1
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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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2
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Sharafkhani N, Long JM, Adams SD, Kouzani AZ. A self-stiffening compliant intracortical microprobe. Biomed Microdevices 2024; 26:17. [PMID: 38345721 PMCID: PMC10861748 DOI: 10.1007/s10544-024-00700-7] [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] [Accepted: 02/06/2024] [Indexed: 02/15/2024]
Abstract
Utilising a flexible intracortical microprobe to record/stimulate neurons minimises the incompatibility between the implanted microprobe and the brain, reducing tissue damage due to the brain micromotion. Applying bio-dissolvable coating materials temporarily makes a flexible microprobe stiff to tolerate the penetration force during insertion. However, the inability to adjust the dissolving time after the microprobe contact with the cerebrospinal fluid may lead to inaccuracy in the microprobe positioning. Furthermore, since the dissolving process is irreversible, any subsequent positioning error cannot be corrected by re-stiffening the microprobe. The purpose of this study is to propose an intracortical microprobe that incorporates two compressible structures to make the microprobe both adaptive to the brain during operation and stiff during insertion. Applying a compressive force by an inserter compresses the two compressible structures completely, resulting in increasing the equivalent elastic modulus. Thus, instant switching between stiff and soft modes can be accomplished as many times as necessary to ensure high-accuracy positioning while causing minimal tissue damage. The equivalent elastic modulus of the microprobe during operation is ≈ 23 kPa, which is ≈ 42% less than the existing counterpart, resulting in ≈ 46% less maximum strain generated on the surrounding tissue under brain longitudinal motion. The self-stiffening microprobe and surrounding neural tissue are simulated during insertion and operation to confirm the efficiency of the design. Two-photon polymerisation technology is utilised to 3D print the proposed microprobe, which is experimentally validated and inserted into a lamb's brain without buckling.
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Affiliation(s)
- Naser Sharafkhani
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - John M Long
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - Scott D Adams
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - Abbas Z Kouzani
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia.
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3
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Walter C, Balouchzadeh R, Garcia KE, Kroenke CD, Pathak A, Bayly PV. Multi-scale measurement of stiffness in the developing ferret brain. Sci Rep 2023; 13:20583. [PMID: 37996465 PMCID: PMC10667369 DOI: 10.1038/s41598-023-47900-4] [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: 09/12/2023] [Accepted: 11/20/2023] [Indexed: 11/25/2023] Open
Abstract
Cortical folding is an important process during brain development, and aberrant folding is linked to disorders such as autism and schizophrenia. Changes in cell numbers, size, and morphology have been proposed to exert forces that control the folding process, but these changes may also influence the mechanical properties of developing brain tissue. Currently, the changes in tissue stiffness during brain folding are unknown. Here, we report stiffness in the developing ferret brain across multiple length scales, emphasizing changes in folding cortical tissue. Using rheometry to measure the bulk properties of brain tissue, we found that overall brain stiffness increases with age over the period of cortical folding. Using atomic force microscopy to target the cortical plate, we found that the occipital cortex increases in stiffness as well as stiffness heterogeneity over the course of development and folding. These findings can help to elucidate the mechanics of the cortical folding process by clarifying the concurrent evolution of tissue properties.
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Affiliation(s)
- Christopher Walter
- Mechanical Engineering and Materials Science, Washington University, St. Louis, USA.
| | - Ramin Balouchzadeh
- Mechanical Engineering and Materials Science, Washington University, St. Louis, USA
| | - Kara E Garcia
- Radiology and Imaging Sciences, Indiana University School of Medicine, Evansville, IN, USA
| | - Christopher D Kroenke
- Advanced Imaging Research Center and Oregon National Primate Research Center Division of Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Amit Pathak
- Mechanical Engineering and Materials Science, Washington University, St. Louis, USA
| | - Philip V Bayly
- Mechanical Engineering and Materials Science, Washington University, St. Louis, USA.
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4
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Perna A, Angotzi GN, Berdondini L, Ribeiro JF. Advancing the interfacing performances of chronically implantable neural probes in the era of CMOS neuroelectronics. Front Neurosci 2023; 17:1275908. [PMID: 38027514 PMCID: PMC10644322 DOI: 10.3389/fnins.2023.1275908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 10/10/2023] [Indexed: 12/01/2023] Open
Abstract
Tissue penetrating microelectrode neural probes can record electrophysiological brain signals at resolutions down to single neurons, making them invaluable tools for neuroscience research and Brain-Computer-Interfaces (BCIs). The known gradual decrease of their electrical interfacing performances in chronic settings, however, remains a major challenge. A key factor leading to such decay is Foreign Body Reaction (FBR), which is the cascade of biological responses that occurs in the brain in the presence of a tissue damaging artificial device. Interestingly, the recent adoption of Complementary Metal Oxide Semiconductor (CMOS) technology to realize implantable neural probes capable of monitoring hundreds to thousands of neurons simultaneously, may open new opportunities to face the FBR challenge. Indeed, this shift from passive Micro Electro-Mechanical Systems (MEMS) to active CMOS neural probe technologies creates important, yet unexplored, opportunities to tune probe features such as the mechanical properties of the probe, its layout, size, and surface physicochemical properties, to minimize tissue damage and consequently FBR. Here, we will first review relevant literature on FBR to provide a better understanding of the processes and sources underlying this tissue response. Methods to assess FBR will be described, including conventional approaches based on the imaging of biomarkers, and more recent transcriptomics technologies. Then, we will consider emerging opportunities offered by the features of CMOS probes. Finally, we will describe a prototypical neural probe that may meet the needs for advancing clinical BCIs, and we propose axial insertion force as a potential metric to assess the influence of probe features on acute tissue damage and to control the implantation procedure to minimize iatrogenic injury and subsequent FBR.
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Affiliation(s)
- Alberto Perna
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
- The Open University Affiliated Research Centre at Istituto Italiano di Tecnologia (ARC@IIT), Istituto Italiano di Tecnologia, Genova, Italy
| | - Gian Nicola Angotzi
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
| | - Luca Berdondini
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
| | - João Filipe Ribeiro
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
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5
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Tracking neural activity from the same cells during the entire adult life of mice. Nat Neurosci 2023; 26:696-710. [PMID: 36804648 DOI: 10.1038/s41593-023-01267-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/19/2023] [Indexed: 02/22/2023]
Abstract
Stably recording the electrical activity of the same neurons over the adult life of an animal is important to neuroscience research and biomedical applications. Current implantable devices cannot provide stable recording on this timescale. Here, we introduce a method to precisely implant electronics with an open, unfolded mesh structure across multiple brain regions in the mouse. The open mesh structure forms a stable interwoven structure with the neural network, preventing probe drifting and showing no immune response and neuron loss during the year-long implantation. Rigorous statistical analysis, visual stimulus-dependent measurement and unbiased, machine-learning-based analysis demonstrated that single-unit action potentials have been recorded from the same neurons of behaving mice in a very long-term stable manner. Leveraging this stable structure, we demonstrated that the same neurons can be recorded over the entire adult life of the mouse, revealing the aging-associated evolution of single-neuron activities.
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6
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Kumosa LS. Commonly Overlooked Factors in Biocompatibility Studies of Neural Implants. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205095. [PMID: 36596702 PMCID: PMC9951391 DOI: 10.1002/advs.202205095] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 11/16/2022] [Indexed: 06/17/2023]
Abstract
Biocompatibility of cutting-edge neural implants, surgical tools and techniques, and therapeutic technologies is a challenging concept that can be easily misjudged. For example, neural interfaces are routinely gauged on how effectively they determine active neurons near their recording sites. Tissue integration and toxicity of neural interfaces are frequently assessed histologically in animal models to determine tissue morphological and cellular changes in response to surgical implantation and chronic presence. A disconnect between histological and efficacious biocompatibility exists, however, as neuronal numbers frequently observed near electrodes do not match recorded neuronal spiking activity. The downstream effects of the myriad surgical and experimental factors involved in such studies are rarely examined when deciding whether a technology or surgical process is biocompatible. Such surgical factors as anesthesia, temperature excursions, bleed incidence, mechanical forces generated, and metabolic conditions are known to have strong systemic and thus local cellular and extracellular consequences. Many tissue markers are extremely sensitive to the physiological state of cells and tissues, thus significantly impacting histological accuracy. This review aims to shed light on commonly overlooked factors that can have a strong impact on the assessment of neural biocompatibility and to address the mismatch between results stemming from functional and histological methods.
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Affiliation(s)
- Lucas S. Kumosa
- Neuronano Research CenterDepartment of Experimental Medical ScienceMedical FacultyLund UniversityMedicon Village, Byggnad 404 A2, Scheelevägen 8Lund223 81Sweden
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7
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Yi D, Yao Y, Wang Y, Chen L. Manufacturing Processes of Implantable Microelectrode Array for In Vivo Neural Electrophysiological Recordings and Stimulation: A State-Of-the-Art Review. JOURNAL OF MICRO- AND NANO-MANUFACTURING 2022; 10:041001. [PMID: 37860671 PMCID: PMC10583290 DOI: 10.1115/1.4063179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/08/2023] [Indexed: 10/21/2023]
Abstract
Electrophysiological recording and stimulation of neuron activities are important for us to understand the function and dysfunction of the nervous system. To record/stimulate neuron activities as voltage fluctuation extracellularly, microelectrode array (MEA) implants are a promising tool to provide high temporal and spatial resolution for neuroscience studies and medical treatments. The design configuration and recording capabilities of the MEAs have evolved dramatically since their invention and manufacturing process development has been a key driving force for such advancement. Over the past decade, since the White House Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative launched in 2013, advanced manufacturing processes have enabled advanced MEAs with increased channel count and density, access to more brain areas, more reliable chronic performance, as well as minimal invasiveness and tissue reaction. In this state-of-the-art review paper, three major types of electrophysiological recording MEAs widely used nowadays, namely, microwire-based, silicon-based, and flexible MEAs are introduced and discussed. Conventional design and manufacturing processes and materials used for each type are elaborated, followed by a review of further development and recent advances in manufacturing technologies and the enabling new designs and capabilities. The review concludes with a discussion on potential future directions of manufacturing process development to enable the long-term goal of large-scale high-density brain-wide chronic recordings in freely moving animals.
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Affiliation(s)
- Dongyang Yi
- Department of Mechanical and Industrial Engineering, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854
| | - Yao Yao
- Department of Industrial and Systems Engineering, University of Missouri, 416 South 6th Street, Columbia, MO 65211
| | - Yi Wang
- Department of Industrial and Systems Engineering, University of Missouri, E3437C Thomas & Nell Lafferre Hall, 416 South 6th Street, Columbia, MO 65211
| | - Lei Chen
- Department of Mechanical and Industrial Engineering, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854
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8
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Chen PC, Young CG, Schaffer CB, Lal A. Ultrasonically actuated neural probes for reduced trauma and inflammation in mouse brain. MICROSYSTEMS & NANOENGINEERING 2022; 8:117. [PMID: 36341081 PMCID: PMC9626596 DOI: 10.1038/s41378-022-00438-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/13/2022] [Accepted: 07/08/2022] [Indexed: 06/16/2023]
Abstract
Electrical neural recordings measured using direct electrical interfaces with neural tissue suffer from a short lifespan because the signal strength decreases over time. The inflammatory response to the inserted microprobe can create insulating tissue over the electrical interfaces, reducing the recorded signal below noise levels. One of the factors contributing to this inflammatory response is the tissue damage caused during probe insertion. Here, we explore the use of ultrasonic actuation of the neural probe during insertion to minimize tissue damage in mice. Silicon neural microprobes were designed and fabricated with integrated electrical recording sites and piezoelectric transducers. The microprobes were actuated at ultrasonic frequencies using integrated piezoelectric transducers. The microprobes were inserted into mouse brains under a glass window over the brain surface to image the tissue surrounding the probe using two-photon microscopy. The mechanical force required to penetrate the tissue was reduced by a factor of 2-3 when the microprobe was driven at ultrasonic frequencies. Tissue histology at the probe insertion site showed a reduced area of damage and decreased microglia counts with increasing ultrasonic actuation of the probes. Two-photon imaging of the microprobe over weeks demonstrated stabilization of the inflammatory response. Recording of electrical signals from neurons over time suggests that microprobes inserted using ultrasound have a higher signal-to-noise ratio over an extended time period.
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Affiliation(s)
- Po-Cheng Chen
- SonicMEMS Laboratory, School of Electrical and Computer Engineering, Cornell University, Ithaca, NY USA
| | - Catharine G. Young
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY USA
| | - Chris B. Schaffer
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY USA
| | - Amit Lal
- SonicMEMS Laboratory, School of Electrical and Computer Engineering, Cornell University, Ithaca, NY USA
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9
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Geramifard N, Dousti B, Nguyen CK, Abbott JR, Cogan S, Varner V. Insertion mechanics of amorphous SiC ultra-micro scale neural probes. J Neural Eng 2022; 19. [PMID: 35263724 PMCID: PMC9339220 DOI: 10.1088/1741-2552/ac5bf4] [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: 10/14/2021] [Accepted: 03/09/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Trauma induced by the insertion of microelectrodes into cortical neural tissue is a significant problem. Further, micromotion and mechanical mismatch between microelectrode probes and neural tissue is implicated in an adverse foreign body response (FBR). Hence, intracortical ultra-microelectrode probes have been proposed as alternatives that minimize this FBR. However, significant challenges in implanting these flexible probes remain. We investigated the insertion mechanics of amorphous silicon carbide (a-SiC) probes with a view to defining probe geometries that can be inserted into cortex without buckling. APPROACH We determined the critical buckling force of a-SiC probes as a function of probe geometry and then characterized the buckling behavior of these probes by measuring force-displacement responses during insertion into agarose gel and rat cortex. MAIN RESULTS Insertion forces for a range of probe geometries were determined and compared with critical buckling forces to establish geometries that should avoid buckling during implantation into brain. The studies show that slower insertion speeds reduce the maximum insertion force for single-shank probes but increase cortical dimpling during insertion of multi-shank probes. SIGNIFICANCE Our results provide a guide for selecting probe geometries and insertion speeds that allow unaided implantation of probes into rat cortex. The design approach is applicable to other animal models where insertion of intracortical probes to a depth of 2 mm is required.
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Affiliation(s)
- Negar Geramifard
- Department of Bioeengineering, The University of Texas at Dallas Erik Jonsson School of Engineering and Computer Science, 800 West Campbell Rd., BSB 13.601, Richardson, Texas, 75080-3021, UNITED STATES
| | - Behnoush Dousti
- The University of Texas at Dallas, Department of Bioengineering, Richardson, Texas, 75080-3021, UNITED STATES
| | - Christopher Khanhtuan Nguyen
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, Texas, 75080-3021, UNITED STATES
| | - Justin Robert Abbott
- Department of Bioengineering, The University of Texas at Dallas, 800 West Campbell Rd, Richardson, Texas, 75080, UNITED STATES
| | - Stuart Cogan
- Department of Bioengineering, The University of Texas at Dallas Erik Jonsson School of Engineering and Computer Science, 800 West Campbell Road, Richardson, Texas, 75080-3021, UNITED STATES
| | - Victor Varner
- Department of Bioengineering, The University of Texas at Dallas Erik Jonsson School of Engineering and Computer Science, 800 West Campbell Rd, Richardson, Texas, 75080, UNITED STATES
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10
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Research Progress on the Flexibility of an Implantable Neural Microelectrode. MICROMACHINES 2022; 13:mi13030386. [PMID: 35334680 PMCID: PMC8954487 DOI: 10.3390/mi13030386] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/25/2021] [Accepted: 01/16/2022] [Indexed: 12/22/2022]
Abstract
Neural microelectrode is the important bridge of information exchange between the human body and machines. By recording and transmitting nerve signals with electrodes, people can control the external machines. At the same time, using electrodes to electrically stimulate nerve tissue, people with long-term brain diseases will be safely and reliably treated. Young’s modulus of the traditional rigid electrode probe is not matched well with that of biological tissue, and tissue immune rejection is easy to generate, resulting in the electrode not being able to achieve long-term safety and reliable working. In recent years, the choice of flexible materials and design of electrode structures can achieve modulus matching between electrode and biological tissue, and tissue damage is decreased. This review discusses nerve microelectrodes based on flexible electrode materials and substrate materials. Simultaneously, different structural designs of neural microelectrodes are reviewed. However, flexible electrode probes are difficult to implant into the brain. Only with the aid of certain auxiliary devices, can the implant be safe and reliable. The implantation method of the nerve microelectrode is also reviewed.
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11
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Otte E, Vlachos A, Asplund M. Engineering strategies towards overcoming bleeding and glial scar formation around neural probes. Cell Tissue Res 2022; 387:461-477. [PMID: 35029757 PMCID: PMC8975777 DOI: 10.1007/s00441-021-03567-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/17/2021] [Indexed: 12/15/2022]
Abstract
Neural probes are sophisticated electrophysiological tools used for intra-cortical recording and stimulation. These microelectrode arrays, designed to penetrate and interface the brain from within, contribute at the forefront of basic and clinical neuroscience. However, one of the challenges and currently most significant limitations is their ‘seamless’ long-term integration into the surrounding brain tissue. Following implantation, which is typically accompanied by bleeding, the tissue responds with a scarring process, resulting in a gliotic region closest to the probe. This glial scarring is often associated with neuroinflammation, neurodegeneration, and a leaky blood–brain interface (BBI). The engineering progress on minimizing this reaction in the form of improved materials, microfabrication, and surgical techniques is summarized in this review. As research over the past decade has progressed towards a more detailed understanding of the nature of this biological response, it is time to pose the question: Are penetrating probes completely free from glial scarring at all possible?
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12
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Roh H, Yoon YJ, Park JS, Kang DH, Kwak SM, Lee BC, Im M. Fabrication of High-Density Out-of-Plane Microneedle Arrays with Various Heights and Diverse Cross-Sectional Shapes. NANO-MICRO LETTERS 2021; 14:24. [PMID: 34888758 PMCID: PMC8656445 DOI: 10.1007/s40820-021-00778-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/16/2021] [Indexed: 06/01/2023]
Abstract
Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine interface. This work presents a novel but simple method to fabricate high-density silicon (Si) microneedle arrays with various heights and diverse cross-sectional shapes depending on photomask pattern designs. The proposed fabrication method is composed of a single photolithography and two subsequent deep reactive ion etching (DRIE) steps. First, a photoresist layer was patterned on a Si substrate to define areas to be etched, which will eventually determine the final location and shape of each individual microneedle. Then, the 1st DRIE step created deep trenches with a highly anisotropic etching of the Si substrate. Subsequently, the photoresist was removed for more isotropic etching; the 2nd DRIE isolated and sharpened microneedles from the predefined trench structures. Depending on diverse photomask designs, the 2nd DRIE formed arrays of microneedles that have various height distributions, as well as diverse cross-sectional shapes across the substrate. With these simple steps, high-aspect ratio microneedles were created in the high density of up to 625 microneedles mm-2 on a Si wafer. Insertion tests showed a small force as low as ~ 172 µN/microneedle is required for microneedle arrays to penetrate the dura mater of a mouse brain. To demonstrate a feasibility of drug delivery application, we also implemented silk microneedle arrays using molding processes. The fabrication method of the present study is expected to be broadly applicable to create microneedle structures for drug delivery, neuroprosthetic devices, and so on.
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Affiliation(s)
- Hyeonhee Roh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
- Division of Electrical Engineering, College of Engineering, Korea University, Seoul, 02841, South Korea
| | - Young Jun Yoon
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
| | - Jin Soo Park
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
- Division of Electrical Engineering, College of Engineering, Korea University, Seoul, 02841, South Korea
| | - Dong-Hyun Kang
- Micro/Nano Fabrication Center, KIST, Seoul, 02792, South Korea
| | - Seung Min Kwak
- Micro/Nano Fabrication Center, KIST, Seoul, 02792, South Korea
| | - Byung Chul Lee
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
| | - Maesoon Im
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea.
- Division of Bio-Medical Science & Technology, KIST School, University of Science & Technology (UST), Seoul, 02792, South Korea.
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13
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Darayi M, Hoffman ME, Sayut J, Wang S, Demirci N, Consolini J, Holland MA. Computational models of cortical folding: A review of common approaches. J Biomech 2021; 139:110851. [PMID: 34802706 DOI: 10.1016/j.jbiomech.2021.110851] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 08/09/2021] [Accepted: 10/26/2021] [Indexed: 11/29/2022]
Abstract
The process of gyrification, by which the brain develops the intricate pattern of gyral hills and sulcal valleys, is the result of interactions between biological and mechanical processes during brain development. Researchers have developed a vast array of computational models in order to investigate cortical folding. This review aims to summarize these studies, focusing on five essential elements of the brain that affect development and gyrification and how they are represented in computational models: (i) the constraints of skull, meninges, and cerebrospinal fluid; (ii) heterogeneity of cortical layers and regions; (iii) anisotropic behavior of subcortical fiber tracts; (iv) material properties of brain tissue; and (v) the complex geometry of the brain. Finally, we highlight areas of need for future simulations of brain development.
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Affiliation(s)
- Mohsen Darayi
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Mia E Hoffman
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - John Sayut
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Shuolun Wang
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Nagehan Demirci
- Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Jack Consolini
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Maria A Holland
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA; Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA.
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14
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Jamal A, Bernardini A, Dini D. Microscale characterisation of the time-dependent mechanical behaviour of brain white matter. J Mech Behav Biomed Mater 2021; 125:104917. [PMID: 34710852 DOI: 10.1016/j.jmbbm.2021.104917] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/06/2021] [Accepted: 10/16/2021] [Indexed: 01/08/2023]
Abstract
Brain mechanics is a topic of deep interest because of the significant role of mechanical cues in both brain function and form. Specifically, capturing the heterogeneous and anisotropic behaviour of cerebral white matter (WM) is extremely challenging and yet the data on WM at a spatial resolution relevant to tissue components are sparse. To investigate the time-dependent mechanical behaviour of WM, and its dependence on local microstructural features when subjected to small deformations, we conducted atomic force microscopy (AFM) stress relaxation experiments on corpus callosum (CC), corona radiata (CR) and fornix (FO) of fresh ovine brain. Our experimental results show a dependency of the tissue mechanical response on axons orientation, with e.g. the stiffness of perpendicular and parallel samples is different in all three regions of WM whereas the relaxation behaviour is different for the CC and FO regions. An inverse modelling approach was adopted to extract Prony series parameters of the tissue components, i.e. axons and extra cellular matrix with its accessory cells, from experimental data. Using a bottom-up approach, we developed analytical and FEA estimates that are in good agreement with our experimental results. Our systematic characterisation of sheep brain WM using a combination of AFM experiments and micromechanical models provide a significant contribution for predicting localised time-dependent mechanics of brain tissue. This information can lead to more accurate computational simulations, therefore aiding the development of surgical robotic solutions for drug delivery and accurate tissue mimics, as well as the determination of criteria for tissue injury and predict brain development and disease progression.
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Affiliation(s)
- Asad Jamal
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK.
| | - Andrea Bernardini
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK
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15
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Kumosa LS, Schouenborg J. Profound alterations in brain tissue linked to hypoxic episode after device implantation. Biomaterials 2021; 278:121143. [PMID: 34653937 DOI: 10.1016/j.biomaterials.2021.121143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/20/2021] [Indexed: 12/17/2022]
Abstract
To enable authentic interfacing with neuronal structures in the brain, preventing alterations of tissue during implantation of devices is critical. By transiently implanting oxygen microsensors into rat cortex cerebri for 2 h, substantial and long lasting (>1 h) hypoxia is routinely generated in surrounding tissues; this hypoxia is linked to implantation generated compressive forces. Preferential loss of larger neurons and reduced metabolic components in surviving neurons indicates decreased viability one week after such hypoxic, compressive implantations. By devising an implantation method that relaxes compressive forces; magnitude and duration of hypoxia generated following such an implantation are ameliorated and neurons appear similar to naïve tissues. In line with these observations, astrocyte proliferation was significantly more pronounced for more hypoxic, compressive implantations. Surprisingly, astrocyte processes were frequently found to traverse cellular boundaries into nearby neuronal nuclei, indicating injury induction of a previously not described astrocyte-neuron interaction. Found more frequently in less hypoxic, force-relaxed insertions and thus correlating to a more beneficial outcome, this finding may suggest a novel protective mechanism. In conclusion, substantial and long lasting insertion induced hypoxia around brain implants, a previously overlooked factor, is linked to significant adverse alterations in nervous tissue.
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Affiliation(s)
- Lucas S Kumosa
- Neuronano Research Center, Faculty of Medicine, Lund University, Scheelevägen 2, Medicon Village 404A2, 223 81, Lund, Sweden.
| | - Jens Schouenborg
- Neuronano Research Center, Faculty of Medicine, Lund University, Scheelevägen 2, Medicon Village 404A2, 223 81, Lund, Sweden; NanoLund, Lund University, Professorsgatan 1, 223 63, Lund, Sweden.
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16
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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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17
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Chen L, Hartner J, Dong T, Li A, Watson B, Shih A. Flexible High-Resolution Force and Dimpling Measurement System for Pia and Dura Penetration During In Vivo Microelectrode Insertion Into Rat Brain. IEEE Trans Biomed Eng 2021; 68:2602-2612. [PMID: 33798065 PMCID: PMC8323825 DOI: 10.1109/tbme.2021.3070781] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Understanding the in vivo force and tissue dimpling during micro-electrode implantation into the brain are important for neuro-electrophysiology to minimize damage while enabling accurate placement and stable chronic extracellular electrophysiological recordings. Prior studies were unable to measure the sub-mN forces exerted during in vivo insertion of small electrodes. Here, we have investigated the in vivo force and dimpling depth profiles during brain surface membrane rupture (including dura) in anesthetized rats. METHODS A μN-resolution cantilever beam-based measurement system was designed, built, and calibrated and adapted for in vivo use. A total of 244 in vivo insertion tests were conducted on 8 anesthetized rats with 121 through pia mater and 123 through dura and pia combined. RESULTS Both microwire tip sharpening and diameter reduction reduced membrane rupture force (insertion force) and eased brain surface penetration. But dimpling depth and rupture force are not always strongly correlated. Multi-shank silicon probes showed smaller dimpling and rupture force per shank than single shank devices. CONCLUSION A force measurement system with flexible range and μN-level resolution (up to 0.032 μN) was achieved and proved feasible. For both pia-only and dura-pia penetrations in anesthetized rats, the rupture force and membrane dimpling depth at rupture are linearly related to the microwire diameter. SIGNIFICANCE We have developed a new system with both μN-level resolution and capacity to be used in vivo for measurement of force profiles of various neural interfaces into the brain. This allows quantification of brain tissue cutting and provides design guidelines for optimal neural interfaces.
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18
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Pimenta S, Rodrigues JA, Machado F, Ribeiro JF, Maciel MJ, Bondarchuk O, Monteiro P, Gaspar J, Correia JH, Jacinto L. Double-Layer Flexible Neural Probe With Closely Spaced Electrodes for High-Density in vivo Brain Recordings. Front Neurosci 2021; 15:663174. [PMID: 34211364 PMCID: PMC8239195 DOI: 10.3389/fnins.2021.663174] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/19/2021] [Indexed: 11/13/2022] Open
Abstract
Flexible polymer neural probes are an attractive emerging approach for invasive brain recordings, given that they can minimize the risks of brain damage or glial scaring. However, densely packed electrode sites, which can facilitate neuronal data analysis, are not widely available in flexible probes. Here, we present a new flexible polyimide neural probe, based on standard and low-cost lithography processes, which has 32 closely spaced 10 μm diameter gold electrode sites at two different depths from the probe surface arranged in a matrix, with inter-site distances of only 5 μm. The double-layer design and fabrication approach implemented also provides additional stiffening just sufficient to prevent probe buckling during brain insertion. This approach avoids typical laborious augmentation strategies used to increase flexible probes’ mechanical rigidity while allowing a small brain insertion footprint. Chemical composition analysis and metrology of structural, mechanical, and electrical properties demonstrated the viability of this fabrication approach. Finally, in vivo functional assessment tests in the mouse cortex were performed as well as histological assessment of the insertion footprint, validating the biological applicability of this flexible neural probe for acquiring high quality neuronal recordings with high signal to noise ratio (SNR) and reduced acute trauma.
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Affiliation(s)
- Sara Pimenta
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimarães, Portugal
| | - José A Rodrigues
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimarães, Portugal
| | - Francisca Machado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - João F Ribeiro
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimarães, Portugal
| | - Marino J Maciel
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimarães, Portugal
| | | | - Patricia Monteiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - João Gaspar
- International Iberian Nanotechnology Laboratory (INL), Braga, Portugal
| | - José H Correia
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimarães, Portugal
| | - Luis Jacinto
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
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19
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Thielen B, Meng E. A comparison of insertion methods for surgical placement of penetrating neural interfaces. J Neural Eng 2021; 18:10.1088/1741-2552/abf6f2. [PMID: 33845469 PMCID: PMC8600966 DOI: 10.1088/1741-2552/abf6f2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/12/2021] [Indexed: 02/07/2023]
Abstract
Many implantable electrode arrays exist for the purpose of stimulating or recording electrical activity in brain, spinal, or peripheral nerve tissue, however most of these devices are constructed from materials that are mechanically rigid. A growing body of evidence suggests that the chronic presence of these rigid probes in the neural tissue causes a significant immune response and glial encapsulation of the probes, which in turn leads to gradual increase in distance between the electrodes and surrounding neurons. In recording electrodes, the consequence is the loss of signal quality and, therefore, the inability to collect electrophysiological recordings long term. In stimulation electrodes, higher current injection is required to achieve a comparable response which can lead to tissue and electrode damage. To minimize the impact of the immune response, flexible neural probes constructed with softer materials have been developed. These flexible probes, however, are often not strong enough to be inserted on their own into the tissue, and instead fail via mechanical buckling of the shank under the force of insertion. Several strategies have been developed to allow the insertion of flexible probes while minimizing tissue damage. It is critical to keep these strategies in mind during probe design in order to ensure successful surgical placement. In this review, existing insertion strategies will be presented and evaluated with respect to surgical difficulty, immune response, ability to reach the target tissue, and overall limitations of the technique. Overall, the majority of these insertion techniques have only been evaluated for the insertion of a single probe and do not quantify the accuracy of probe placement. More work needs to be performed to evaluate and optimize insertion methods for accurate placement of devices and for devices with multiple probes.
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Affiliation(s)
- Brianna Thielen
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States of America
| | - Ellis Meng
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States of America
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20
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Carnicer-Lombarte A, Chen ST, Malliaras GG, Barone DG. Foreign Body Reaction to Implanted Biomaterials and Its Impact in Nerve Neuroprosthetics. Front Bioeng Biotechnol 2021; 9:622524. [PMID: 33937212 PMCID: PMC8081831 DOI: 10.3389/fbioe.2021.622524] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/19/2021] [Indexed: 12/04/2022] Open
Abstract
The implantation of any foreign material into the body leads to the development of an inflammatory and fibrotic process-the foreign body reaction (FBR). Upon implantation into a tissue, cells of the immune system become attracted to the foreign material and attempt to degrade it. If this degradation fails, fibroblasts envelop the material and form a physical barrier to isolate it from the rest of the body. Long-term implantation of medical devices faces a great challenge presented by FBR, as the cellular response disrupts the interface between implant and its target tissue. This is particularly true for nerve neuroprosthetic implants-devices implanted into nerves to address conditions such as sensory loss, muscle paralysis, chronic pain, and epilepsy. Nerve neuroprosthetics rely on tight interfacing between nerve tissue and electrodes to detect the tiny electrical signals carried by axons, and/or electrically stimulate small subsets of axons within a nerve. Moreover, as advances in microfabrication drive the field to increasingly miniaturized nerve implants, the need for a stable, intimate implant-tissue interface is likely to quickly become a limiting factor for the development of new neuroprosthetic implant technologies. Here, we provide an overview of the material-cell interactions leading to the development of FBR. We review current nerve neuroprosthetic technologies (cuff, penetrating, and regenerative interfaces) and how long-term function of these is limited by FBR. Finally, we discuss how material properties (such as stiffness and size), pharmacological therapies, or use of biodegradable materials may be exploited to minimize FBR to nerve neuroprosthetic implants and improve their long-term stability.
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Affiliation(s)
- Alejandro Carnicer-Lombarte
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Shao-Tuan Chen
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - George G. Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Damiano G. Barone
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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21
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Golahmadi AK, Khan DZ, Mylonas GP, Marcus HJ. Tool-tissue forces in surgery: A systematic review. Ann Med Surg (Lond) 2021; 65:102268. [PMID: 33898035 PMCID: PMC8058906 DOI: 10.1016/j.amsu.2021.102268] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 11/30/2022] Open
Abstract
Background Excessive tool-tissue interaction forces often result in tissue damage and intraoperative complications, while insufficient forces prevent the completion of the task. This review sought to explore the tool-tissue interaction forces exerted by instruments during surgery across different specialities, tissues, manoeuvres and experience levels. Materials & methods A PRISMA-guided systematic review was carried out using Embase, Medline and Web of Science databases. Results Of 462 articles screened, 45 studies discussing surgical tool-tissue forces were included. The studies were categorized into 9 different specialities with the mean of average forces lowest for ophthalmology (0.04N) and highest for orthopaedic surgery (210N). Nervous tissue required the least amount of force to manipulate (mean of average: 0.4N), whilst connective tissue (including bone) required the most (mean of average: 45.8). For manoeuvres, drilling recorded the highest forces (mean of average: 14N), whilst sharp dissection recorded the lowest (mean of average: 0.03N). When comparing differences in the mean of average forces between groups, novices exerted 22.7% more force than experts, and presence of a feedback mechanism (e.g. audio) reduced exerted forces by 47.9%. Conclusions The measurement of tool-tissue forces is a novel but rapidly expanding field. The range of forces applied varies according to surgical speciality, tissue, manoeuvre, operator experience and feedback provided. Knowledge of the safe range of surgical forces will improve surgical safety whilst maintaining effectiveness. Measuring forces during surgery may provide an objective metric for training and assessment. Development of smart instruments, robotics and integrated feedback systems will facilitate this. This review explores tool-tissue forces during surgery, a new and expanding field. Forces were lowest in ophthalmology (0.04N) and highest in orthopaedics (210N). Forces were lowest during sharp dissection (0.03N) and highest when drilling (14N). Being an expert (vs. novice) and having feedback mechanisms (e.g. haptic) reduced exerted forces. Development of force metrics will facilitate training, assessment & novel technology.
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Affiliation(s)
- Aida Kafai Golahmadi
- Imperial College London School of Medicine, London, United Kingdom.,HARMS Laboratory, The Hamlyn Centre, Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Danyal Z Khan
- National Hospital for Neurology and Neurosurgery, London, United Kingdom.,Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, United Kingdom
| | - George P Mylonas
- HARMS Laboratory, The Hamlyn Centre, Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Hani J Marcus
- National Hospital for Neurology and Neurosurgery, London, United Kingdom.,Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, United Kingdom
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22
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Atkinson D, D'Souza T, Rajput JS, Tasnim N, Muthuswamy J, Marvi H, Pancrazio JJ. Advances in Implantable Microelectrode Array Insertion and Positioning. Neuromodulation 2021; 25:789-795. [PMID: 33438369 DOI: 10.1111/ner.13355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/14/2020] [Accepted: 12/21/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Microelectrode arrays offer a means to probe the functional circuitry of the brain and the promise of cortical neuroprosthesis for individuals suffering from paralysis or limb loss. These devices are typically comprised of one or more shanks incorporating microelectrode sites, where the shanks are positioned by inserting the devices along a straight path that is normal to the brain surface. The lack of consistent long-term chronic recording technology has driven interest in novel probe design and approaches that go beyond the standard insertion approach that is limited to a single velocity or axis. This review offers a description of typical approaches and associated limitations and surveys emergent methods for implantation of microelectrode arrays, in particular those new approaches that leverage embedded microactuators and extend the insertion direction beyond a single axis. MATERIALS AND METHODS This review paper surveys the current technologies that enable probe implantation, repositioning, and the capability to record/stimulate from a tissue volume. A comprehensive literature search was performed using PubMed, Web of Science, and Google Scholar. RESULTS There has been substantial innovation in the development of microscale and embedded technology that enables probe repositioning to maintain quality recordings in the brain. Innovations in material science have resulted in novel strategies for deployable structures that can record from or stimulate a tissue volume. Moreover, new developments involving magnetically steerable catheters and needles offer an alternative approach to "pull" rather than "push" a probe into the tissue. CONCLUSION We envision the emergence of a new generation of probes and insertion methodologies for neuromodulation applications that enable reliable chronic performance from devices that can be positioned virtually anywhere in the brain.
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Affiliation(s)
- David Atkinson
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Tania D'Souza
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Jai Singh Rajput
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Nishat Tasnim
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Jit Muthuswamy
- Department of Biomedical Engineering, School of Biological and Health Systems, Engineering, Arizona State University, Tempe, AZ, USA
| | - Hamid Marvi
- School for Engineering of Matter Transport and Energy, Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, AZ, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
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23
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Dong T, Chen L, Shih A. Laser Sharpening of Carbon Fiber Microelectrode Arrays for Brain Recording. JOURNAL OF MICRO- AND NANO-MANUFACTURING 2020; 8:041013. [PMID: 35833189 PMCID: PMC8597551 DOI: 10.1115/1.4049780] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 01/11/2021] [Indexed: 06/15/2023]
Abstract
Microwire microelectrode arrays (MEAs) are implanted in the brain for recording neuron activities to study the brain function. Among various microwire materials, carbon fiber stands out due to its small diameter (5-10 μm), relatively high Young's modulus, and low electrical resistance. Microwire tips in MEAs are often sharpened to reduce the insertion force and prevent the thin microwires from buckling. Currently, carbon fiber MEAs are sharpened by either torch burning, which limits the positions of wire tips to a water bath surface plane, or electrical discharge machining, which is difficult to implement to the nonelectrically conductive carbon fiber with parylene-C insulation. A laser-based carbon fiber sharpening method proposed in this study enables the fabrication of carbon fiber MEAs with sharp tips and custom lengths. Experiments were conducted to study effects of laser input voltage and transverse speed on carbon fiber tip geometry. Results of the tip sharpness and stripped length of the insulation as well as the electrochemical impedance spectroscopy measurement at 1 kHz were evaluated and analyzed. The laser input voltage and traverse speed have demonstrated to be critical for the sharp tip, short stripped length, and low electrical impedance of the carbon fiber electrode for brain recording MEAs. A carbon fiber MEA with custom electrode lengths was fabricated to validate the laser-based approach.
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Affiliation(s)
- Tianshu Dong
- Mechanical Engineering, University of Michigan, 2370 GG Brown, 2350 Hayward Street, Ann Arbor, MI 48109
| | - Lei Chen
- Mechanical Engineering, University of Massachusetts Lowell, Dandeneau Hall 231, 1 University Ave., Lowell, MA 01854
| | - Albert Shih
- Mechanical Engineering, Biomedical Engineering, University of Michigan, 3001E EECS, 1301 Beal Ave., Ann Arbor, MI 48109
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24
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Belanger MC, Anbaei P, Dunn AF, Kinman AW, Pompano RR. Spatially Resolved Analytical Chemistry in Intact, Living Tissues. Anal Chem 2020; 92:15255-15262. [PMID: 33201681 PMCID: PMC7864589 DOI: 10.1021/acs.analchem.0c03625] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tissues are an exciting frontier for bioanalytical chemistry, one in which spatial distribution is just as important as total content. Intact tissue preserves the native cellular and molecular organization and the cell-cell contacts found in vivo. Live tissue, in particular, offers the potential to analyze dynamic events in a spatially resolved manner, leading to fundamental biological insights and translational discoveries. In this Perspective, we provide a tutorial on the four fundamental challenges for the bioanalytical chemist working in living tissue samples as well as best practices for mitigating them. The challenges include (i) the complexity of the sample matrix, which contributes myriad interfering species and causes nonspecific binding of reagents; (ii) hindered delivery and mixing; (iii) the need to maintain physiological conditions; and (iv) tissue reactivity. This framework is relevant to a variety of methods for spatially resolved chemical analysis, including optical imaging, inserted sensors and probes such as electrodes, and surface analyses such as sensing arrays. The discussion focuses primarily on ex vivo tissues, though many considerations are relevant in vivo as well. Our goal is to convey the exciting potential of analytical chemistry to contribute to understanding the functions of live, intact tissues.
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Affiliation(s)
- Maura C. Belanger
- Department of Chemistry, University of Virginia, PO BOX 400319, Charlottesville, VA 22904
| | - Parastoo Anbaei
- Department of Chemistry, University of Virginia, PO BOX 400319, Charlottesville, VA 22904
| | - Austin F. Dunn
- Department of Chemistry, University of Virginia, PO BOX 400319, Charlottesville, VA 22904
| | - Andrew W.L. Kinman
- Department of Chemistry, University of Virginia, PO BOX 400319, Charlottesville, VA 22904
| | - Rebecca R. Pompano
- Department of Chemistry, University of Virginia, PO BOX 400319, Charlottesville, VA 22904
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25
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Cieśluk M, Pogoda K, Deptuła P, Werel P, Kułakowska A, Kochanowicz J, Mariak Z, Łysoń T, Reszeć J, Bucki R. Nanomechanics and Histopathology as Diagnostic Tools to Characterize Freshly Removed Human Brain Tumors. Int J Nanomedicine 2020; 15:7509-7521. [PMID: 33116485 PMCID: PMC7547774 DOI: 10.2147/ijn.s270147] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/18/2020] [Indexed: 12/28/2022] Open
Abstract
Background The tissue-mechanics environment plays a crucial role in human brain physiological development and the pathogenesis of different diseases, especially cancer. Assessment of alterations in brain mechanical properties during cancer progression might provide important information about possible tissue abnormalities with clinical relevance. Methods With atomic force microscopy (AFM), the stiffness of freshly removed human brain tumor tissue was determined on various regions of the sample and compared to the stiffness of healthy human brain tissue that was removed during neurosurgery to gain access to tumor mass. An advantage of indentation measurement using AFM is the small volume of tissue required and high resolution at the single-cell level. Results Our results showed great heterogeneity of stiffness within metastatic cancer or primary high-grade gliomas compared to healthy tissue. That effect was not clearly visible in lower-grade tumors like meningioma. Conclusion Collected data indicate that AFM might serve as a diagnostic tool in the assessment of human brain tissue stiffness in the process of recognizing tumors.
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Affiliation(s)
- Mateusz Cieśluk
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok PL-15222, Poland
| | - Katarzyna Pogoda
- Institute of Nuclear Physics, Polish Academy of Sciences, Krakow PL-31342, Poland
| | - Piotr Deptuła
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok PL-15222, Poland
| | - Paulina Werel
- Department of Neurology, Medical University of Bialystok, Bialystok PL-15276, Poland
| | - Alina Kułakowska
- Department of Neurology, Medical University of Bialystok, Bialystok PL-15276, Poland
| | - Jan Kochanowicz
- Department of Neurology, Medical University of Bialystok, Bialystok PL-15276, Poland
| | - Zenon Mariak
- Department of Neurosurgery, Medical University of Bialystok, Bialystok PL-15276, Poland
| | - Tomasz Łysoń
- Department of Neurosurgery, Medical University of Bialystok, Bialystok PL-15276, Poland
| | - Joanna Reszeć
- Department of Pathology, Medical University of Bialystok, Bialystok PL-15269, Poland
| | - Robert Bucki
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok PL-15222, Poland
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Mohammed M, Thelin J, Gällentoft L, Thorbergsson PT, Kumosa LS, Schouenborg J, Pettersson LME. Ice coating -A new method of brain device insertion to mitigate acute injuries. J Neurosci Methods 2020; 343:108842. [PMID: 32628965 DOI: 10.1016/j.jneumeth.2020.108842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/22/2020] [Accepted: 07/02/2020] [Indexed: 01/12/2023]
Abstract
BACKGROUND Reduction of insertion injury is likely important to approach physiological conditions in the vicinity of implanted devices intended to interface with the surrounding brain. NEW METHODS We have developed a novel, low-friction coating around frozen, gelatin embedded needles. By introducing a layer of thawing ice onto the gelatin, decreasing surface friction, we mitigate damage caused by the implantation. RESULTS AND COMPARISON WITH EXISTING METHODS The acute effects of a transient stab on neuronal density and glial reactions were assessed 1 and 7 days post stab in rat cortex and striatum both within and outside the insertion track using immunohistochemical staining. The addition of a coat of melting ice to the frozen gelatin embedded needles reduced the insertion force with around 50 %, substantially reduced the loss neurons (i.e. reduced neuronal void), and yielded near normal levels of astrocytes within the insertion track 1 day after insertion, as compared to gelatin coated probes of the same temperature without ice coating. There were negligible effects on glial reactions and neuronal density immediately outside the insertion track of both ice coated and cold gelatin embedded needles. This new method of implantation presents a considerable improvement compared to existing modes of device insertion. CONCLUSIONS Acute brain injuries following insertion of e.g. ultra-flexible electrodes, can be reduced by providing an outer coat of ultra-slippery thawing ice. No adverse effect of lowered implant temperature was found, opening the possibility of locking fragile electrode construct configurations in frozen gelatin, prior to implantation into the brain.
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Affiliation(s)
- Mohsin Mohammed
- Neuronano Research Center, Department of Experimental Medicine, Lund University, Lund, Sweden.
| | - Jonas Thelin
- Neuronano Research Center, Department of Experimental Medicine, Lund University, Lund, Sweden
| | - Lina Gällentoft
- Neuronano Research Center, Department of Experimental Medicine, Lund University, Lund, Sweden
| | - Palmi Thor Thorbergsson
- Neuronano Research Center, Department of Experimental Medicine, Lund University, Lund, Sweden
| | - Lucas S Kumosa
- Neuronano Research Center, Department of Experimental Medicine, Lund University, Lund, Sweden
| | - Jens Schouenborg
- Neuronano Research Center, Department of Experimental Medicine, Lund University, Lund, Sweden; NanoLund, Lund University, Professorsgatan 1, SE-223 63, Lund, Sweden
| | - Lina M E Pettersson
- Neuronano Research Center, Department of Experimental Medicine, Lund University, Lund, Sweden; NanoLund, Lund University, Professorsgatan 1, SE-223 63, Lund, Sweden.
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He F, Lycke R, Ganji M, Xie C, Luan L. Ultraflexible Neural Electrodes for Long-Lasting Intracortical Recording. iScience 2020; 23:101387. [PMID: 32745989 PMCID: PMC7398974 DOI: 10.1016/j.isci.2020.101387] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 06/22/2020] [Accepted: 07/16/2020] [Indexed: 11/16/2022] Open
Abstract
Implanted electrodes provide one of the most important neurotechniques for fundamental and translational neurosciences by permitting time-resolved electrical detection of individual neurons in vivo. However, conventional rigid electrodes typically cannot provide stable, long-lasting recordings. Numerous interwoven biotic and abiotic factors at the tissue-electrode interface lead to short- and long-term instability of the recording performance. Making neural electrodes flexible provides a promising approach to mitigate these challenges on the implants and at the tissue-electrode interface. Here we review the recent progress of ultraflexible neural electrodes and discuss the engineering principles, the material properties, and the implantation strategies to achieve stable tissue-electrode interface and reliable unit recordings in living brains.
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Affiliation(s)
- Fei He
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA
| | - Roy Lycke
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA; Department of Biomedical Engineering, University of Texas at Austin, 107 Dean Keeton, Austin, TX 78712, USA
| | - Mehran Ganji
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA; Department of Biomedical Engineering, University of Texas at Austin, 107 Dean Keeton, Austin, TX 78712, USA
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA; Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Lan Luan
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA; Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA.
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Kollo M, Racz R, Hanna ME, Obaid A, Angle MR, Wray W, Kong Y, Müller J, Hierlemann A, Melosh NA, Schaefer AT. CHIME: CMOS-Hosted in vivo Microelectrodes for Massively Scalable Neuronal Recordings. Front Neurosci 2020; 14:834. [PMID: 32848584 PMCID: PMC7432274 DOI: 10.3389/fnins.2020.00834] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 07/16/2020] [Indexed: 01/20/2023] Open
Abstract
Mammalian brains consist of 10s of millions to 100s of billions of neurons operating at millisecond time scales, of which current recording techniques only capture a tiny fraction. Recording techniques capable of sampling neural activity at high spatiotemporal resolution have been difficult to scale. The most intensively studied mammalian neuronal networks, such as the neocortex, show a layered architecture, where the optimal recording technology samples densely over large areas. However, the need for application-specific designs as well as the mismatch between the three-dimensional architecture of the brain and largely two-dimensional microfabrication techniques profoundly limits both neurophysiological research and neural prosthetics. Here, we discuss a novel strategy for scalable neuronal recording by combining bundles of glass-ensheathed microwires with large-scale amplifier arrays derived from high-density CMOS in vitro MEA systems or high-speed infrared cameras. High signal-to-noise ratio (<25 μV RMS noise floor, SNR up to 25) is achieved due to the high conductivity of core metals in glass-ensheathed microwires allowing for ultrathin metal cores (down to <1 μm) and negligible stray capacitance. Multi-step electrochemical modification of the tip enables ultra-low access impedance with minimal geometric area, which is largely independent of the core diameter. We show that the microwire size can be reduced to virtually eliminate damage to the blood-brain-barrier upon insertion and we demonstrate that microwire arrays can stably record single-unit activity. Combining microwire bundles and CMOS arrays allows for a highly scalable neuronal recording approach, linking the progress in electrical neuronal recordings to the rapid progress in silicon microfabrication. The modular design of the system allows for custom arrangement of recording sites. Our approach of employing bundles of minimally invasive, highly insulated and functionalized microwires to extend a two-dimensional CMOS architecture into the 3rd dimension can be translated to other CMOS arrays, such as electrical stimulation devices.
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Affiliation(s)
- Mihaly Kollo
- Neurophysiology of Behaviour Laboratory, Francis Crick Institute, London, United Kingdom
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Romeo Racz
- Neurophysiology of Behaviour Laboratory, Francis Crick Institute, London, United Kingdom
| | - Mina-Elraheb Hanna
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, United States
- Paradromics, Inc., Austin, TX, United States
| | - Abdulmalik Obaid
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, United States
| | | | - William Wray
- Neurophysiology of Behaviour Laboratory, Francis Crick Institute, London, United Kingdom
| | - Yifan Kong
- Paradromics, Inc., Austin, TX, United States
| | - Jan Müller
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
- MaxWell Biosystems AG, Zurich, Switzerland
| | - Andreas Hierlemann
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
| | - Nicholas A. Melosh
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, United States
| | - Andreas T. Schaefer
- Neurophysiology of Behaviour Laboratory, Francis Crick Institute, London, United Kingdom
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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Wang X, Weltman Hirschberg A, Xu H, Slingsby-Smith Z, Lecomte A, Scholten K, Song D, Meng E. A Parylene Neural Probe Array for Multi-Region Deep Brain Recordings. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2020; 29:499-513. [PMID: 35663261 PMCID: PMC9164222 DOI: 10.1109/jmems.2020.3000235] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A Parylene C polymer neural probe array with 64 electrodes purposefully positioned across 8 individual shanks to anatomically match specific regions of the hippocampus was designed, fabricated, characterized, and implemented in vivo for enabling recording in deep brain regions in freely moving rats. Thin film polymer arrays were fabricated using surface micromachining techniques and mechanically braced to prevent buckling during surgical implantation. Importantly, the mechanical bracing technique developed in this work involves a novel biodegradable polymer brace that temporarily reduces shank length and consequently, increases its stiffness during implantation, therefore enabling access to deeper brain regions while preserving a low original cross-sectional area of the shanks. The resulting mechanical properties of braced shanks were evaluated at the benchtop. Arrays were then implemented in vivo in freely moving rats, achieving both acute and chronic recordings from the pyramidal cells in the cornu ammonis (CA) 1 and CA3 regions of the hippocampus which are responsible for memory encoding. This work demonstrated the potential for minimally invasive polymer-based neural probe arrays for multi-region recording in deep brain structures.
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Affiliation(s)
- Xuechun Wang
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | | | - Huijing Xu
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | | | - Aziliz Lecomte
- Fondazione Istituto Italiano di Technologia, 16163 Genova, Italy
| | - Kee Scholten
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | - Dong Song
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | - Ellis Meng
- Biomedical Engineering and Electrical and Computer Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
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Sung C, Jeon W, Nam KS, Kim Y, Butt H, Park S. Multimaterial and multifunctional neural interfaces: from surface-type and implantable electrodes to fiber-based devices. J Mater Chem B 2020; 8:6624-6666. [DOI: 10.1039/d0tb00872a] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Development of neural interfaces from surface electrodes to fibers with various type, functionality, and materials.
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Affiliation(s)
- Changhoon Sung
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Woojin Jeon
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Kum Seok Nam
- School of Electrical Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Yeji Kim
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Haider Butt
- Department of Mechanical Engineering
- Khalifa University
- Abu Dhabi 127788
- United Arab Emirates
| | - Seongjun Park
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
- KAIST Institute for Health Science and Technology (KIHST)
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31
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Golabchi A, Wu B, Cao B, Bettinger CJ, Cui XT. Zwitterionic polymer/polydopamine coating reduce acute inflammatory tissue responses to neural implants. Biomaterials 2019; 225:119519. [PMID: 31600673 PMCID: PMC6896321 DOI: 10.1016/j.biomaterials.2019.119519] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 09/17/2019] [Accepted: 09/23/2019] [Indexed: 12/13/2022]
Abstract
The inflammatory brain tissue response to implanted neural electrode devices has hindered the longevity of these implants. Zwitterionic polymers have a potent anti-fouling effect that decreases the foreign body response to subcutaneous implants. In this study, we developed a nanoscale anti-fouling coating composed of zwitterionic poly (sulfobetaine methacrylate) (PSB) and polydopamine (PDA) for neural probes. The addition of PDA improved the stability of the coating compared to PSB alone, without compromising the anti-fouling properties of the film. PDA-PSB coating reduced protein adsorption by 89% compared to bare Si samples, while fibroblast adhesion was reduced by 86%. PDA-PSB coated silicon based neural probes were implanted into mouse brain, and the inflammatory tissue responses to the implants were assessed by immunohistochemistry one week after implantation. The PSB-PDA coated implants showed a significantly decreased expression of glial fibrillary acidic protein (GFAP), a marker for reactive astrocytes, within 70 μm from the electrode-tissue interface (p < 0.05). Additionally, the coating reduced the microglia activation as shown in decreased Iba-1 and lectin staining, and improved blood-brain barrier integrity indicated by reduced immunoglobulin (IgG) leakage into the tissue around the probes. These findings demonstrate that anti-fouling zwitterionic coating is effective in suppressing the acute inflammatory brain tissue response to implants, and should be further investigated for its potential to improve chronic performance of neural implants.
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Affiliation(s)
- Asiyeh Golabchi
- Department of Bioengineering, University of Pittsburgh, USA; Center for Neural Basis of Cognition, USA
| | - Bingchen Wu
- Department of Bioengineering, University of Pittsburgh, USA; Center for Neural Basis of Cognition, USA
| | - Bin Cao
- Department of Bioengineering, University of Pittsburgh, USA; Center for Neural Basis of Cognition, USA
| | - Christopher J Bettinger
- Department of Biomedical Engineering, Department of Material Science and Engineering, Carnegie Mellon University, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, USA; Center for Neural Basis of Cognition, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, USA.
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32
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Joo HR, Fan JL, Chen S, Pebbles JA, Liang H, Chung JE, Yorita AM, Tooker AC, Tolosa VM, Geaghan-Breiner C, Roumis DK, Liu DF, Haque R, Frank LM. A microfabricated, 3D-sharpened silicon shuttle for insertion of flexible electrode arrays through dura mater into brain. J Neural Eng 2019; 16:066021. [PMID: 31216526 PMCID: PMC7036288 DOI: 10.1088/1741-2552/ab2b2e] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Electrode arrays for chronic implantation in the brain are a critical technology in both neuroscience and medicine. Recently, flexible, thin-film polymer electrode arrays have shown promise in facilitating stable, single-unit recordings spanning months in rats. While array flexibility enhances integration with neural tissue, it also requires removal of the dura mater, the tough membrane surrounding the brain, and temporary bracing to penetrate the brain parenchyma. Durotomy increases brain swelling, vascular damage, and surgical time. Insertion using a bracing shuttle results in additional vascular damage and brain compression, which increase with device diameter; while a higher-diameter shuttle will have a higher critical load and more likely penetrate dura, it will damage more brain parenchyma and vasculature. One way to penetrate the intact dura and limit tissue compression without increasing shuttle diameter is to reduce the force required for insertion by sharpening the shuttle tip. APPROACH We describe a novel design and fabrication process to create silicon insertion shuttles that are sharp in three dimensions and can penetrate rat dura, for faster, easier, and less damaging implantation of polymer arrays. Sharpened profiles are obtained by reflowing patterned photoresist, then transferring its sloped profile to silicon with dry etches. MAIN RESULTS We demonstrate that sharpened shuttles can reliably implant polymer probes through dura to yield high quality single unit and local field potential recordings for at least 95 days. On insertion directly through dura, tissue compression is minimal. SIGNIFICANCE This is the first demonstration of a rat dural-penetrating array for chronic recording. This device obviates the need for a durotomy, reducing surgical time and risk of damage to the blood-brain barrier. This is an improvement to state-of-the-art flexible polymer electrode arrays that facilitates their implantation, particularly in multi-site recording experiments. This sharpening process can also be integrated into silicon electrode array fabrication.
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Affiliation(s)
- Hannah R Joo
- Medical Scientist Training Program and Neuroscience Graduate Program, University of California, San Francisco, CA 94158, United States of America. Kavli Institute for Fundamental Neuroscience, Center for Integrative Neuroscience, and Department of Physiology, University of California, San Francisco, CA 94158, United States of America
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33
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Ramadi KB, Cima MJ. Materials and Devices for Micro-invasive Neural Interfacing. ACTA ACUST UNITED AC 2019. [DOI: 10.1557/adv.2019.424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Arafat MA, Rubin LN, Jefferys JGR, Irazoqui PP. A Method of Flexible Micro-Wire Electrode Insertion in Rodent for Chronic Neural Recording and a Device for Electrode Insertion. IEEE Trans Neural Syst Rehabil Eng 2019; 27:1724-1731. [DOI: 10.1109/tnsre.2019.2932032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Tadayon MA, Chaitanya S, Martyniuk KM, McGowan JC, Roberts SP, Denny CA, Lipson M. 3D microphotonic probe for high resolution deep tissue imaging. OPTICS EXPRESS 2019; 27:22352-22362. [PMID: 31510530 DOI: 10.1364/oe.27.022352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Ultra-compact miniaturized optical components for microendoscopic tools and miniaturized microscopes are required for minimally invasive imaging. Current microendoscopic technologies used for deep tissue imaging procedures are limited to a large diameter and/or low resolution due to manufacturing restrictions. We demonstrate a platform for miniaturization of an optical imaging system for microendoscopic applications with a resolution of 1 µm. We designed our probe using cascaded micro-lenses and waveguides (lensguide) to achieve a probe as small as 100 µm x 100 µm with a field of view of 60 µm in diameter. We demonstrate wide-field microscopy based on our polymeric probe fabricated using photolithography and a two-photon polymerization process.
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Control of neural probe shank flexibility by fluidic pressure in embedded microchannel using PDMS/PI hybrid substrate. PLoS One 2019; 14:e0220258. [PMID: 31339963 PMCID: PMC6655783 DOI: 10.1371/journal.pone.0220258] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/11/2019] [Indexed: 11/19/2022] Open
Abstract
Implantable neural probes are widely used to record and stimulate neural activities. These probes should be stiff enough for insertion. However, it should also be flexible to minimize tissue damage after insertion. Therefore, having dynamic control of the neural probe shank flexibility will be useful. For the first time, we have successfully fabricated flexible neural probes with embedded microfluidic channels for dynamic control of neural probe stiffness by controlling fluidic pressure in the channels. The present hybrid neural probes consisted of polydimethylsiloxane (PDMS) and polyimide (PI) layers could provide the required stiffness for insertion and flexibility during operation. The PDMS channels were fabricated by reversal imprint using a silicon mold and bonded to a PI layer to form the embedded channels in the neural probe. The probe shape was patterned using an oxygen plasma generated by an inductively coupled plasma etching system. The critical buckling force of PDMS/PI neural probes could be tuned from 0.25-1.25 mN depending on the applied fluidic pressure in the microchannels and these probes were successfully inserted into a 0.6% agarose gel that mimicked the stiffness of the brain tissue. Polymer-based neural probes are typically more flexible than conventional metal wire-based probes, and they could potentially provide less tissue damage after implantation.
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37
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Tanaka Y, Nomoto T, Shiki T, Sakata Y, Shimada Y, Hayashida Y, Yagi T. Focal activation of neuronal circuits induced by microstimulation in the visual cortex. J Neural Eng 2019; 16:036007. [PMID: 30818288 DOI: 10.1088/1741-2552/ab0b80] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Microstimulation to the cortical tissue applied with penetrating electrodes delivers current that spreads concentrically around the electrode tip and is known to evoke focal visual sensations, i.e. phosphenes. However, to date, there is no direct evidence depicting the spatiotemporal properties of neuronal activity induced immediately after microstimulation and how such activity drives the subsequent local cortical circuits. APPROACH In the present study, we imaged the spatiotemporal distribution of action potentials (APs) directly induced by microstimulation and the subsequent trans-synaptic signal propagation using a voltage-sensitive dye (VSD) and a calcium-sensitive dye (CaSD) in slice preparations of the mouse primary visual cortex. MAIN RESULTS The directly induced APs were confined to the close vicinity of the electrode tip, and the effective distance of excitation was proportional to the square root of the current intensity. The excitation around the electrode tip in layer IV mainly propagated to layer II/III to further induce the subsequent focal activation in downstream local cortical circuits. The extent of activation in the downstream circuits was restrained by competitive interactions between excitatory and inhibitory signals. Namely, the spread of the excitation to lateral neighbor neurons along the layer II/III was confined by the delayed inhibition that also spread laterally at a faster rate. SIGNIFICANCE These observations indicate that dynamic interactions between excitatory and inhibitory signals play a critical role in the focal activation of a cortical circuit in response to intracortical microstimulation and, therefore, in evoking a localized phosphene.
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Affiliation(s)
- Yuta Tanaka
- Division of Electrical, Electronic, and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
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Kil D, Bovet Carmona M, Ceyssens F, Deprez M, Brancato L, Nuttin B, Balschun D, Puers R. Dextran as a Resorbable Coating Material for Flexible Neural Probes. MICROMACHINES 2019; 10:mi10010061. [PMID: 30658409 PMCID: PMC6356287 DOI: 10.3390/mi10010061] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/27/2018] [Accepted: 01/15/2019] [Indexed: 12/13/2022]
Abstract
In the quest for chronically reliable and bio-tolerable brain interfaces there has been a steady evolution towards the use of highly flexible, polymer-based electrode arrays. The reduced mechanical mismatch between implant and brain tissue has shown to reduce the evoked immune response, which in turn has a positive effect on signal stability and noise. Unfortunately, the low stiffness of the implants also has practical repercussions, making surgical insertion extremely difficult. In this work we explore the use of dextran as a coating material that temporarily stiffens the implant, preventing buckling during insertion. The mechanical properties of dextran coated neural probes are characterized, as well as the different parameters which influence the dissolution rate. Tuning parameters, such as coating thickness and molecular weight of the used dextran, allows customization of the stiffness and dissolution time to precisely match the user's needs. Finally, the immunological response to the coated electrodes was analyzed by performing a histological examination after four months of in vivo testing. The results indicated that a very limited amount of glial scar tissue was formed. Neurons have also infiltrated the area that was initially occupied by the dissolving dextran coating. There was no noticeable drop in neuron density around the site of implantation, confirming the suitability of the coating as a temporary aid during implantation of highly flexible polymer-based neural probes.
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Affiliation(s)
- Dries Kil
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium.
| | - Marta Bovet Carmona
- Laboratory for Biological Psychology, Brain & Cognition, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium.
| | - Frederik Ceyssens
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium.
| | - Marjolijn Deprez
- Experimental Neurosurgery and Neuroanatomy, UZ Herestraat 49 box 7003, 3000 Leuven, Belgium.
| | - Luigi Brancato
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium.
| | - Bart Nuttin
- Experimental Neurosurgery and Neuroanatomy, UZ Herestraat 49 box 7003, 3000 Leuven, Belgium.
| | - Detlef Balschun
- Laboratory for Biological Psychology, Brain & Cognition, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium.
| | - Robert Puers
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium.
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Slow insertion of silicon probes improves the quality of acute neuronal recordings. Sci Rep 2019; 9:111. [PMID: 30643182 PMCID: PMC6331571 DOI: 10.1038/s41598-018-36816-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 11/10/2018] [Indexed: 01/02/2023] Open
Abstract
Neural probes designed for extracellular recording of brain electrical activity are traditionally implanted with an insertion speed between 1 µm/s and 1 mm/s into the brain tissue. Although the physical effects of insertion speed on the tissue are well studied, there is a lack of research investigating how the quality of the acquired electrophysiological signal depends on the speed of probe insertion. In this study, we used four different insertion speeds (0.002 mm/s, 0.02 mm/s, 0.1 mm/s, 1 mm/s) to implant high-density silicon probes into deep layers of the somatosensory cortex of ketamine/xylazine anesthetized rats. After implantation, various qualitative and quantitative properties of the recorded cortical activity were compared across different speeds in an acute manner. Our results demonstrate that after the slowest insertion both the signal-to-noise ratio and the number of separable single units were significantly higher compared with those measured after inserting probes at faster speeds. Furthermore, the amplitude of recorded spikes as well as the quality of single unit clusters showed similar speed-dependent differences. Post hoc quantification of the neuronal density around the probe track showed a significantly higher number of NeuN-labelled cells after the slowest insertion compared with the fastest insertion. Our findings suggest that advancing rigid probes slowly (~1 µm/s) into the brain tissue might result in less tissue damage, and thus in neuronal recordings of improved quality compared with measurements obtained after inserting probes with higher speeds.
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Seo KJ, Artoni P, Qiang Y, Zhong Y, Han X, Shi Z, Yao W, Fagiolini M, Fang H. Transparent, Flexible, Penetrating Microelectrode Arrays with Capabilities of Single-Unit Electrophysiology. ACTA ACUST UNITED AC 2019; 3:e1800276. [PMID: 32627399 DOI: 10.1002/adbi.201800276] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 12/08/2018] [Indexed: 01/08/2023]
Abstract
Accurately mapping neuronal activity across brain networks is critical to understand behaviors, yet it is very challenging due to the need of tools with both high spatial and temporal resolutions. Here, penetrating arrays of flexible microelectrodes made of low-impedance nanomeshes are presented, which are capable of recording single-unit electrophysiological neuronal activity and at the same time, transparent, allowing to bridge electrical and optical brain mapping modalities. These 32 transparent penetrating electrodes with site area, 225 µm2 , have a low impedance of ≈149 kΩ at 1 kHz, an adequate charge injection limit of ≈0.76 mC cm-2 , and up to 100% yield. Mechanical bending tests reveal that the array is robust up to 1000 bending cycles, and its high transmittance of 67% at 550 nm makes it suitable for combining with various optical methods. A temporary stiffening using polyethylene glycol allows the penetrating nanomesh arrays to be inserted into the brain minimally invasively, with in vivo validation of recordings of spontaneous and evoked single-unit activity of neurons across layers of the mouse visual cortex. Together, these results establish a novel neurotechnology-transparent, flexible, penetrating microelectrode arrays-which possesses great potential for brain research.
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Affiliation(s)
- Kyung Jin Seo
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Pietro Artoni
- Center for Life Science, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Yi Qiang
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Yiding Zhong
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Xun Han
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Zhan Shi
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Wenhao Yao
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Michela Fagiolini
- Center for Life Science, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Hui Fang
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA.,Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA.,Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA
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41
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MacManus DB, Murphy JG, Gilchrist MD. Mechanical characterisation of brain tissue up to 35% strain at 1, 10, and 100/s using a custom-built micro-indentation apparatus. J Mech Behav Biomed Mater 2018; 87:256-266. [DOI: 10.1016/j.jmbbm.2018.07.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 07/10/2018] [Accepted: 07/17/2018] [Indexed: 10/28/2022]
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Goncalves SB, Palha JM, Fernandes HC, Souto MR, Pimenta S, Dong T, Yang Z, Ribeiro JF, Correia JH. LED Optrode with Integrated Temperature Sensing for Optogenetics. MICROMACHINES 2018; 9:E473. [PMID: 30424406 PMCID: PMC6187356 DOI: 10.3390/mi9090473] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/18/2018] [Accepted: 09/04/2018] [Indexed: 12/02/2022]
Abstract
In optogenetic studies, the brain is exposed to high-power light sources and inadequate power density or exposure time can cause cell damage from overheating (typically temperature increasing of 2 ∘ C). In order to overcome overheating issues in optogenetics, this paper presents a neural tool capable of assessing tissue temperature over time, combined with the capability of electrical recording and optical stimulation. A silicon-based 8 mm long probe was manufactured to reach deep neural structures. The final proof-of-concept device comprises a double-sided function: on one side, an optrode with LED-based stimulation and platinum (Pt) recording points; and, on the opposite side, a Pt-based thin-film thermoresistance (RTD) for temperature assessing in the photostimulation site surroundings. Pt thin-films for tissue interface were chosen due to its biocompatibility and thermal linearity. A single-shaft probe is demonstrated for integration in a 3D probe array. A 3D probe array will reduce the distance between the thermal sensor and the heating source. Results show good recording and optical features, with average impedance magnitude of 371 k Ω , at 1 kHz, and optical power of 1.2 mW·mm - 2 (at 470 nm), respectively. The manufactured RTD showed resolution of 0.2 ∘ C at 37 ∘ C (normal body temperature). Overall, the results show a device capable of meeting the requirements of a neural interface for recording/stimulating of neural activity and monitoring temperature profile of the photostimulation site surroundings, which suggests a promising tool for neuroscience research filed.
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Affiliation(s)
- S Beatriz Goncalves
- Institute of Applied Micro-Nano Science and Technology-IAMNST, Chongqing Key Laboratory of Colleges and Universities on Micro-Nano Systems Technology and Smart Transducing, Chongqing Engineering Laboratory for Detection, Control and Integrated System, National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Nan'an District, Chongqing 400067, China.
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimaraes 4800-058, Portugal.
| | - José M Palha
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimaraes 4800-058, Portugal.
| | - Helena C Fernandes
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimaraes 4800-058, Portugal.
| | - Márcio R Souto
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimaraes 4800-058, Portugal.
| | - Sara Pimenta
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimaraes 4800-058, Portugal.
| | - Tao Dong
- Institute of Applied Micro-Nano Science and Technology-IAMNST, Chongqing Key Laboratory of Colleges and Universities on Micro-Nano Systems Technology and Smart Transducing, Chongqing Engineering Laboratory for Detection, Control and Integrated System, National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Nan'an District, Chongqing 400067, China.
- Institute for Microsystems-IMS, Faculty of Technology, Natural Sciences and Maritime Sciences, University of South-Eastern Norway (USN), Postboks 235, 3603 Kongsberg, Norway.
| | - Zhaochu Yang
- Institute of Applied Micro-Nano Science and Technology-IAMNST, Chongqing Key Laboratory of Colleges and Universities on Micro-Nano Systems Technology and Smart Transducing, Chongqing Engineering Laboratory for Detection, Control and Integrated System, National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Nan'an District, Chongqing 400067, China.
| | - João F Ribeiro
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimaraes 4800-058, Portugal.
| | - José H Correia
- Institute of Applied Micro-Nano Science and Technology-IAMNST, Chongqing Key Laboratory of Colleges and Universities on Micro-Nano Systems Technology and Smart Transducing, Chongqing Engineering Laboratory for Detection, Control and Integrated System, National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Nan'an District, Chongqing 400067, China.
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimaraes 4800-058, Portugal.
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Tadayon MA, Pavlova I, Martyniuk KM, Mohanty A, Roberts SP, Barbosa F, Denny CA, Lipson M. Microphotonic needle for minimally invasive endoscopic imaging with sub-cellular resolution. Sci Rep 2018; 8:10756. [PMID: 30018316 PMCID: PMC6050293 DOI: 10.1038/s41598-018-29090-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 06/20/2018] [Indexed: 12/21/2022] Open
Abstract
Ultra-compact micro-optical elements for endoscopic instruments and miniaturized microscopes allow for non-invasive and non-destructive examination of microstructures and tissues. With sub-cellular level resolution such instruments could provide immediate diagnosis that is virtually consistent with a histologic diagnosis enabling for example to differentiate the boundaries between malignant and benign tissue. Such instruments are now being developed at a rapid rate; however, current manufacturing technologies limit the instruments to very large sizes, well beyond the sub-mm sizes required in order to ensure minimal tissue damage. We show here a platform based on planar microfabrication and soft lithography that overcomes the limitation of current optical elements enabling single cell resolution. We show the ability to resolve lithographic features that are as small as 2 μm using probes with a cross section that is only 100 microns in size. We also show the ability to image individual activated neural cells in brain slices via our fabricated probe.
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Affiliation(s)
| | - Ina Pavlova
- Department of Psychiatry, Columbia University, New York, NY, USA
| | | | - Aseema Mohanty
- Department of Electrical Engineering, Columbia University, New York, NY, USA
| | | | - Felippe Barbosa
- Department of Physics, University of Campinas, Campinas, SP, Brazil
| | | | - Michal Lipson
- Department of Electrical Engineering, Columbia University, New York, NY, USA.
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44
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Focal, remote-controlled, chronic chemical modulation of brain microstructures. Proc Natl Acad Sci U S A 2018; 115:7254-7259. [PMID: 29941557 DOI: 10.1073/pnas.1804372115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Direct delivery of fluid to brain parenchyma is critical in both research and clinical settings. This is usually accomplished through acutely inserted cannulas. This technique, however, results in backflow and significant dispersion away from the infusion site, offering little spatial or temporal control in delivering fluid. We present an implantable, MRI-compatible, remotely controlled drug delivery system for minimally invasive interfacing with brain microstructures in freely moving animals. We show that infusions through acutely inserted needles target a region more than twofold larger than that of identical infusions through chronically implanted probes due to reflux and backflow. We characterize the dynamics of in vivo infusions using positron emission tomography techniques. Volumes as small as 167 nL of copper-64 and fludeoxyglucose labeled agents are quantified. We further demonstrate the importance of precise drug volume dosing to neural structures to elicit behavioral effects reliably. Selective modulation of the substantia nigra, a critical node in basal ganglia circuitry, via muscimol infusion induces behavioral changes in a volume-dependent manner, even when the total dose remains constant. Chronic device viability is confirmed up to 1-y implantation in rats. This technology could potentially enable precise investigation of neurological disease pathology in preclinical models, and more efficacious treatment in human patients.
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Michelson NJ, Vazquez AL, Eles JR, Salatino JW, Purcell EK, Williams JJ, Cui XT, Kozai TDY. Multi-scale, multi-modal analysis uncovers complex relationship at the brain tissue-implant neural interface: new emphasis on the biological interface. J Neural Eng 2018; 15:033001. [PMID: 29182149 PMCID: PMC5967409 DOI: 10.1088/1741-2552/aa9dae] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Implantable neural electrode devices are important tools for neuroscience research and have an increasing range of clinical applications. However, the intricacies of the biological response after implantation, and their ultimate impact on recording performance, remain challenging to elucidate. Establishing a relationship between the neurobiology and chronic recording performance is confounded by technical challenges related to traditional electrophysiological, material, and histological limitations. This can greatly impact the interpretations of results pertaining to device performance and tissue health surrounding the implant. APPROACH In this work, electrophysiological activity and immunohistological analysis are compared after controlling for motion artifacts, quiescent neuronal activity, and material failure of devices in order to better understand the relationship between histology and electrophysiological outcomes. MAIN RESULTS Even after carefully accounting for these factors, the presence of viable neurons and lack of glial scarring does not convey single unit recording performance. SIGNIFICANCE To better understand the biological factors influencing neural activity, detailed cellular and molecular tissue responses were examined. Decreases in neural activity and blood oxygenation in the tissue surrounding the implant, shift in expression levels of vesicular transporter proteins and ion channels, axon and myelin injury, and interrupted blood flow in nearby capillaries can impact neural activity around implanted neural interfaces. Combined, these tissue changes highlight the need for more comprehensive, basic science research to elucidate the relationship between biology and chronic electrophysiology performance in order to advance neural technologies.
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Affiliation(s)
| | - Alberto L Vazquez
- Department of Bioengineering, University of Pittsburgh
- Department of Radiology, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
- Center for Neuroscience, University of Pittsburgh
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
| | | | - Erin K Purcell
- Department of Biomedical Engineering, Michigan State University
| | | | - X. Tracy Cui
- Department of Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
- McGowan Institute of Regenerative Medicine, University of Pittsburgh
| | - Takashi DY Kozai
- Department of Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
- Center for Neuroscience, University of Pittsburgh
- McGowan Institute of Regenerative Medicine, University of Pittsburgh
- NeuroTech Center, University of Pittsburgh Brain Institute
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Wellman SM, Eles JR, Ludwig KA, Seymour JP, Michelson NJ, McFadden WE, Vazquez AL, Kozai TDY. A Materials Roadmap to Functional Neural Interface Design. ADVANCED FUNCTIONAL MATERIALS 2018; 28:1701269. [PMID: 29805350 PMCID: PMC5963731 DOI: 10.1002/adfm.201701269] [Citation(s) in RCA: 169] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Advancement in neurotechnologies for electrophysiology, neurochemical sensing, neuromodulation, and optogenetics are revolutionizing scientific understanding of the brain while enabling treatments, cures, and preventative measures for a variety of neurological disorders. The grand challenge in neural interface engineering is to seamlessly integrate the interface between neurobiology and engineered technology, to record from and modulate neurons over chronic timescales. However, the biological inflammatory response to implants, neural degeneration, and long-term material stability diminish the quality of interface overtime. Recent advances in functional materials have been aimed at engineering solutions for chronic neural interfaces. Yet, the development and deployment of neural interfaces designed from novel materials have introduced new challenges that have largely avoided being addressed. Many engineering efforts that solely focus on optimizing individual probe design parameters, such as softness or flexibility, downplay critical multi-dimensional interactions between different physical properties of the device that contribute to overall performance and biocompatibility. Moreover, the use of these new materials present substantial new difficulties that must be addressed before regulatory approval for use in human patients will be achievable. In this review, the interdependence of different electrode components are highlighted to demonstrate the current materials-based challenges facing the field of neural interface engineering.
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Affiliation(s)
- Steven M Wellman
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - James R Eles
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Kip A Ludwig
- Department of Neurologic Surgery, 200 First St. SW, Rochester, MN 55905
| | - John P Seymour
- Electrical & Computer Engineering, 1301 Beal Ave., 2227 EECS, Ann Arbor, MI 48109
| | - Nicholas J Michelson
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - William E McFadden
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Alberto L Vazquez
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Takashi D Y Kozai
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
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47
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Zhang G, Zeng X, Su Y, Borras FX, de Rooij MB, Ren T, van der Heide E. Influence of suture size on the frictional performance of surgical suture evaluated by a penetration friction measurement approach. J Mech Behav Biomed Mater 2018; 80:171-179. [PMID: 29427933 DOI: 10.1016/j.jmbbm.2018.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 01/20/2018] [Accepted: 02/02/2018] [Indexed: 11/29/2022]
Abstract
The frictional performances of surgical sutures have been found to play a vital role in their functionality. The purpose of this paper is to understand the frictional performance of multifilament surgical sutures interacting with skin substitute, by means of a penetration friction apparatus (PFA). The influence of the size of the surgical suture was investigated. The relationship between the friction force and normal force was considered, in order to evaluate the friction performance of a surgical suture penetrating a skin substitute. The friction force was measured by PFA. The normal force applied to the surgical suture was estimated based on a Hertzian contact model, a finite element model (FEM), and a uniaxial deformation model (UDM). The results indicated that the penetration friction force increased as the size of the multifilament surgical suture increased. In addition, when the normal force was predicted by UDM, it was found that the ratio between the friction force and normal force decreased as the normal force increased. A comparison of the results suggested that the UDM was appropriate in predicting the frictional behavior of surgical suturing.
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Affiliation(s)
- Gangqiang Zhang
- Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, 200240, Shanghai, China; University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands
| | - Xiangqiong Zeng
- University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands; Chinese Academy of Sciences, Shanghai Advanced Research Institute, Lubricating Materials Laboratory, 201210 Shanghai, China
| | - Yibo Su
- Brightlands Materials Center, Urmonderbaan 22 6167 RD Geleen, The Netherlands
| | - F X Borras
- University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands
| | - Matthijn B de Rooij
- University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands
| | - Tianhui Ren
- Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, 200240, Shanghai, China.
| | - Emile van der Heide
- University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands; TU Delft, Faculty of Civil Engineering and Geosciences, Stevinweg 1, 2628 CN Delft, The Netherlands; Ghent University, Soete Laboratory, Technologiepark Zwijnaarde 903, B-9052 Zwijnaarde, Belgium
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48
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Turtaev S, Leite IT, Altwegg-Boussac T, Pakan JMP, Rochefort NL, Čižmár T. High-fidelity multimode fibre-based endoscopy for deep brain in vivo imaging. LIGHT, SCIENCE & APPLICATIONS 2018; 7:92. [PMID: 30479758 PMCID: PMC6249210 DOI: 10.1038/s41377-018-0094-x] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 11/01/2018] [Accepted: 11/04/2018] [Indexed: 05/06/2023]
Abstract
Progress in neuroscience relies on new techniques for investigating the complex dynamics of neuronal networks. An ongoing challenge is to achieve minimally invasive and high-resolution observations of neuronal activity in vivo inside deep brain areas. Recently introduced methods for holographic control of light propagation in complex media enable the use of a hair-thin multimode optical fibre as an ultranarrow imaging tool. Compared to endoscopes based on graded-index lenses or fibre bundles, this new approach offers a footprint reduction exceeding an order of magnitude, combined with a significant enhancement in resolution. We designed a compact and high-speed system for fluorescent imaging at the tip of a fibre, achieving a resolution of 1.18 ± 0.04 µm across a 50-µm field of view, yielding 7-kilopixel images at a rate of 3.5 frames/s. Furthermore, we demonstrate in vivo observations of cell bodies and processes of inhibitory neurons within deep layers of the visual cortex and hippocampus of anaesthetised mice. This study paves the way for modern microscopy to be applied deep inside tissues of living animal models while exerting a minimal impact on their structural and functional properties.
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Affiliation(s)
- Sergey Turtaev
- Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, Jena, 07745 Germany
- School of Life Sciences, University of Dundee, Nethergate, Dundee, DD1 4HN UK
| | - Ivo T. Leite
- Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, Jena, 07745 Germany
- School of Science and Engineering, University of Dundee, Nethergate, Dundee, DD1 4HN UK
| | - Tristan Altwegg-Boussac
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building 15, George Square, Edinburgh, EH8 9XD UK
| | - Janelle M. P. Pakan
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building 15, George Square, Edinburgh, EH8 9XD UK
- Center for Behavioral Brain Sciences, Institute of Cognitive Neurology and Dementia Research, German Center for Neurodegenerative Diseases, Leipziger Straße 44, Haus 64, Magdeburg, 39120 Germany
| | - Nathalie L. Rochefort
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building 15, George Square, Edinburgh, EH8 9XD UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Tomáš Čižmár
- Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, Jena, 07745 Germany
- School of Science and Engineering, University of Dundee, Nethergate, Dundee, DD1 4HN UK
- Institute of Scientific Instruments of CAS, Kralovopolska 147, Brno, 612 64 Czech Republic
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Brain Tissue Responses to Guide Cannula Insertion and Replacement of a Microrecording Electrode with a Definitive DBS Electrode. J Med Biol Eng 2017. [DOI: 10.1007/s40846-017-0328-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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50
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Anand S, Kumar SS, Muthuswamy J. Autonomous control for mechanically stable navigation of microscale implants in brain tissue to record neural activity. Biomed Microdevices 2017; 18:72. [PMID: 27457752 DOI: 10.1007/s10544-016-0093-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Emerging neural prosthetics require precise positional tuning and stable interfaces with single neurons for optimal function over a lifetime. In this study, we report an autonomous control to precisely navigate microscale electrodes in soft, viscoelastic brain tissue without visual feedback. The autonomous control optimizes signal-to-noise ratio (SNR) of single neuronal recordings in viscoelastic brain tissue while maintaining quasi-static mechanical stress conditions to improve stability of the implant-tissue interface. Force-displacement curves from microelectrodes in in vivo rodent experiments are used to estimate viscoelastic parameters of the brain. Using a combination of computational models and experiments, we determined an optimal movement for the microelectrodes with bidirectional displacements of 3:2 ratio between forward and backward displacements and a inter-movement interval of 40 s for minimizing mechanical stress in the surrounding brain tissue. A regulator with the above optimal bidirectional motion for the microelectrodes in in vivo experiments resulted in significant reduction in the number of microelectrode movements (0.23 movements/min) and longer periods of stable SNR (53 % of the time) compared to a regulator using a conventional linear, unidirectional microelectrode movement (with 1.48 movements/min and stable SNR 23 % of the time).
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Affiliation(s)
- Sindhu Anand
- Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, ECG 334, P. O. Box 879709, Tempe, AZ, 85287-9709, USA
| | - Swathy Sampath Kumar
- Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, ECG 334, P. O. Box 879709, Tempe, AZ, 85287-9709, USA
| | - Jit Muthuswamy
- Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, ECG 334, P. O. Box 879709, Tempe, AZ, 85287-9709, USA.
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