to the gradual decline of the signals recorded from brain implants over time, how does the FBR impact affect the functional stability of neural circuits near implanted Brain-Computer Interfaces (BCIs) remains unknown. This research aims to illuminate how the chronic FBR can alter local neural circuit function and the implications for BCI decoders. Approach This study utilized multisite Michigan-style microelectrodes that span all cortical layers and the hippocampal CA1 region to collect spontaneous and visually-evoked electrophysiological activity. Alterations in neuronal activity near the microelectrode were tested assessing cross-frequency synchronization of LFP and spike entrainment to LFP oscillatory activity throughout 16 weeks after microelectrode implantation. Main Results The study found that cortical layer 4, the input-receiving layer, maintained activity over the implantation time. However, layers 2/3 rapidly experienced severe impairment, leading to a loss of proper intralaminar connectivity in the downstream output layers 5/6. Furthermore, the impairment of interlaminar connectivity near the microelectrode was unidirectional, showing decreased connectivity from Layers 2/3 to Layers 5/6 but not the reverse direction. In the hippocampus, CA1 neurons gradually became unable to properly entrain to the surrounding LFP oscillations. Significance This study provides a detailed characterization of network connectivity dysfunction over long-term microelectrode implantation periods. This new knowledge could contribute to the development of targeted therapeutic strategies aimed at improving the health of the tissue surrounding brain implants and potentially inform engineering of adaptive decoders as the FBR progresses. Our study's understanding of the dynamic changes in the functional network over time opens the door to developing interventions for improving the long-term stability and performance of intracortical microelectrodes.
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10
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Scholten K, Xu H, Lu Z, Jiang W, Ortigoza-Diaz J, Petrossians A, Orler S, Gallonio R, Liu X, Song D, Meng E. Polymer Implantable Electrode Foundry: A shared resource for manufacturing polymer-based microelectrodes for neural interfaces. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.05.565048. [PMID: 37986740 PMCID: PMC10659271 DOI: 10.1101/2023.11.05.565048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Large scale monitoring of neural activity at the single unit level can be achieved via electrophysiological recording using implanted microelectrodes. While neuroscience researchers have widely employed chronically implanted electrode-based interfaces for this purpose, a commonly encountered limitation is loss of highly resolved signals arising from immunological response over time. Next generation electrode-based interfaces improve longitudinal signal quality using the strategy of stabilizing the device-tissue interface with microelectrode arrays constructed from soft and flexible polymer materials. The limited availability of such polymer microelectrode arrays has restricted access to a small number of researchers able to build their own custom devices or who have developed specific collaborations with engineering researchers who can produce them. Here, a new technology resource model is introduced that seeks to widely increase access to polymer microelectrode arrays by the neuroscience research community. The Polymer Implantable Electrode (PIE) Foundry provides custom and standardized polymer microelectrode arrays as well as training and guidance on best-practices for implantation and chronic experiments.
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Affiliation(s)
- Kee Scholten
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
| | - Huijing Xu
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
| | - Zhouxiao Lu
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
| | - Wenxuan Jiang
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
| | - Jessica Ortigoza-Diaz
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
| | - Artin Petrossians
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
| | - Steven Orler
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
| | - Rachael Gallonio
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
| | - Xin Liu
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
| | - Dong Song
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
- Neuroscience Graduate Program, University of Southern California, Los Angeles, USA
| | - Ellis Meng
- Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, USA
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11
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Murray DS, Stickel L, Boutelle M. Computational Modeling as a Tool to Drive the Development of a Novel, Chemical Device for Monitoring the Injured Brain and Body. ACS Chem Neurosci 2023; 14:3599-3608. [PMID: 37737666 PMCID: PMC10557062 DOI: 10.1021/acschemneuro.3c00063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 09/06/2023] [Indexed: 09/23/2023] Open
Abstract
Real-time measurement of dynamic changes, occurring in the brain and other parts of the body, is useful for the detection and tracked progression of disease and injury. Chemical monitoring of such phenomena exists but is not commonplace, due to the penetrative nature of devices, the lack of continuous measurement, and the inflammatory responses that require pharmacological treatment to alleviate. Soft, flexible devices that more closely match the moduli and shape of monitored tissue and allow for surface microdialysis provide a viable alternative. Here, we show that computational modeling can be used to aid the development of such devices and highlight the considerations when developing a chemical monitoring probe in this way. These models pave the way for the development of a new class of chemical monitoring devices for monitoring neurotrauma, organs, and skin.
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Affiliation(s)
- De-Shaine Murray
- Department
of Bioengineering, Imperial College London SW7 2AZ, London, U.K.
- School
of Engineering and Applied Sciences, Yale
University, 06520, New Haven, Connecticut United States
| | - Laure Stickel
- Department
of Bioengineering, Imperial College London SW7 2AZ, London, U.K.
- Laboratoire
Physico-Chimie Curie, Institut Curie, 26 rue d’Ulm, 75005, Paris, France
| | - Martyn Boutelle
- Department
of Bioengineering, Imperial College London SW7 2AZ, London, U.K.
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12
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Gregory BA, Thompson CH, Salatino JW, Railing MJ, Zimmerman AF, Gupta B, Williams K, Beatty JA, Cox CL, Purcell EK. Structural and functional changes of deep layer pyramidal neurons surrounding microelectrode arrays implanted in rat motor cortex. Acta Biomater 2023; 168:429-439. [PMID: 37499727 PMCID: PMC10441615 DOI: 10.1016/j.actbio.2023.07.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/25/2023] [Accepted: 07/18/2023] [Indexed: 07/29/2023]
Abstract
Devices capable of recording or stimulating neuronal signals have created new opportunities to understand normal physiology and treat sources of pathology in the brain. However, it is possible that the tissue response to implanted electrodes may influence the nature of the signals detected or stimulated. In this study, we characterized structural and functional changes in deep layer pyramidal neurons surrounding silicon or polyimide-based electrodes implanted in the motor cortex of rats. Devices were captured in 300 µm-thick tissue slices collected at the 1 or 6 week time point post-implantation, and individual neurons were assessed using a combination of whole-cell electrophysiology and 2-photon imaging. We observed disrupted dendritic arbors and a significant reduction in spine densities in neurons surrounding devices. These effects were accompanied by a decrease in the frequency of spontaneous excitatory post-synaptic currents, a reduction in sag amplitude, an increase in spike frequency adaptation, and an increase in filopodia density. We hypothesize that the effects observed in this study may contribute to the signal loss and instability that often accompany chronically implanted electrodes. STATEMENT OF SIGNIFICANCE: Implanted electrodes in the brain can be used to treat sources of pathology and understand normal physiology by recording or stimulating electrical signals generated by local neurons. However, a foreign body response following implantation undermines the performance of these devices. While several studies have investigated the biological mechanisms of device-tissue interactions through histology, transcriptomics, and imaging, our study is the first to directly interrogate effects on the function of neurons surrounding electrodes using single-cell electrophysiology. Additionally, we provide new, detailed assessments of the impacts of electrodes on the dendritic structure and spine morphology of neurons, and we assess effects for both traditional (silicon) and newer polymer electrode materials. These results reveal new potential mechanisms of electrode-tissue interactions.
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Affiliation(s)
| | - Cort H Thompson
- Department of Biomedical Engineering, Michigan State University, United States
| | - Joseph W Salatino
- Department of Biomedical Engineering, Michigan State University, United States
| | - Mia J Railing
- Department of Physiology, Michigan State University, United States
| | | | - Bhavna Gupta
- Neuroscience Program, Michigan State University, United States
| | - Kathleen Williams
- Department of Biomedical Engineering, Michigan State University, United States
| | - Joseph A Beatty
- Department of Physiology, Michigan State University, United States; Neuroscience Program, Michigan State University, United States
| | - Charles L Cox
- Department of Physiology, Michigan State University, United States; Neuroscience Program, Michigan State University, United States
| | - Erin K Purcell
- Department of Biomedical Engineering, Michigan State University, United States; Neuroscience Program, Michigan State University, United States; Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, United States.
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13
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Osanai H, Yamamoto J, Kitamura T. Extracting electromyographic signals from multi-channel LFPs using independent component analysis without direct muscular recording. CELL REPORTS METHODS 2023; 3:100482. [PMID: 37426755 PMCID: PMC10326347 DOI: 10.1016/j.crmeth.2023.100482] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/12/2023] [Accepted: 04/25/2023] [Indexed: 07/11/2023]
Abstract
Electromyography (EMG) has been commonly used for the precise identification of animal behavior. However, it is often not recorded together with in vivo electrophysiology due to the need for additional surgeries and setups and the high risk of mechanical wire disconnection. While independent component analysis (ICA) has been used to reduce noise from field potential data, there has been no attempt to proactively use the removed "noise," of which EMG signals are thought to be one of the major sources. Here, we demonstrate that EMG signals can be reconstructed without direct EMG recording using the "noise" ICA component from local field potentials. The extracted component is highly correlated with directly measured EMG, termed IC-EMG. IC-EMG is useful for measuring an animal's sleep/wake, freezing response, and non-rapid eye movement (NREM)/REM sleep states consistently with actual EMG. Our method has advantages in precise and long-term behavioral measurement in wide-ranging in vivo electrophysiology experiments.
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Affiliation(s)
- Hisayuki Osanai
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jun Yamamoto
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Takashi Kitamura
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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14
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Luan L, Yin R, Zhu H, Xie C. Emerging Penetrating Neural Electrodes: In Pursuit of Large Scale and Longevity. Annu Rev Biomed Eng 2023; 25:185-205. [PMID: 37289556 PMCID: PMC11078330 DOI: 10.1146/annurev-bioeng-090622-050507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Penetrating neural electrodes provide a powerful approach to decipher brain circuitry by allowing for time-resolved electrical detections of individual action potentials. This unique capability has contributed tremendously to basic and translational neuroscience, enabling both fundamental understandings of brain functions and applications of human prosthetic devices that restore crucial sensations and movements. However, conventional approaches are limited by the scarce number of available sensing channels and compromised efficacy over long-term implantations. Recording longevity and scalability have become the most sought-after improvements in emerging technologies. In this review, we discuss the technological advances in the past 5-10 years that have enabled larger-scale, more detailed, and longer-lasting recordings of neural circuits at work than ever before. We present snapshots of the latest advances in penetration electrode technology, showcase their applications in animal models and humans, and outline the underlying design principles and considerations to fuel future technological development.
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Affiliation(s)
- Lan Luan
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
| | - Rongkang Yin
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
| | - Hanlin Zhu
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
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15
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Yuan T, Zhan W, Dini D. Linking fluid-axons interactions to the macroscopic fluid transport properties of the brain. Acta Biomater 2023; 160:152-163. [PMID: 36781040 DOI: 10.1016/j.actbio.2023.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/25/2023] [Accepted: 02/06/2023] [Indexed: 02/13/2023]
Abstract
Many brain disorders, including Alzheimer's Disease and Parkinson's Disease, and drug delivery procedures are linked to fluid transport in the brain; yet, while neurons are extremely soft and can be easily deformed, how the microscale channel flow interacts with the neuronal structures (especially axons) deformation and how these interactions affect the macroscale tissue function and transport properties is poorly understood. Misrepresenting these relationships may lead to the erroneous prediction of e.g. disease spread, drug delivery, and nerve injury in the brain. However, understanding fluid-neuron interactions is an outstanding challenge because the behaviours of both phases are not only dynamic but also occur at an extremely small length scale (the width of the flow channel is ∼100 nm), which cannot be captured by state-of-the-art experimental techniques. Here, by explicitly simulating the dynamics of the flow and axons at the microstructural level, we, for the first time, establish the link between micromechanical tissue response to the physical laws governing the macroscopic transport property of the brain white matter. We found that interactions between axons and the interstitial flow are very strong, thus playing an essential role in the brain fluid/mass transport. Furthermore, we proposed the first anisotropic pressure-dependent permeability tensor informed by microstructural dynamics for more accurate brain modelling at the macroscale, and analysed the effect of the variation of the microstructural parameters that influence such tensor. These findings will shed light on some unsolved issues linked to brain functions and medical treatments relying on intracerebral transport, and the mathematical model provides a framework to more realistically model the brain and design brain-tissue-like biomaterials. STATEMENT OF SIGNIFICANCE: This study reveals how neurons interact with the fluid flowing around them and how these microscale interactions affect macroscale transport behaviour of the brain tissue. The findings provide unprecedented insights into some unsolved issues linked to brain functions and medical treatments relying on intracerebral fluid transport. Furthermore, we, for the first time, established a microstructure-informed permeability tensor as a function of local hydraulic pressure and pressure gradient for the brain tissue, which inherently captures the dynamic transport property of the brain. This study is a cornerstone to advance the predicting accuracy of brain tissue transport property and neural tissue engineering.
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Affiliation(s)
- Tian Yuan
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK.
| | - Wenbo Zhan
- School of Engineering, King's College, University of Aberdeen, Aberdeen, AB24 3UE, UK
| | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK.
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16
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Sharon A, Jankowski MM, Shmoel N, Erez H, Spira ME. Significantly reduced inflammatory foreign-body-response to neuroimplants and improved recording performance in young compared to adult rats. Acta Biomater 2023; 158:292-307. [PMID: 36632879 DOI: 10.1016/j.actbio.2023.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/29/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023]
Abstract
The multicellular inflammatory encapsulation of implanted intracortical multielectrode arrays (MEA) is associated with severe deterioration of their field potentials' (FP) recording performance, which thus limits the use of brain implants in basic research and clinical applications. Therefore, extensive efforts have been made to identify the conditions in which the inflammatory foreign body response (FBR) is alleviated, or to develop methods to mitigate the formation of the inflammatory barrier. Here, for the first time, we show that (1) in young rats (74±8 gr, 4 weeks old at the onset of the experiments), cortical tissue recovery following MEA implantation proceeds with ameliorated inflammatory scar as compared to adult rats (242 ± 18 gr, 9 weeks old at the experimental onset); (2) in contrast to adult rats in which the Colony Stimulating factor 1 Receptor (CSF1R) antagonist chow eliminated ∼95% of the cortical microglia but not microglia adhering to the implant surfaces, in young rats the microglia adhering to the implant were eliminated along with the parenchymal microglia population. The removal of microglia adhering to the implant surfaces was correlated with improved recording performance by in-house fabricated Perforated Polyimide MEA Platforms (PPMP). These results support the hypothesis that microglia adhering to the surface of the electrodes, rather than the multicellular inflammatory scar, is the major underlying mechanism that deteriorates implant recording performance, and that young rats provide an advantageous model to study months-long, multisite electrophysiology in freely behaving rats. STATEMENT OF SIGNIFICANCE: Multisite electrophysiological recordings and stimulation devices play central roles in basic brain research and medical applications. The insertion of multielectrode-array platforms into the brain's parenchyma unavoidably injures the tissue, and initiates a multicellular inflammatory cascade culminating in the formation of an encapsulating scar tissue (the foreign body response-FBR). The dominant view, which directs most current research efforts to mitigate the FBR, holds that the FBR is the major hurdle to effective electrophysiological use of neuroprobes. By contrast, this report demonstrates that microglia adhering to the surface of a neuroimplants, rather than the multicellular FBR, underlie the performance deterioration of neuroimplants. These findings pave the way to the development of novel and focused strategies to overcome the functional deterioration of neuroimplants.
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Affiliation(s)
- Aviv Sharon
- Department of Neurobiology, the Alexander Silberman Institute of Life Science, the Hebrew University of Jerusalem, Jerusalem, Israel; The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maciej M Jankowski
- Department of Neurobiology, the Alexander Silberman Institute of Life Science, the Hebrew University of Jerusalem, Jerusalem, Israel; The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, the Hebrew University of Jerusalem, Jerusalem, Israel; Edmond and Lily Safra Center for Brain Sciences, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nava Shmoel
- Department of Neurobiology, the Alexander Silberman Institute of Life Science, the Hebrew University of Jerusalem, Jerusalem, Israel; The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hadas Erez
- Department of Neurobiology, the Alexander Silberman Institute of Life Science, the Hebrew University of Jerusalem, Jerusalem, Israel; The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Micha E Spira
- Department of Neurobiology, the Alexander Silberman Institute of Life Science, the Hebrew University of Jerusalem, Jerusalem, Israel; The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, the Hebrew University of Jerusalem, Jerusalem, Israel.
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17
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Guljakow J, Lang W. Failure Reason of PI Test Samples of Neural Implants. SENSORS (BASEL, SWITZERLAND) 2023; 23:1340. [PMID: 36772377 PMCID: PMC9919689 DOI: 10.3390/s23031340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Samples that were meant to simulate the behavior of neural implants were put into Ringer's solution, and the occurring damage was assessed. The samples consist of an interdigitated gold-structure and two contact pads embedded between two Polyimide layers, resulting in free-floating structures. The two parts of the interdigitated structure have no electric contacts and are submerged in the solution during the experiment. The samples were held at temperatures of 37 and 57 ∘C in order to undergo an accelerated lifetime test and to compare the results. During the course of the experiment, a voltage was applied and measured over a resistance of 1 kOhm over time. Arduinos were used as measuring devices. As the intact samples are insulating, a sudden rise in voltage indicates a sample failure due to liquid leaking in between the two polyimide layers. Once a short-circuit occurred and a sample broke down, the samples were taken out of the vial and examined under a microscope. In virtually all cases, delamination was observable, with variation in the extent of the delaminated area. A comparison between measured voltages after failure and damage did not show a correlation between voltage and area affected by delamination. However, at a temperature of 37 ∘C, voltage remained constant most of the time after delamination, and a pin-hole lead to a lower measured voltage and strong fluctuations. Visually, no difference in damage between the 37 and the 57 ∘C samples was observed, although fluctuations of measured voltage occurred in numerous samples at a higher temperature. This difference hints at differences in the reasons for failure and thus limited applicability of accelerated lifetime tests.
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18
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Patel PR, Welle EJ, Letner JG, Shen H, Bullard AJ, Caldwell CM, Vega-Medina A, Richie JM, Thayer HE, Patil PG, Cai D, Chestek CA. Utah array characterization and histological analysis of a multi-year implant in non-human primate motor and sensory cortices. J Neural Eng 2023; 20:10.1088/1741-2552/acab86. [PMID: 36595323 PMCID: PMC9954796 DOI: 10.1088/1741-2552/acab86] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/14/2022] [Indexed: 12/15/2022]
Abstract
Objective.The Utah array is widely used in both clinical studies and neuroscience. It has a strong track record of safety. However, it is also known that implanted electrodes promote the formation of scar tissue in the immediate vicinity of the electrodes, which may negatively impact the ability to record neural waveforms. This scarring response has been primarily studied in rodents, which may have a very different response than primate brain.Approach.Here, we present a rare nonhuman primate histological dataset (n= 1 rhesus macaque) obtained 848 and 590 d after implantation in two brain hemispheres. For 2 of 4 arrays that remained within the cortex, NeuN was used to stain for neuron somata at three different depths along the shanks. Images were filtered and denoised, with neurons then counted in the vicinity of the arrays as well as a nearby section of control tissue. Additionally, 3 of 4 arrays were imaged with a scanning electrode microscope to evaluate any materials damage that might be present.Main results.Overall, we found a 63% percent reduction in the number of neurons surrounding the electrode shanks compared to control areas. In terms of materials, the arrays remained largely intact with metal and Parylene C present, though tip breakage and cracks were observed on many electrodes.Significance.Overall, these results suggest that the tissue response in the nonhuman primate brain shows similar neuron loss to previous studies using rodents. Electrode improvements, for example using smaller or softer probes, may therefore substantially improve the tissue response and potentially improve the neuronal recording yield in primate cortex.
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Affiliation(s)
- Paras R. Patel
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Elissa J. Welle
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Joseph G. Letner
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Hao Shen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Autumn J. Bullard
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Ciara M. Caldwell
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Alexis Vega-Medina
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019, United States of America,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America
| | - Julianna M. Richie
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Hope E. Thayer
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Parag G. Patil
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America,Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America,Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America
| | - Dawen Cai
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America,Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, United States of America,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48019, United States of America
| | - Cynthia A. Chestek
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America,Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, United States of America,Robotics Program, University of Michigan, Ann Arbor, MI 48109, United States of America, Corresponding author:
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19
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Savya SP, Li F, Lam S, Wellman SM, Stieger KC, Chen K, Eles JR, Kozai TDY. In vivo spatiotemporal dynamics of astrocyte reactivity following neural electrode implantation. Biomaterials 2022; 289:121784. [PMID: 36103781 PMCID: PMC10231871 DOI: 10.1016/j.biomaterials.2022.121784] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/24/2022] [Accepted: 08/29/2022] [Indexed: 11/02/2022]
Abstract
Brain computer interfaces (BCIs), including penetrating microelectrode arrays, enable both recording and stimulation of neural cells. However, device implantation inevitably causes injury to brain tissue and induces a foreign body response, leading to reduced recording performance and stimulation efficacy. Astrocytes in the healthy brain play multiple roles including regulating energy metabolism, homeostatic balance, transmission of neural signals, and neurovascular coupling. Following an insult to the brain, they are activated and gather around the site of injury. These reactive astrocytes have been regarded as one of the main contributors to the formation of a glial scar which affects the performance of microelectrode arrays. This study investigates the dynamics of astrocytes within the first 2 weeks after implantation of an intracortical microelectrode into the mouse brain using two-photon microscopy. From our observation astrocytes are highly dynamic during this period, exhibiting patterns of process extension, soma migration, morphological activation, and device encapsulation that are spatiotemporally distinct from other glial cells, such as microglia or oligodendrocyte precursor cells. This detailed characterization of astrocyte reactivity will help to better understand the tissue response to intracortical devices and lead to the development of more effective intervention strategies to improve the functional performance of neural interfacing technology.
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Affiliation(s)
- Sajishnu P Savya
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Northwestern University, USA
| | - Fan Li
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA; Computational Modeling & Simulation PhD Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephanie Lam
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kevin C Stieger
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Keying Chen
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA.
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20
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Liu X, Xu Z, Fu X, Liu Y, Jia H, Yang Z, Zhang J, Wei S, Duan X. Stable, long-term single-neuronal recording from the rat spinal cord with flexible carbon nanotube fiber electrodes. J Neural Eng 2022; 19. [DOI: 10.1088/1741-2552/ac9258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 09/15/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Objective. Flexible implantable electrodes enable months-long stable recording of single-unit signals from rat brains. Despite extensive efforts in the development of flexible probes for brain recording, thus far there are no conclusions on their application in long-term single neuronal recording from the spinal cord which is more mechanically active. To this end, we realized the chronic recording of single-unit signals from the spinal cord of freely-moving rats using flexible carbon nanotube fiber (CNTF) electrodes. Approach. We developed flexible CNTF electrodes for intraspinal recording. Continuous in vivo impedance monitoring and histology studies were conducted to explore the critical factors determining the longevity of the recording, as well as to illustrate the evolution of the electrode-tissue interface. Gait analysis were performed to evaluate the biosafety of the chronic intraspinal implantation of the CNTF electrodes. Main results. By increasing the insulation thickness of the CNTF electrodes, single-unit signals were continuously recorded from the spinal cord of freely-moving rats without electrode repositioning for 3-4 months. Single neuronal and local field potential activities in response to somatic mechanical stimulation were successfully recorded from the spinal dorsal horns. Histological data demonstrated the ability of the CNTF microelectrodes to form an improved intraspinal interfaces with greatly reduced gliosis compared to their stiff metal counterparts. Continuous impedance monitoring suggested that the longevity of the intraspinal recording with CNTF electrodes was determined by the insulation durability. Gait analysis showed that the chronic presence of the CNTF electrodes caused no noticeable locomotor deficits in rats. Significance. It was found that the chronic recording from the spinal cord faces more stringent requirements on the electrode structural durability than recording from the brain. The stable, long-term intraspinal recording provides unique capabilities for studying the physiological functions of the spinal cord relating to motor, sensation, and autonomic control in both health and disease.
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21
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Zheng XS, Yang Q, Vazquez A, Cui XT. Imaging the stability of chronic electrical microstimulation using electrodes coated with PEDOT/CNT and iridium oxide. iScience 2022; 25:104539. [PMID: 35769881 PMCID: PMC9234710 DOI: 10.1016/j.isci.2022.104539] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 03/22/2022] [Accepted: 06/01/2022] [Indexed: 11/23/2022] Open
Abstract
Chronic microstimulation is faced with challenges that require an additional understanding of stability and safety. We implanted silicon arrays coated with poly(3,4-ethylenedioxythiophene) (PEDOT)/Carbon Nanotubes (CNT), or PCand IrOx into the cortex of GCaMP6s mice and electrically stimulated them for up to 12 weeks. We quantified neuronal responses to stimulation using two-photon imaging and mesoscale fluorescence microscopy and characterized electrode performance over time. We observed dynamic changes in stimulation stability over time and a significant advantage in energy efficiency using PC coated electrodes over IrOx coated electrodes. In a subset of mice, we observed abnormal ictal cortical responses or cortical spreading depression using stimulation parameters commonly used in intracortical stimulation applications, suggesting the need to investigate the potential neuronal damage and redefine the stimulation safety limit. This study not only revealed the dynamic changes in stimulation efficiency after implantation but also reiterates the potential for PC as a high-efficiency material in chronic neuromodulation.
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Affiliation(s)
- Xin Sally Zheng
- Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Qianru Yang
- Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
- Center for Neural Basis of Cognition, 115 Mellon Institute, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | - Alberto Vazquez
- Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
- Center for Neural Basis of Cognition, 115 Mellon Institute, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
- Department of Radiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA 15213, USA
- McGowan Institute for Regenerative Medicine, 3025 East Carson Street, Pittsburgh, PA 15219, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
- Center for Neural Basis of Cognition, 115 Mellon Institute, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
- McGowan Institute for Regenerative Medicine, 3025 East Carson Street, Pittsburgh, PA 15219, USA
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22
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Yi J, Kim J, Baek C, Seo JM. Selective Edge Rounding of Cyclic Olefin Copolymer Film Using UV Laser for Implantable Electrode Package. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:4877-4879. [PMID: 36086311 DOI: 10.1109/embc48229.2022.9871196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Cyclic Olefin Copolymer is emerging as a packaging material for implantable electrodes due to its physical properties such as low water absorption rate and low water vapor permeability. The electrode-tissue interface is often regarded as a major focus of implantable electrodes, but its packaging should also be considered thoroughly since it directly contacts the adjoining body cells. Therefore, eliminating any sharp boundaries or edges around the package would be beneficial to minimize potential inflammatory responses caused by physical/mechanical stresses. To smooth both inner/outer edges of a cyclic olefin copolymer packaging, an optimal UV laser condition was investigated by varying its marking speed and iterations. Clinical relevance - This establishes a method that can selectively smooth the edges around a cyclic olefin copolymer pack-aged implantable electrodes for reduced mechanical mismatch after insertion.
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23
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Liu S, Liu L, Zhao Y, Wang Y, Wu Y, Zhang XD, Ming D. A High-Performance Electrode Based on van der Waals Heterostructure for Neural Recording. NANO LETTERS 2022; 22:4400-4409. [PMID: 35587781 DOI: 10.1021/acs.nanolett.2c00848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Neural electrodes have been widely used to monitor neurological disorders and have a major impact on neuroscience, whereas traditional electrodes are limited to their inherent high impedance, which makes them insensitive to weak signals during recording neural signals. Herein, we developed a neural electrode based on the graphene/Ag van der Waals heterostructure for improving the detection sensitivity and signal-to-noise ratio (SNR). The impedance of the graphene/Ag electrode is reduced to 161.4 ± 13.4 MΩ μm2, while the cathode charge-storage capacity (CSCc) reaches 24.2 ± 1.9 mC cm-2, which is 6.3 and 48.4 times higher than those of the commercial Ag electrodes, respectively. Density functional theory (DFT) results find that the Ag-graphene interface has more doped electronic states, providing faster electron transfer and enhanced interfacial transport. In vivo detection sensitivity and SNR of graphene/Ag electrodes are significantly improved. The current work provides a feasible solution for designing brain electrodes to monitor neural signals more sensitively and accurately.
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Affiliation(s)
- Shuangjie Liu
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Ling Liu
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Yue Zhao
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Yang Wang
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Yingpeng Wu
- State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Xiao-Dong Zhang
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics, School of Sciences, Tianjin University, Tianjin 300350, China
| | - Dong Ming
- Tianjin Key Laboratory of Brain Science and Neural Engineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
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24
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Chan D, Chien JC, Axpe E, Blankemeier L, Baker SW, Swaminathan S, Piunova VA, Zubarev DY, Maikawa CL, Grosskopf AK, Mann JL, Soh HT, Appel EA. Combinatorial Polyacrylamide Hydrogels for Preventing Biofouling on Implantable Biosensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022. [PMID: 35390209 DOI: 10.1101/2020.05.25.115675] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Biofouling on the surface of implanted medical devices and biosensors severely hinders device functionality and drastically shortens device lifetime. Poly(ethylene glycol) and zwitterionic polymers are currently considered "gold-standard" device coatings to reduce biofouling. To discover novel anti-biofouling materials, a combinatorial library of polyacrylamide-based copolymer hydrogels is created, and their ability is screened to prevent fouling from serum and platelet-rich plasma in a high-throughput parallel assay. It is found that certain nonintuitive copolymer compositions exhibit superior anti-biofouling properties over current gold-standard materials, and machine learning is used to identify key molecular features underpinning their performance. For validation, the surfaces of electrochemical biosensors are coated with hydrogels and their anti-biofouling performance in vitro and in vivo in rodent models is evaluated. The copolymer hydrogels preserve device function and enable continuous measurements of a small-molecule drug in vivo better than gold-standard coatings. The novel methodology described enables the discovery of anti-biofouling materials that can extend the lifetime of real-time in vivo sensing devices.
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Affiliation(s)
- Doreen Chan
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Jun-Chau Chien
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Eneko Axpe
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Louis Blankemeier
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Samuel W Baker
- Department of Comparative Medicine, Stanford University, Stanford, CA, 94305, USA
| | | | | | | | - Caitlin L Maikawa
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Abigail K Grosskopf
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Joseph L Mann
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - H Tom Soh
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
- ChEM-H Institute, Stanford University, Stanford, CA, 94304, USA
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
| | - Eric A Appel
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- ChEM-H Institute, Stanford University, Stanford, CA, 94304, USA
- Department of Pediatrics - Endocrinology, Stanford University School of Medicine, Stanford, CA, 94305, USA
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25
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Bhaskara S, Sakorikar T, Chatterjee S, Shabari Girishan K, Pandya HJ. Recent advancements in Micro-engineered devices for surface and deep brain animal studies: A review. SENSING AND BIO-SENSING RESEARCH 2022. [DOI: 10.1016/j.sbsr.2022.100483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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26
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Chan D, Chien JC, Axpe E, Blankemeier L, Baker SW, Swaminathan S, Piunova VA, Zubarev DY, Maikawa CL, Grosskopf AK, Mann JL, Soh HT, Appel EA. Combinatorial Polyacrylamide Hydrogels for Preventing Biofouling on Implantable Biosensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109764. [PMID: 35390209 PMCID: PMC9793805 DOI: 10.1002/adma.202109764] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/04/2022] [Indexed: 05/29/2023]
Abstract
Biofouling on the surface of implanted medical devices and biosensors severely hinders device functionality and drastically shortens device lifetime. Poly(ethylene glycol) and zwitterionic polymers are currently considered "gold-standard" device coatings to reduce biofouling. To discover novel anti-biofouling materials, a combinatorial library of polyacrylamide-based copolymer hydrogels is created, and their ability is screened to prevent fouling from serum and platelet-rich plasma in a high-throughput parallel assay. It is found that certain nonintuitive copolymer compositions exhibit superior anti-biofouling properties over current gold-standard materials, and machine learning is used to identify key molecular features underpinning their performance. For validation, the surfaces of electrochemical biosensors are coated with hydrogels and their anti-biofouling performance in vitro and in vivo in rodent models is evaluated. The copolymer hydrogels preserve device function and enable continuous measurements of a small-molecule drug in vivo better than gold-standard coatings. The novel methodology described enables the discovery of anti-biofouling materials that can extend the lifetime of real-time in vivo sensing devices.
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Affiliation(s)
- Doreen Chan
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Jun-Chau Chien
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Eneko Axpe
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Louis Blankemeier
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Samuel W Baker
- Department of Comparative Medicine, Stanford University, Stanford, CA, 94305, USA
| | | | | | | | - Caitlin L Maikawa
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Abigail K Grosskopf
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Joseph L Mann
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - H Tom Soh
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
- ChEM-H Institute, Stanford University, Stanford, CA, 94304, USA
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
| | - Eric A Appel
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- ChEM-H Institute, Stanford University, Stanford, CA, 94304, USA
- Department of Pediatrics - Endocrinology, Stanford University School of Medicine, Stanford, CA, 94305, USA
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27
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Kiang L, Woodington B, Carnicer-Lombarte A, Malliaras G, Barone DG. Spinal cord bioelectronic interfaces: opportunities in neural recording and clinical challenges. J Neural Eng 2022; 19. [PMID: 35320780 DOI: 10.1088/1741-2552/ac605f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/23/2022] [Indexed: 11/11/2022]
Abstract
Bioelectronic stimulation of the spinal cord has demonstrated significant progress in restoration of motor function in spinal cord injury (SCI). The proximal, uninjured spinal cord presents a viable target for the recording and generation of control signals to drive targeted stimulation. Signals have been directly recorded from the spinal cord in behaving animals and correlated with limb kinematics. Advances in flexible materials, electrode impedance and signal analysis will allow SCR to be used in next-generation neuroprosthetics. In this review, we summarize the technological advances enabling progress in SCR and describe systematically the clinical challenges facing spinal cord bioelectronic interfaces and potential solutions, from device manufacture, surgical implantation to chronic effects of foreign body reaction and stress-strain mismatches between electrodes and neural tissue. Finally, we establish our vision of bi-directional closed-loop spinal cord bioelectronic bypass interfaces that enable the communication of disrupted sensory signals and restoration of motor function in SCI.
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Affiliation(s)
- Lei Kiang
- Orthopaedic Surgery, Singapore General Hospital, Outram Road, Singapore, Singapore, 169608, SINGAPORE
| | - Ben Woodington
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Alejandro Carnicer-Lombarte
- Clinical Neurosciences, University of Cambridge, Bioelectronics Laboratory, Cambridge, CB2 0PY, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - George Malliaras
- University of Cambridge, University of Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Damiano G Barone
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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28
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Oldroyd P, Malliaras GG. Achieving long-term stability of thin-film electrodes for neurostimulation. Acta Biomater 2022; 139:65-81. [PMID: 34020055 DOI: 10.1016/j.actbio.2021.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/06/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022]
Abstract
Implantable electrodes that can reliably measure brain activity and deliver an electrical stimulus to a target tissue are increasingly employed to treat various neurological diseases and neuropsychiatric disorders. Flexible thin-film electrodes have gained attention over the past few years to minimise invasiveness and damage upon implantation. Research has previously focused on optimising the electrode's electrical and mechanical properties; however, their chronic stability must be validated to translate electrodes from a research to a clinical application. Neurostimulation electrodes, which actively inject charge, have yet to reliably demonstrate continuous functionality for ten years or more in vivo, the accepted metric for clinical viability. Long-term stability can only be achieved if the focus switches to investigating how and why such devices fail. Unfortunately, there is a field-wide reluctance to investigate device stability and failures, which hinders device optimisation. This review surveys thin-film electrode designs with a focus on adhesion between electrode layers and the interactions with the surrounding environment. A comprehensive summary of the abiotic failure modes faced by such electrodes is presented, and to encourage investigation, systematic methods for analysing their origin are recommended. Finally, approaches to reducing the likelihood of device failure are offered. STATEMENT OF SIGNIFICANCE: Neural electrodes that can deliver an electrical stimulus to a target tissue are widely used to treat various neurological diseases. Essential to the function of these electrodes is the ability to safely stimulate the target tissue for extended periods (> 10 years); however, this has not yet been clinically achieved. The key to achieving long-term stability is an increased understanding of electrode interactions with the surrounding tissue and subsequent systematic analysis of their failure modes. This review highlights the need for a change in the approach to investigating electrode failure, and in doing so summarizes the common ways in which neural electrodes fail, methods for identifying them and approaches to preventing them.
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29
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Degradation Study of Thin-Film Silicon Structures in a Cell Culture Medium. SENSORS 2022; 22:s22030802. [PMID: 35161547 PMCID: PMC8838160 DOI: 10.3390/s22030802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/16/2022]
Abstract
Thin-film silicon (Si)-based transient electronics represents an emerging technology that enables spontaneous dissolution, absorption and, finally, physical disappearance in a controlled manner under physiological conditions, and has attracted increasing attention in pertinent clinical applications such as biomedical implants for on-body sensing, disease diagnostics, and therapeutics. The degradation behavior of thin-film Si materials and devices is critically dependent on the device structure as well as the environment. In this work, we experimentally investigated the dissolution of planar Si thin films and micropatterned Si pillar arrays in a cell culture medium, and systematically analyzed the evolution of their topographical, physical, and chemical properties during the hydrolysis. We discovered that the cell culture medium significantly accelerates the degradation process, and Si pillar arrays present more prominent degradation effects by creating rougher surfaces, complicating surface states, and decreasing the electrochemical impedance. Additionally, the dissolution process leads to greatly reduced mechanical strength. Finally, in vitro cell culture studies demonstrate desirable biocompatibility of corroded Si pillars. The results provide a guideline for the use of thin-film Si materials and devices as transient implants in biomedicine.
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30
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Fu X, Li G, Niu Y, Xu J, Wang P, Zhou Z, Ye Z, Liu X, Xu Z, Yang Z, Zhang Y, Lei T, Zhang B, Li Q, Cao A, Jiang T, Duan X. Carbon-Based Fiber Materials as Implantable Depth Neural Electrodes. Front Neurosci 2022; 15:771980. [PMID: 35002602 PMCID: PMC8730365 DOI: 10.3389/fnins.2021.771980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/29/2021] [Indexed: 01/02/2023] Open
Abstract
Implantable brain electrophysiology electrodes are valuable tools in both fundamental and applied neuroscience due to their ability to record neural activity with high spatiotemporal resolution from shallow and deep brain regions. Their use has been hindered, however, by the challenges in achieving chronically stable operations. Furthermore, implantable depth neural electrodes can only carry out limited data sampling within predefined anatomical regions, making it challenging to perform large-area brain mapping. Minimizing inflammatory responses and associated gliosis formation, and improving the durability and stability of the electrode insulation layers are critical to achieve long-term stable neural recording and stimulation. Combining electrophysiological measurements with simultaneous whole-brain imaging techniques, such as magnetic resonance imaging (MRI), provides a useful solution to alleviate the challenge in scalability of implantable depth electrodes. In recent years, various carbon-based materials have been used to fabricate flexible neural depth electrodes with reduced inflammatory responses and MRI-compatible electrodes, which allows structural and functional MRI mapping of the whole brain without obstructing any brain regions around the electrodes. Here, we conducted a systematic comparative evaluation on the electrochemical properties, mechanical properties, and MRI compatibility of different kinds of carbon-based fiber materials, including carbon nanotube fibers, graphene fibers, and carbon fibers. We also developed a strategy to improve the stability of the electrode insulation without sacrificing the flexibility of the implantable depth electrodes by sandwiching an inorganic barrier layer inside the polymer insulation film. These studies provide us with important insights into choosing the most suitable materials for next-generation implantable depth electrodes with unique capabilities for applications in both fundamental and translational neuroscience research.
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Affiliation(s)
- Xuefeng Fu
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China
| | - Gen Li
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China
| | - Yutao Niu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou, China
| | - Jingcao Xu
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Puxin Wang
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Zhaoxiao Zhou
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Ziming Ye
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Xiaojun Liu
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China
| | - Zheng Xu
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China
| | - Ziqian Yang
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yongyi Zhang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou, China
| | - Ting Lei
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Baogui Zhang
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences (CAS), Beijing, China
| | - Qingwen Li
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou, China
| | - Anyuan Cao
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Tianzai Jiang
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences (CAS), Beijing, China
| | - Xiaojie Duan
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,National Biomedical Imaging Center, Peking University, Beijing, China
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31
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Sharafkhani N, Kouzani AZ, Adams SD, Long JM, Lissorgues G, Rousseau L, Orwa JO. Neural tissue-microelectrode interaction: Brain micromotion, electrical impedance, and flexible microelectrode insertion. J Neurosci Methods 2022; 365:109388. [PMID: 34678387 DOI: 10.1016/j.jneumeth.2021.109388] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/17/2021] [Accepted: 10/17/2021] [Indexed: 10/20/2022]
Abstract
Insertion of a microelectrode into the brain to record/stimulate neurons damages neural tissue and blood vessels and initiates the brain's wound healing response. Due to the large difference between the stiffness of neural tissue and microelectrode, brain micromotion also leads to neural tissue damage and associated local immune response. Over time, following implantation, the brain's response to the tissue damage can result in microelectrode failure. Reducing the microelectrode's cross-sectional dimensions to single-digit microns or using soft materials with elastic modulus close to that of the neural tissue are effective methods to alleviate the neural tissue damage and enhance microelectrode longevity. However, the increase in electrical impedance of the microelectrode caused by reducing the microelectrode contact site's dimensions can decrease the signal-to-noise ratio. Most importantly, the reduced dimensions also lead to a reduction in the critical buckling force, which increases the microelectrode's propensity to buckling during insertion. After discussing brain micromotion, the main source of neural tissue damage, surface modification of the microelectrode contact site is reviewed as a key method for addressing the increase in electrical impedance issue. The review then focuses on recent approaches to aiding insertion of flexible microelectrodes into the brain, including bending stiffness modification, effective length reduction, and application of a magnetic field to pull the electrode. An understanding of the advantages and drawbacks of the developed strategies offers a guide for dealing with the buckling phenomenon during implantation.
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Affiliation(s)
- Naser Sharafkhani
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia.
| | - Abbas Z Kouzani
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia
| | - Scott D Adams
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia
| | - John M Long
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia
| | | | | | - Julius O Orwa
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia.
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32
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Sponheim C, Papadourakis V, Collinger JL, Downey J, Weiss J, Pentousi L, Elliott K, Hatsopoulos N. Longevity and reliability of chronic unit recordings using the Utah, intracortical multi-electrode arrays. J Neural Eng 2021; 18:10.1088/1741-2552/ac3eaf. [PMID: 34847547 PMCID: PMC8981395 DOI: 10.1088/1741-2552/ac3eaf] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 11/30/2021] [Indexed: 12/30/2022]
Abstract
Objective.Microelectrode arrays are standard tools for conducting chronic electrophysiological experiments, allowing researchers to simultaneously record from large numbers of neurons. Specifically, Utah electrode arrays (UEAs) have been utilized by scientists in many species, including rodents, rhesus macaques, marmosets, and human participants. The field of clinical human brain-computer interfaces currently relies on the UEA as a number of research groups have clearance from the United States Federal Drug Administration (FDA) for this device through the investigational device exemption pathway. Despite its widespread usage in systems neuroscience, few studies have comprehensively evaluated the reliability and signal quality of the Utah array over long periods of time in a large dataset.Approach.We collected and analyzed over 6000 recorded datasets from various cortical areas spanning almost nine years of experiments, totaling 17 rhesus macaques (Macaca mulatta) and 2 human subjects, and 55 separate microelectrode Utah arrays. The scale of this dataset allowed us to evaluate the average life of these arrays, based primarily on the signal-to-noise ratio of each electrode over time.Main results.Using implants in primary motor, premotor, prefrontal, and somatosensory cortices, we found that the average lifespan of available recordings from UEAs was 622 days, although we provide several examples of these UEAs lasting over 1000 days and one up to 9 years; human implants were also shown to last longer than non-human primate implants. We also found that electrode length did not affect longevity and quality, but iridium oxide metallization on the electrode tip exhibited superior yield as compared to platinum metallization.Significance.Understanding longevity and reliability of microelectrode array recordings allows researchers to set expectations and plan experiments accordingly and maximize the amount of high-quality data gathered. Our results suggest that one can expect chronic unit recordings to last at least two years, with the possibility for arrays to last the better part of a decade.
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Affiliation(s)
- Caleb Sponheim
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL 60637
| | | | - Jennifer L. Collinger
- Rehab Neural Engineering Labs, Departments of Physical Medicine and Rehabilitation and Bioengineering, University of Pittsburgh, Pittsburgh, PA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA
| | - John Downey
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637
| | - Jeffrey Weiss
- Rehab Neural Engineering Labs, Departments of Physical Medicine and Rehabilitation and Bioengineering, University of Pittsburgh, Pittsburgh, PA
| | - Lida Pentousi
- Department of Neuroscience Physiology and Pharmacology, University College London, United Kingdom
| | - Kaisa Elliott
- University of Minnesota Medical School, Duluth Campus
| | - Nicholas Hatsopoulos
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL 60637
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Woeppel K, Hughes C, Herrera AJ, Eles JR, Tyler-Kabara EC, Gaunt RA, Collinger JL, Cui XT. Explant Analysis of Utah Electrode Arrays Implanted in Human Cortex for Brain-Computer-Interfaces. Front Bioeng Biotechnol 2021; 9:759711. [PMID: 34950640 PMCID: PMC8688945 DOI: 10.3389/fbioe.2021.759711] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/29/2021] [Indexed: 01/11/2023] Open
Abstract
Brain-computer interfaces are being developed to restore movement for people living with paralysis due to injury or disease. Although the therapeutic potential is great, long-term stability of the interface is critical for widespread clinical implementation. While many factors can affect recording and stimulation performance including electrode material stability and host tissue reaction, these factors have not been investigated in human implants. In this clinical study, we sought to characterize the material integrity and biological tissue encapsulation via explant analysis in an effort to identify factors that influence electrophysiological performance. We examined a total of six Utah arrays explanted from two human participants involved in intracortical BCI studies. Two platinum (Pt) arrays were implanted for 980 days in one participant (P1) and two Pt and two iridium oxide (IrOx) arrays were implanted for 182 days in the second participant (P2). We observed that the recording quality followed a similar trend in all six arrays with an initial increase in peak-to-peak voltage during the first 30–40 days and gradual decline thereafter in P1. Using optical and two-photon microscopy we observed a higher degree of tissue encapsulation on both arrays implanted for longer durations in participant P1. We then used scanning electron microscopy and energy dispersive X-ray spectroscopy to assess material degradation. All measures of material degradation for the Pt arrays were found to be more prominent in the participant with a longer implantation time. Two IrOx arrays were subjected to brief survey stimulations, and one of these arrays showed loss of iridium from most of the stimulated sites. Recording performance appeared to be unaffected by this loss of iridium, suggesting that the adhesion of IrOx coating may have been compromised by the stimulation, but the metal layer did not detach until or after array removal. In summary, both tissue encapsulation and material degradation were more pronounced in the arrays that were implanted for a longer duration. Additionally, these arrays also had lower signal amplitude and impedance. New biomaterial strategies that minimize fibrotic encapsulation and enhance material stability should be developed to achieve high quality recording and stimulation for longer implantation periods.
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Affiliation(s)
- Kevin Woeppel
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States
| | - Christopher Hughes
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs, Pittsburgh, PA, United States
| | - Angelica J Herrera
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs, Pittsburgh, PA, United States
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Elizabeth C Tyler-Kabara
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Department of Neurosurgery, The University of Texas at Austin, Austin, TX, United States
| | - Robert A Gaunt
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs, Pittsburgh, PA, United States.,Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jennifer L Collinger
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs, Pittsburgh, PA, United States.,Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States
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Usoro JO, Dogra K, Abbott JR, Radhakrishna R, Cogan SF, Pancrazio JJ, Patnaik SS. Influence of Implantation Depth on the Performance of Intracortical Probe Recording Sites. MICROMACHINES 2021; 12:1158. [PMID: 34683209 PMCID: PMC8539313 DOI: 10.3390/mi12101158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 09/18/2021] [Accepted: 09/24/2021] [Indexed: 02/06/2023]
Abstract
Microelectrode arrays (MEAs) enable the recording of electrical activity from cortical neurons which has implications for basic neuroscience and neuroprosthetic applications. The design space for MEA technology is extremely wide where devices may vary with respect to the number of monolithic shanks as well as placement of microelectrode sites. In the present study, we examine the differences in recording ability between two different MEA configurations: single shank (SS) and multi-shank (MS), both of which consist of 16 recording sites implanted in the rat motor cortex. We observed a significant difference in the proportion of active microelectrode sites over the 8-week indwelling period, in which SS devices exhibited a consistent ability to record activity, in contrast to the MS arrays which showed a marked decrease in activity within 2 weeks post-implantation. Furthermore, this difference was revealed to be dependent on the depth at which the microelectrode sites were located and may be mediated by anatomical heterogeneity, as well as the distribution of inhibitory neurons within the cortical layers. Our results indicate that the implantation depth of microelectrodes within the cortex needs to be considered relative to the chronic performance characterization.
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Affiliation(s)
| | | | | | | | | | - Joseph J. Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX 75080, USA; (J.O.U.); (K.D.); (J.R.A.); (R.R.); (S.F.C.); (S.S.P.)
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35
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Srikantharajah K, Medinaceli Quintela R, Doerenkamp K, Kampa BM, Musall S, Rothermel M, Offenhäusser A. Minimally-invasive insertion strategy and in vivo evaluation of multi-shank flexible intracortical probes. Sci Rep 2021; 11:18920. [PMID: 34556704 PMCID: PMC8460634 DOI: 10.1038/s41598-021-97940-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 08/26/2021] [Indexed: 11/16/2022] Open
Abstract
Chronically implanted neural probes are powerful tools to decode brain activity however, recording population and spiking activity over long periods remains a major challenge. Here, we designed and fabricated flexible intracortical Michigan-style arrays with a shank cross-section per electrode of 250 μm[Formula: see text] utilizing the polymer paryleneC with the goal to improve the immune acceptance. As flexible neural probes are unable to penetrate the brain due to the low buckling force threshold, a tissue-friendly insertion system was developed by reducing the effective shank length. The insertion strategy enabled the implantation of the four, bare, flexible shanks up to 2 mm into the mouse brain without increasing the implantation footprint and therefore, minimizing the acute trauma. In acute recordings from the mouse somatosensory cortex and the olfactory bulb, we demonstrated that the flexible probes were able to simultaneously detect local field potentials as well as single and multi-unit activity. Additionally, the flexible arrays outperformed stiff probes with respect to yield of single unit activity. Following the successful in vivo validation, we further improved the microfabrication towards a double-metal-layer process, and were able to double the number of electrodes per shank by keeping the shank width resulting in a cross-section per electrode of 118 μm[Formula: see text].
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Affiliation(s)
- Kagithiri Srikantharajah
- Bioelectronics, Institute of Biological Information Processing-3, Forschungszentrum Jülich, Jülich, Germany
- RWTH Aachen University, Aachen, Germany
| | - Renata Medinaceli Quintela
- Institute for Physiology and Cell Biology, University of Veterinary Medicine, Foundation, Hannover, Germany
| | - Kerstin Doerenkamp
- Department of Neurophysiology, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Björn M Kampa
- Department of Neurophysiology, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- JARA BRAIN, Institute for Neuroscience and Medicine, Forschungszentrum Jülich, Jülich, Germany
| | - Simon Musall
- Bioelectronics, Institute of Biological Information Processing-3, Forschungszentrum Jülich, Jülich, Germany
| | - Markus Rothermel
- Institute for Physiology and Cell Biology, University of Veterinary Medicine, Foundation, Hannover, Germany
| | - Andreas Offenhäusser
- Bioelectronics, Institute of Biological Information Processing-3, Forschungszentrum Jülich, Jülich, Germany.
- RWTH Aachen University, Aachen, Germany.
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36
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Zhao F, Sun J, Xue W, Wang F, King MW, Yu C, Jiao Y, Sun K, Wang L. Development of a polycaprolactone/poly( p-dioxanone) bioresorbable stent with mechanically self-reinforced structure for congenital heart disease treatment. Bioact Mater 2021; 6:2969-2982. [PMID: 33732967 PMCID: PMC7930591 DOI: 10.1016/j.bioactmat.2021.02.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/11/2021] [Accepted: 02/14/2021] [Indexed: 12/12/2022] Open
Abstract
Recent progress in bioresorbable stents (BRSs) has provided a promising alternative for treating coronary artery disease. However, there is still lack of BRSs with satisfied compression and degradation performance for pediatric patients with congenital heart disease, leading to suboptimal therapy effects. Here, we developed a mechanically self-reinforced composite bioresorbable stent (cBRS) for congenital heart disease application. The cBRS consisted of poly(p-dioxanone) monofilaments and polycaprolactone/poly(p-dioxanone) core-shell composite yarns. Interlacing points in cBRS structure were partially bonded, offering the cBRS with significantly higher compression force compared to typical braids and remained good compliance. The suitable degradation profile of the cBRS can possibly preserve vascular remodeling and healing process. In addition, the controllable structural organization provides a method to customize the performance of the cBRS by altering the proportion of different components in the braids. The in vivo results suggested the cBRS supported the vessel wall similar to that of metallic stent. In both abdominal aorta and iliac artery of porcine, cBRS was entirely endothelialized within 1 month and maintained target vessels with good patency in the 12-month follow-up. The in vivo degradation profile of the cBRS is consistent with static degradation results in vitro. It is also demonstrated that there is minimal impact of pulsatile pressure of blood flow and variation of radial force on the degradation rate of the cBRS. Moreover, the lumen of cBRS implanted vessels were enlarged after 6 months, and significantly larger than the vessels implanted with metallic stent in 12 months.
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Affiliation(s)
- Fan Zhao
- College of Textiles, Donghua University, Shanghai, 201620, China
- Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Songjiang District, Shanghai, 201620, China
- Wilson College of Textiles, North Carolina State University, Raleigh, 27606, USA
| | - Jing Sun
- Department of Pediatric Cardiology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, No. 1665 Kongjiang Road, Shanghai, 200092, China
| | - Wen Xue
- College of Textiles, Donghua University, Shanghai, 201620, China
- Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Songjiang District, Shanghai, 201620, China
| | - Fujun Wang
- College of Textiles, Donghua University, Shanghai, 201620, China
- Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Songjiang District, Shanghai, 201620, China
| | - Martin W. King
- Wilson College of Textiles, North Carolina State University, Raleigh, 27606, USA
| | - Chenglong Yu
- College of Textiles, Donghua University, Shanghai, 201620, China
- Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Songjiang District, Shanghai, 201620, China
| | - Yongjie Jiao
- College of Textiles, Donghua University, Shanghai, 201620, China
- Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Songjiang District, Shanghai, 201620, China
| | - Kun Sun
- Department of Pediatric Cardiology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, No. 1665 Kongjiang Road, Shanghai, 200092, China
| | - Lu Wang
- College of Textiles, Donghua University, Shanghai, 201620, China
- Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Songjiang District, Shanghai, 201620, China
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37
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Colachis SC, Dunlap CF, Annetta NV, Tamrakar SM, Bockbrader MA, Friedenberg DA. Long-term intracortical microelectrode array performance in a human: a 5 year retrospective analysis. J Neural Eng 2021; 18. [PMID: 34352736 DOI: 10.1088/1741-2552/ac1add] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 08/05/2021] [Indexed: 12/18/2022]
Abstract
Objective. Brain-computer interfaces (BCIs) that record neural activity using intracortical microelectrode arrays (MEAs) have shown promise for mitigating disability associated with neurological injuries and disorders. While the chronic performance and failure modes of MEAs have been well studied and systematically described in non-human primates, there is far less reported about long-term MEA performance in humans. Our group has collected one of the largest neural recording datasets from a Utah MEA in a human subject, spanning over 5 years (2014-2019). Here we present both long-term signal quality and BCI performance as well as highlight several acute signal disruption events observed during the clinical study.Approach. Long-term Utah array performance was evaluated by analyzing neural signal metric trends and decoding accuracy for tasks regularly performed across 448 clinical recording sessions. For acute signal disruptions, we identify or hypothesize the root cause of the disruption, show how the disruption manifests in the collected data, and discuss potential identification and mitigation strategies for the disruption.Main results. Neural signal quality metrics deteriorated rapidly within the first year, followed by a slower decline through the remainder of the study. Nevertheless, BCI performance remained high 5 years after implantation, which is encouraging for the translational potential of this technology as an assistive device. We also present examples of unanticipated signal disruptions during chronic MEA use, which are critical to detect as BCI technology progresses toward home usage.Significance. Our work fills a gap in knowledge around long-term MEA performance in humans, providing longevity and efficacy data points to help characterize the performance of implantable neural sensors in a human population. The trial was registered on ClinicalTrials.gov (Identifier NCT01997125) and conformed to institutional requirements for the conduct of human subjects research.
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Affiliation(s)
- Samuel C Colachis
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH 43201, United States of America.,Contributed equally
| | - Collin F Dunlap
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH 43201, United States of America.,Center for Neuromodulation, The Ohio State University, Columbus, OH 43210, United States of America.,Department of Physical Medicine and Rehabilitation, The Ohio State University, Columbus, OH 43210, United States of America.,Contributed equally
| | - Nicholas V Annetta
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH 43201, United States of America
| | - Sanjay M Tamrakar
- Health Analytics, Battelle Memorial Institute, Columbus, OH 43201, United States of America
| | - Marcia A Bockbrader
- Center for Neuromodulation, The Ohio State University, Columbus, OH 43210, United States of America.,Department of Physical Medicine and Rehabilitation, The Ohio State University, Columbus, OH 43210, United States of America
| | - David A Friedenberg
- Health Analytics, Battelle Memorial Institute, Columbus, OH 43201, United States of America
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38
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Intracortical Microelectrode Array Unit Yield under Chronic Conditions: A Comparative Evaluation. MICROMACHINES 2021; 12:mi12080972. [PMID: 34442594 PMCID: PMC8400387 DOI: 10.3390/mi12080972] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 01/01/2023]
Abstract
While microelectrode arrays (MEAs) offer the promise of elucidating functional neural circuitry and serve as the basis for a cortical neuroprosthesis, the challenge of designing and demonstrating chronically reliable technology remains. Numerous studies report “chronic” data but the actual time spans and performance measures corresponding to the experimental work vary. In this study, we reviewed the experimental durations that constitute chronic studies across a range of MEA types and animal species to gain an understanding of the widespread variability in reported study duration. For rodents, which are the most commonly used animal model in chronic studies, we examined active electrode yield (AEY) for different array types as a means to contextualize the study duration variance, as well as investigate and interpret the performance of custom devices in comparison to conventional MEAs. We observed wide-spread variance within species for the chronic implantation period and an AEY that decayed linearly in rodent models that implanted commercially-available devices. These observations provide a benchmark for comparing the performance of new technologies and highlight the need for consistency in chronic MEA studies. Additionally, to fully derive performance under chronic conditions, the duration of abiotic failure modes, biological processes induced by indwelling probes, and intended application of the device are key determinants.
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39
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Francoeur MJ, Tang T, Fakhraei L, Wu X, Hulyalkar S, Cramer J, Buscher N, Ramanathan DR. Chronic, Multi-Site Recordings Supported by Two Low-Cost, Stationary Probe Designs Optimized to Capture Either Single Unit or Local Field Potential Activity in Behaving Rats. Front Psychiatry 2021; 12:678103. [PMID: 34421671 PMCID: PMC8374626 DOI: 10.3389/fpsyt.2021.678103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/21/2021] [Indexed: 11/13/2022] Open
Abstract
Rodent models of cognitive behavior have greatly contributed to our understanding of human neuropsychiatric disorders. However, to elucidate the neurobiological underpinnings of such disorders or impairments, animal models are more useful when paired with methods for measuring brain function in awake, behaving animals. Standard tools used for systems-neuroscience level investigations are not optimized for large-scale and high-throughput behavioral battery testing due to various factors including cost, time, poor longevity, and selective targeting limited to measuring only a few brain regions at a time. Here we describe two different "user-friendly" methods for building extracellular electrophysiological probes that can be used to measure either single units or local field potentials in rats performing cognitive tasks. Both probe designs leverage several readily available, yet affordable, commercial products to facilitate ease of production and offer maximum flexibility in terms of brain-target locations that can be scalable (32-64 channels) based on experimental needs. Our approach allows neural activity to be recorded simultaneously with behavior and compared between micro (single unit) and more macro (local field potentials) levels of brain activity in order to gain a better understanding of how local brain regions and their connected networks support cognitive functions in rats. We believe our novel probe designs make collecting electrophysiology data easier and will begin to fill the gap in knowledge between basic and clinical research.
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Affiliation(s)
- Miranda J. Francoeur
- Mental Health Service, VA San Diego Healthcare System, San Diego, CA, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
| | - Tianzhi Tang
- Mental Health Service, VA San Diego Healthcare System, San Diego, CA, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
| | - Leila Fakhraei
- Mental Health Service, VA San Diego Healthcare System, San Diego, CA, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
| | - Xuanyu Wu
- Mental Health Service, VA San Diego Healthcare System, San Diego, CA, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
| | - Sidharth Hulyalkar
- Mental Health Service, VA San Diego Healthcare System, San Diego, CA, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
| | - Jessica Cramer
- Mental Health Service, VA San Diego Healthcare System, San Diego, CA, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
| | - Nathalie Buscher
- Mental Health Service, VA San Diego Healthcare System, San Diego, CA, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
| | - Dhakshin R. Ramanathan
- Mental Health Service, VA San Diego Healthcare System, San Diego, CA, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
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40
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Mani N, Ahnood A, Peng D, Tong W, Booth M, Jones A, Murdoch B, Tran N, Houshyar S, Fox K. Single-Step Fabrication Method toward 3D Printing Composite Diamond-Titanium Interfaces for Neural Applications. ACS APPLIED MATERIALS & INTERFACES 2021; 13:31474-31484. [PMID: 34192459 DOI: 10.1021/acsami.1c07318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Owing to several key attributes, diamond is an attractive candidate material for neural interfacing electrodes. The emergence of additive-manufacturing (AM) of diamond-based materials has addressed multiple challenges associated with the fabrication of diamond electrodes using the conventional chemical vapor deposition (CVD) approach. Unlike the CVD approach, AM methods have enabled the deposition of three-dimensional diamond-based material at room temperature. This work demonstrates the feasibility of using laser metal deposition to fabricate diamond-titanium hybrid electrodes for neuronal interfacing. In addition to exhibiting a high electrochemical capacitance of 1.1 mF cm-2 and a low electrochemical impedance of 1 kΩ cm2 at 1 kHz in physiological saline, these electrodes exhibit a high degree of biocompatibility assessed in vitro using cortical neurons. Furthermore, surface characterization methods show the presence of an oxygen-rich mixed-phase diamond-titanium surface along the grain boundaries. Overall, we demonstrated that our unique approach facilitates printing biocompatible titanium-diamond site-specific coating-free conductive hybrid surfaces using AM, which paves the way to printing customized electrodes and interfacing implantable medical devices.
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Affiliation(s)
- Nour Mani
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3001, Australia
- Centre for Additive Manufacturing, RMIT University, 58 Cardigan Street, Melbourne, Victoria 3001, Australia
| | - Arman Ahnood
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3001, Australia
| | - Danli Peng
- School of Physics, The University of Melbourne, Tin Alley, Parkville, Melbourne, Victoria 3010, Australia
| | - Wei Tong
- School of Physics, The University of Melbourne, Tin Alley, Parkville, Melbourne, Victoria 3010, Australia
- National Vision Research Institute, Australian College of Optometry, Carlton, Victoria 3010, Australia
| | - Marsilea Booth
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3001, Australia
| | - Alan Jones
- Centre for Additive Manufacturing, RMIT University, 58 Cardigan Street, Melbourne, Victoria 3001, Australia
| | - Billy Murdoch
- RMIT Microscopy and Microanalysis Facility, 124 La Trobe Street, Melbourne, Victoria 3001, Australia
| | - Nhiem Tran
- School of Science, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3001, Australia
| | - Shadi Houshyar
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3001, Australia
| | - Kate Fox
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3001, Australia
- Centre for Additive Manufacturing, RMIT University, 58 Cardigan Street, Melbourne, Victoria 3001, Australia
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41
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Feng C, Frewin CL, Tanjil MRE, Everly R, Bieber J, Kumar A, Wang MC, Saddow SE. A Flexible a-SiC-Based Neural Interface Utilizing Pyrolyzed-Photoresist Film (C) Active Sites. MICROMACHINES 2021; 12:821. [PMID: 34357231 PMCID: PMC8304835 DOI: 10.3390/mi12070821] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/07/2021] [Accepted: 07/10/2021] [Indexed: 01/06/2023]
Abstract
Carbon containing materials, such as graphene, carbon-nanotubes (CNT), and graphene oxide, have gained prominence as possible electrodes in implantable neural interfaces due to their excellent conductive properties. While carbon is a promising electrochemical interface, many fabrication processes are difficult to perform, leading to issues with large scale device production and overall repeatability. Here we demonstrate that carbon electrodes and traces constructed from pyrolyzed-photoresist-film (PPF) when combined with amorphous silicon carbide (a-SiC) insulation could be fabricated with repeatable processes which use tools easily available in most semiconductor facilities. Directly forming PPF on a-SiC simplified the fabrication process which eliminates noble metal evaporation/sputtering and lift-off processes on small features. PPF electrodes in oxygenated phosphate buffered solution at pH 7.4 demonstrated excellent electrochemical charge storage capacity (CSC) of 14.16 C/cm2, an impedance of 24.8 ± 0.4 kΩ, and phase angle of -35.9 ± 0.6° at 1 kHz with a 1.9 kµm2 recording site area.
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Affiliation(s)
- Chenyin Feng
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA;
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | | | - Md Rubayat-E Tanjil
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | - Richard Everly
- Nanotechnology Research & Education Center, University of South Florida, Tampa, FL 33620, USA; (R.E.); (J.B.)
| | - Jay Bieber
- Nanotechnology Research & Education Center, University of South Florida, Tampa, FL 33620, USA; (R.E.); (J.B.)
| | - Ashok Kumar
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | - Michael Cai Wang
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | - Stephen E. Saddow
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA;
- Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA
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42
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Liu X, Bibineyshvili Y, Robles DA, Boreland AJ, Margolis DJ, Shreiber DI, Zahn JD. Fabrication of a Multilayer Implantable Cortical Microelectrode Probe to Improve Recording Potential. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2021; 30:569-581. [PMID: 34539168 PMCID: PMC8445332 DOI: 10.1109/jmems.2021.3092230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Intracortical neural probes are a key enabling technology for acquiring high fidelity neural signals within the cortex. They are viewed as a crucial component of brain-computer interfaces (BCIs) in order to record electrical activities from neurons within the brain. Smaller, more flexible, polymer-based probes have been investigated for their potential to limit the acute and chronic neural tissue response. Conventional methods of patterning electrodes and connecting traces on a single supporting layer can limit the number of recording sites which can be defined, particularly when designing narrower probes. We present a novel strategy of increasing the number of recording sites without proportionally increasing the size of the probe by using a multilayer fabrication process to vertically layer recording traces on multiple Parylene support layers, allowing more recording traces to be defined on a smaller probe width. Using this approach, we are able to define 16 electrodes on 4 supporting layers (4 electrodes per layer), each with a 30 μm diameter recording window and 5 μm wide connecting trace defined by conventional LWUV lithography, on an 80 μm wide by 9 μm thick microprobe. Prior to in vitro and in vivo validation, the multilayer probes are electrically characterized via impedance spectroscopy and evaluating crosstalk between adjacent layers. Demonstration of acute in vitro recordings in a cerebral organoid model and in vivo recordings in a murine model indicate the probe's capability for single unit recordings. This work demonstrates the ability to fabricate smaller, more compliant neural probes without sacrificing electrode density.
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Affiliation(s)
- Xin Liu
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| | - Yelena Bibineyshvili
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA
| | - Denise A Robles
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| | - Andrew J Boreland
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA
| | - David J Margolis
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA
| | - David I Shreiber
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| | - Jeffrey D Zahn
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
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43
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Sridharan A, Muthuswamy J. Soft, Conductive, Brain-Like, Coatings at Tips of Microelectrodes Improve Electrical Stability under Chronic, In Vivo Conditions. MICROMACHINES 2021; 12:761. [PMID: 34203234 PMCID: PMC8306035 DOI: 10.3390/mi12070761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/22/2021] [Accepted: 06/25/2021] [Indexed: 01/27/2023]
Abstract
Several recent studies have reported improved histological and electrophysiological outcomes with soft neural interfaces that have elastic moduli ranging from 10 s of kPa to hundreds of MPa. However, many of these soft interfaces use custom fabrication processes. We test the hypothesis that a readily adoptable fabrication process for only coating the tips of microelectrodes with soft brain-like (elastic modulus of ~5 kPa) material improves the long-term electrical performance of neural interfaces. Conventional tungsten microelectrodes (n = 9 with soft coatings and n = 6 uncoated controls) and Pt/Ir microelectrodes (n = 16 with soft coatings) were implanted in six animals for durations ranging from 5 weeks to over 1 year in a subset of rats. Electrochemical impedance spectroscopy was used to assess the quality of the brain tissue-electrode interface under chronic conditions. Neural recordings were assessed for unit activity and signal quality. Electrodes with soft, silicone coatings showed relatively stable electrical impedance characteristics over 6 weeks to >1 year compared to the uncoated control electrodes. Single unit activity recorded by coated electrodes showed larger peak-to-peak amplitudes and increased number of detectable neurons compared to uncoated controls over 6-7 weeks. We demonstrate the feasibility of using a readily translatable process to create brain-like soft interfaces that can potentially overcome variable performance associated with chronic rigid neural interfaces.
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Affiliation(s)
| | - Jit Muthuswamy
- School of Biological and Health Systems Engineering, Ira A. Fulton School of Engineering, Arizona State University, Tempe, AZ 85287-9709, USA;
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44
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Zheng XS, Tan C, Castagnola E, Cui XT. Electrode Materials for Chronic Electrical Microstimulation. Adv Healthc Mater 2021; 10:e2100119. [PMID: 34029008 PMCID: PMC8257249 DOI: 10.1002/adhm.202100119] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/20/2021] [Indexed: 02/06/2023]
Abstract
Electrical microstimulation has enabled partial restoration of vision, hearing, movement, somatosensation, as well as improving organ functions by electrically modulating neural activities. However, chronic microstimulation is faced with numerous challenges. The implantation of an electrode array into the neural tissue triggers an inflammatory response, which can be exacerbated by the delivery of electrical currents. Meanwhile, prolonged stimulation may lead to electrode material degradation., which can be accelerated by the hostile inflammatory environment. Both material degradation and adverse tissue reactions can compromise stimulation performance over time. For stable chronic electrical stimulation, an ideal microelectrode must present 1) high charge injection limit, to efficiently deliver charge without exceeding safety limits for both tissue and electrodes, 2) small size, to gain high spatial selectivity, 3) excellent biocompatibility that ensures tissue health immediately next to the device, and 4) stable in vivo electrochemical properties over the application period. In this review, the challenges in chronic microstimulation are described in detail. To aid material scientists interested in neural stimulation research, the in vitro and in vivo testing methods are introduced for assessing stimulation functionality and longevity and a detailed overview of recent advances in electrode material research and device fabrication for improving chronic microstimulation performance is provided.
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Affiliation(s)
- Xin Sally Zheng
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Chao Tan
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
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45
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Kolaya E, Firestein BL. Deep brain stimulation: Challenges at the tissue-electrode interface and current solutions. Biotechnol Prog 2021; 37:e3179. [PMID: 34056871 DOI: 10.1002/btpr.3179] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/19/2021] [Accepted: 05/27/2021] [Indexed: 11/08/2022]
Abstract
Deep brain stimulation (DBS) is used to treat the motor symptoms of Parkinson's disease patients by stimulating the subthalamic nucleus. However, optimization of DBS is still needed since the performance of the neural electrodes is limited by the body's response to the implant. This review discusses the issues with DBS, such as placement of electrodes, foreign body response, and electrode degradation. The current solutions to these technical issues include modifications to electrode material, coatings, and geometry.
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Affiliation(s)
- Emily Kolaya
- Biomedical Engineering Graduate Program, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
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46
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McGlynn E, Nabaei V, Ren E, Galeote‐Checa G, Das R, Curia G, Heidari H. The Future of Neuroscience: Flexible and Wireless Implantable Neural Electronics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002693. [PMID: 34026431 PMCID: PMC8132070 DOI: 10.1002/advs.202002693] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/15/2021] [Indexed: 05/04/2023]
Abstract
Neurological diseases are a prevalent cause of global mortality and are of growing concern when considering an ageing global population. Traditional treatments are accompanied by serious side effects including repeated treatment sessions, invasive surgeries, or infections. For example, in the case of deep brain stimulation, large, stiff, and battery powered neural probes recruit thousands of neurons with each pulse, and can invoke a vigorous immune response. This paper presents challenges in engineering and neuroscience in developing miniaturized and biointegrated alternatives, in the form of microelectrode probes. Progress in design and topology of neural implants has shifted the goal post toward highly specific recording and stimulation, targeting small groups of neurons and reducing the foreign body response with biomimetic design principles. Implantable device design recommendations, fabrication techniques, and clinical evaluation of the impact flexible, integrated probes will have on the treatment of neurological disorders are provided in this report. The choice of biocompatible material dictates fabrication techniques as novel methods reduce the complexity of manufacture. Wireless power, the final hurdle to truly implantable neural interfaces, is discussed. These aspects are the driving force behind continued research: significant breakthroughs in any one of these areas will revolutionize the treatment of neurological disorders.
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Affiliation(s)
- Eve McGlynn
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Vahid Nabaei
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Elisa Ren
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Gabriel Galeote‐Checa
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Rupam Das
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Giulia Curia
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Hadi Heidari
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
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47
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McNamara M, Ersöz A, Han M. A Diagnostic Circuit for Crosstalk Detection in Microelectrode Arrays. INTERNATIONAL IEEE/EMBS CONFERENCE ON NEURAL ENGINEERING : [PROCEEDINGS]. INTERNATIONAL IEEE EMBS CONFERENCE ON NEURAL ENGINEERING 2021; 2021:544-547. [PMID: 34925703 PMCID: PMC8674810 DOI: 10.1109/ner49283.2021.9441164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Current leakage between channels in microelectrode arrays is a sign of device failure and can lead to shorting of neural signals. The purpose of this project is to detect crosstalk between 32 channels of electrodes. We designed an embedded crosstalk detection system that can stimulate each electrode individually with a constant-current pulse and record voltage transients of the stimulated and adjacent electrodes to generate a matrix of crosstalk values. Charge injection in a phosphate buffered saline solution was used to check the condition of each electrode. A semi-wet condition was then used to determine the percent crosstalk between the channels. The analysis showed that there was minimal crosstalk between the electrodes, except for a known physical defect on the probe. The measurement technique enabled by the electronics circuit has the potential to be used in functional testing and screening of implantable devices.
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Affiliation(s)
- Morgan McNamara
- Biomedical Engineering Department, University of Connecticut, Storrs, CT 06269 USA
| | - Alpaslan Ersöz
- Biomedical Engineering Department, University of Connecticut, Storrs, CT 06269 USA
| | - Martin Han
- Biomedical Engineering Department, University of Connecticut, Storrs, CT 06269 USA
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48
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Hejazi M, Tong W, Ibbotson MR, Prawer S, Garrett DJ. Advances in Carbon-Based Microfiber Electrodes for Neural Interfacing. Front Neurosci 2021; 15:658703. [PMID: 33912007 PMCID: PMC8072048 DOI: 10.3389/fnins.2021.658703] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
Neural interfacing devices using penetrating microelectrode arrays have emerged as an important tool in both neuroscience research and medical applications. These implantable microelectrode arrays enable communication between man-made devices and the nervous system by detecting and/or evoking neuronal activities. Recent years have seen rapid development of electrodes fabricated using flexible, ultrathin carbon-based microfibers. Compared to electrodes fabricated using rigid materials and larger cross-sections, these microfiber electrodes have been shown to reduce foreign body responses after implantation, with improved signal-to-noise ratio for neural recording and enhanced resolution for neural stimulation. Here, we review recent progress of carbon-based microfiber electrodes in terms of material composition and fabrication technology. The remaining challenges and future directions for development of these arrays will also be discussed. Overall, these microfiber electrodes are expected to improve the longevity and reliability of neural interfacing devices.
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Affiliation(s)
- Maryam Hejazi
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - Wei Tong
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
| | - Michael R. Ibbotson
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Steven Prawer
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - David J. Garrett
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- School of Engineering, RMIT University, Melbourne, VIC, Australia
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49
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Sharon A, Jankowski MM, Shmoel N, Erez H, Spira ME. Inflammatory Foreign Body Response Induced by Neuro-Implants in Rat Cortices Depleted of Resident Microglia by a CSF1R Inhibitor and Its Implications. Front Neurosci 2021; 15:646914. [PMID: 33841088 PMCID: PMC8032961 DOI: 10.3389/fnins.2021.646914] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/25/2021] [Indexed: 12/30/2022] Open
Abstract
Inflammatory encapsulation of implanted cortical-neuro-probes [the foreign body response (FBR)] severely limits their use in basic brain research and in clinical applications. A better understanding of the inflammatory FBR is needed to effectively mitigate these critical limitations. Combining the use of the brain permeant colony stimulating factor 1 receptor inhibitor PLX5622 and a perforated polyimide-based multielectrode array platform (PPMP) that can be sectioned along with the surrounding tissue, we examined the contribution of microglia to the formation of inflammatory FBR. To that end, we imaged the inflammatory processes induced by PPMP implantations after eliminating 89-94% of the cortical microglia by PLX5622 treatment. The observations showed that: (I) inflammatory encapsulation of implanted PPMPs proceeds by astrocytes in microglia-free cortices. The activated astrocytes adhered to the PPMP's surfaces. This suggests that the roles of microglia in the FBR might be redundant. (II) PPMP implantation into control or continuously PLX5622-treated rats triggered a localized surge of microglia mitosis. The daughter cells that formed a "cloud" of short-lived (T 1 / 2 ≤ 14 days) microglia around and in contact with the implant surfaces were PLX5622 insensitive. (III) Neuron degeneration by PPMP implantation and the ensuing recovery in time, space, and density progressed in a similar manner in the cortices following 89-94% depletion of microglia. This implies that microglia do not serve a protective role with respect to the neurons. (IV) Although the overall cell composition and dimensions of the encapsulating scar in PLX5622-treated rats differed from the controls, the recorded field potential (FP) qualities and yield were undistinguishable. This is accounted for by assuming that the FP amplitudes in the control and PLX5622-treated rats were related to the seal resistance formed at the interface between the adhering microglia and/or astrocytes and the PPMP platform rather than across the scar tissue. These observations suggest that the prevention of both astrocytes and microglia adhesion to the electrodes is required to improve FP recording quality and yield.
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Affiliation(s)
- Aviv Sharon
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maciej M. Jankowski
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nava Shmoel
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hadas Erez
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Micha E. Spira
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
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50
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Dubaniewicz M, Eles JR, Lam S, Song S, Cambi F, Sun D, Wellman SM, Kozai TDY. Inhibition of Na +/H +exchanger modulates microglial activation and scar formation following microelectrode implantation. J Neural Eng 2021; 18. [PMID: 33621208 DOI: 10.1088/1741-2552/abe8f1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/23/2021] [Indexed: 11/12/2022]
Abstract
Objective.Intracortical microelectrodes are an important tool for neuroscience research and have great potential for clinical use. However, the use of microelectrode arrays to treat neurological disorders and control prosthetics is limited by biological challenges such as glial scarring, which can impair chronic recording performance. Microglia activation is an early and prominent contributor to glial scarring. After insertion of an intracortical microelectrode, nearby microglia transition into a state of activation, migrate, and encapsulate the device. Na+/H+exchanger isoform-1 (NHE-1) is involved in various microglial functions, including their polarity and motility, and has been implicated in pro-inflammatory responses to tissue injury. HOE-642 (cariporide) is an inhibitor of NHE-1 and has been shown to depress microglial activation and inflammatory response in brain injury models.Approach.In this study, the effects of HOE-642 treatment on microglial interactions to intracortical microelectrodes was evaluated using two-photon microscopyin vivo.Main results.The rate at which microglia processes and soma migrate in response to electrode implantation was unaffected by HOE-642 administration. However, HOE-642 administration effectively reduced the radius of microglia activation at 72 h post-implantation from 222.2µm to 177.9µm. Furthermore, treatment with HOE-642 significantly reduced microglial encapsulation of implanted devices at 5 h post-insertion from 50.7 ± 6.0% to 8.9 ± 6.1%, which suggests an NHE-1-specific mechanism mediating microglia reactivity and gliosis during implantation injury.Significance.This study implicates NHE-1 as a potential target of interest in microglial reactivity and HOE-642 as a potential treatment to attenuate the glial response and scar formation around implanted intracortical microelectrodes.
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Affiliation(s)
- Mitchell Dubaniewicz
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Stephanie Lam
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Franca Cambi
- Veterans Administration Pittsburgh, Pittsburgh, PA, United States of America.,Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Dandan Sun
- Veterans Administration Pittsburgh, Pittsburgh, PA, United States of America.,Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America.,Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America.,NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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