1
|
Dawit H, Zhao Y, Wang J, Pei R. Advances in conductive hydrogels for neural recording and stimulation. Biomater Sci 2024; 12:2786-2800. [PMID: 38682423 DOI: 10.1039/d4bm00048j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
The brain-computer interface (BCI) allows the human or animal brain to directly interact with the external environment through the neural interfaces, thus playing the role of monitoring, protecting, improving/restoring, enhancing, and replacing. Recording electrophysiological information such as brain neural signals is of great importance in health monitoring and disease diagnosis. According to the electrode position, it can be divided into non-implantable, semi-implantable, and implantable. Among them, implantable neural electrodes can obtain the highest-quality electrophysiological information, so they have the most promising application. However, due to the chemo-mechanical mismatch between devices and tissues, the adverse foreign body response and performance loss over time seriously restrict the development and application of implantable neural electrodes. Given the challenges, conductive hydrogel-based neural electrodes have recently attracted much attention, owing to many advantages such as good mechanical match with the native tissues, negligible foreign body response, and minimal signal attenuation. This review mainly focuses on the current development of conductive hydrogels as a biocompatible framework for neural tissue and conductivity-supporting substrates for the transmission of electrical signals of neural tissue to speed up electrical regeneration and their applications in neural sensing and recording as well as stimulation.
Collapse
Affiliation(s)
- Hewan Dawit
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, PR China
- CAS Key Laboratory of Nano-Bio Interface, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China.
| | - Yuewu Zhao
- CAS Key Laboratory of Nano-Bio Interface, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China.
| | - Jine Wang
- College of Medicine and Nursing, Shandong Provincial Engineering Laboratory of Novel Pharmaceutical Excipients, Sustained and Controlled Release Preparations, Dezhou University, China.
- Jiangxi Institute of Nanotechnology, Nanchang, 330200, China
| | - Renjun Pei
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, PR China
- CAS Key Laboratory of Nano-Bio Interface, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China.
| |
Collapse
|
2
|
Wu B, Castagnola E, McClung CA, Cui XT. PEDOT/CNT Flexible MEAs Reveal New Insights into the Clock Gene's Role in Dopamine Dynamics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2308212. [PMID: 38430532 DOI: 10.1002/advs.202308212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/26/2024] [Indexed: 03/04/2024]
Abstract
Substantial evidence has shown that the Circadian Locomotor Output Cycles Kaput (Clock) gene is a core transcription factor of circadian rhythms that regulates dopamine (DA) synthesis. To shed light on the mechanism of this interaction, flexible multielectrode arrays (MEAs) are developed that can measure both DA concentrations and electrophysiology chronically. The dual functionality is enabled by conducting polymer PEDOT doped with acid-functionalized carbon nanotubes (CNT). The PEDOT/CNT microelectrode coating maintained stable electrochemical impedance and DA detection by square wave voltammetry for 4 weeks in vitro. When implanted in wild-type (WT) and Clock mutation (MU) mice, MEAs measured tonic DA concentration and extracellular neural activity with high spatial and temporal resolution for 4 weeks. A diurnal change of DA concentration in WT is observed, but not in MU, and a higher basal DA concentration and stronger cocaine-induced DA increase in MU. Meanwhile, striatal neuronal firing rate is found to be positively correlated with DA concentration in both animal groups. These findings offer new insights into DA dynamics in the context of circadian rhythm regulation, and the chronically reliable performance and dual measurement capability of this technology hold great potential for a broad range of neuroscience research.
Collapse
Affiliation(s)
- Bingchen Wu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA, 15213, USA
| | - Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA, 71272, USA
| | - Colleen A McClung
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA, 15213, USA
- McGowan Institute for Regenerative Medicine, Pittsburgh, PA, 15219, USA
| |
Collapse
|
3
|
Faul EBA, Broussard AM, Rivera DR, Pwint MY, Wu B, Cao Q, Bailey D, Cui XT, Castagnola E. Batch Fabrication of Microelectrode Arrays with Glassy Carbon Microelectrodes and Interconnections for Neurochemical Sensing: Promises and Challenges. MICROMACHINES 2024; 15:277. [PMID: 38399004 PMCID: PMC10892456 DOI: 10.3390/mi15020277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/07/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024]
Abstract
Flexible multielectrode arrays with glassy carbon (GC) electrodes and metal interconnection (hybrid MEAs) have shown promising performance in multi-channel neurochemical sensing. A primary challenge faced by hybrid MEAs fabrication is the adhesion of the metal traces with the GC electrodes, as prolonged electrical and mechanical stimulation can lead to adhesion failure. Previous devices with GC electrodes and interconnects made of a homogeneous material (all GC) demonstrated exceptional electrochemical stability but required miniaturization for enhanced tissue integration and chronic electrochemical sensing. In this study, we used two different methods for the fabrication of all GC-MEAs on thin flexible substrates with miniaturized features. The first method, like that previously reported, involves a double pattern-transfer photolithographic process, including transfer-bonding on temporary polymeric support. The second method requires a double-etching process, which uses a 2 µm-thick low stress silicon nitride coating of the Si wafer as the bottom insulator layer for the MEAs, bypassing the pattern-transfer and demonstrating a novel technique with potential advantages. We confirmed the feasibility of the two fabrication processes by verifying the practical conductivity of 3 µm-wide 2 µm-thick GC traces, the GC microelectrode functionality, and their sensing capability for the detection of serotonin using fast scan cyclic voltammetry. Through the exchange and discussion of insights regarding the strengths and limitations of these microfabrication methods, our goal is to propel the advancement of GC-based MEAs for the next generation of neural interface devices.
Collapse
Affiliation(s)
- Emma-Bernadette A. Faul
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
| | - Austin M. Broussard
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
| | - Daniel R. Rivera
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
| | - May Yoon Pwint
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Bingchen Wu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Qun Cao
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
| | - Davis Bailey
- Institute for Micromanufacturing, Louisiana Tech University, Ruston, LA 15213, USA;
| | - X. Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219-3110, USA
| | - Elisa Castagnola
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
| |
Collapse
|
4
|
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.
Collapse
Affiliation(s)
- Lucas S. Kumosa
- Neuronano Research CenterDepartment of Experimental Medical ScienceMedical FacultyLund UniversityMedicon Village, Byggnad 404 A2, Scheelevägen 8Lund223 81Sweden
| |
Collapse
|
5
|
Wang Y, Yang X, Zhang X, Wang Y, Pei W. Implantable intracortical microelectrodes: reviewing the present with a focus on the future. MICROSYSTEMS & NANOENGINEERING 2023; 9:7. [PMID: 36620394 PMCID: PMC9814492 DOI: 10.1038/s41378-022-00451-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 08/08/2022] [Accepted: 08/22/2022] [Indexed: 06/17/2023]
Abstract
Implantable intracortical microelectrodes can record a neuron's rapidly changing action potentials (spikes). In vivo neural activity recording methods often have either high temporal or spatial resolution, but not both. There is an increasing need to record more neurons over a longer duration in vivo. However, there remain many challenges to overcome before achieving long-term, stable, high-quality recordings and realizing comprehensive, accurate brain activity analysis. Based on the vision of an idealized implantable microelectrode device, the performance requirements for microelectrodes are divided into four aspects, including recording quality, recording stability, recording throughput, and multifunctionality, which are presented in order of importance. The challenges and current possible solutions for implantable microelectrodes are given from the perspective of each aspect. The current developments in microelectrode technology are analyzed and summarized.
Collapse
Affiliation(s)
- Yang Wang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xinze Yang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xiwen Zhang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yijun Wang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
- Chinese Institute for Brain Research, 102206 Beijing, China
| | - Weihua Pei
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| |
Collapse
|
6
|
Erofeev A, Antifeev I, Bolshakova A, Bezprozvanny I, Vlasova O. In Vivo Penetrating Microelectrodes for Brain Electrophysiology. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22239085. [PMID: 36501805 PMCID: PMC9735502 DOI: 10.3390/s22239085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/14/2022] [Accepted: 11/22/2022] [Indexed: 05/13/2023]
Abstract
In recent decades, microelectrodes have been widely used in neuroscience to understand the mechanisms behind brain functions, as well as the relationship between neural activity and behavior, perception and cognition. However, the recording of neuronal activity over a long period of time is limited for various reasons. In this review, we briefly consider the types of penetrating chronic microelectrodes, as well as the conductive and insulating materials for microelectrode manufacturing. Additionally, we consider the effects of penetrating microelectrode implantation on brain tissue. In conclusion, we review recent advances in the field of in vivo microelectrodes.
Collapse
Affiliation(s)
- Alexander Erofeev
- Laboratory of Molecular Neurodegeneration, Graduate School of Biomedical Systems and Technologies, Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
- Correspondence: (A.E.); (O.V.)
| | - Ivan Antifeev
- Laboratory of Methods and Instruments for Genetic and Immunoassay Analysis, Institute for Analytical Instrumentation of the Russian Academy of Sciences, 198095 Saint Petersburg, Russia
| | - Anastasia Bolshakova
- Laboratory of Molecular Neurodegeneration, Graduate School of Biomedical Systems and Technologies, Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Graduate School of Biomedical Systems and Technologies, Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Olga Vlasova
- Laboratory of Molecular Neurodegeneration, Graduate School of Biomedical Systems and Technologies, Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
- Correspondence: (A.E.); (O.V.)
| |
Collapse
|
7
|
Castagnola E, Robbins EM, Wu B, Pwint MY, Garg R, Cohen-Karni T, Cui XT. Flexible Glassy Carbon Multielectrode Array for In Vivo Multisite Detection of Tonic and Phasic Dopamine Concentrations. BIOSENSORS 2022; 12:540. [PMID: 35884343 PMCID: PMC9312827 DOI: 10.3390/bios12070540] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 07/13/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Dopamine (DA) plays a central role in the modulation of various physiological brain functions, including learning, motivation, reward, and movement control. The DA dynamic occurs over multiple timescales, including fast phasic release, as a result of neuronal firing and slow tonic release, which regulates the phasic firing. Real-time measurements of tonic and phasic DA concentrations in the living brain can shed light on the mechanism of DA dynamics underlying behavioral and psychiatric disorders and on the action of pharmacological treatments targeting DA. Current state-of-the-art in vivo DA detection technologies are limited in either spatial or temporal resolution, channel count, longitudinal stability, and ability to measure both phasic and tonic dynamics. We present here an implantable glassy carbon (GC) multielectrode array on a SU-8 flexible substrate for integrated multichannel phasic and tonic measurements of DA concentrations. The GC MEA demonstrated in vivo multichannel fast-scan cyclic voltammetry (FSCV) detection of electrically stimulated phasic DA release simultaneously at different locations of the mouse dorsal striatum. Tonic DA measurement was enabled by coating GC electrodes with poly(3,4-ethylenedioxythiophene)/carbon nanotube (PEDOT/CNT) and using optimized square-wave voltammetry (SWV). Implanted PEDOT/CNT-coated MEAs achieved stable detection of tonic DA concentrations for up to 3 weeks in the mouse dorsal striatum. This is the first demonstration of implantable flexible MEA capable of multisite electrochemical sensing of both tonic and phasic DA dynamics in vivo with chronic stability.
Collapse
Affiliation(s)
- Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
| | - Elaine M. Robbins
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
| | - Bingchen Wu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - May Yoon Pwint
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Raghav Garg
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (R.G.); (T.C.-K.)
| | - Tzahi Cohen-Karni
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (R.G.); (T.C.-K.)
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
| |
Collapse
|
8
|
Moslehi S, Rowland C, Smith JH, Watterson WJ, Miller D, Niell CM, Alemán BJ, Perez MT, Taylor RP. Controlled assembly of retinal cells on fractal and Euclidean electrodes. PLoS One 2022; 17:e0265685. [PMID: 35385490 PMCID: PMC8985931 DOI: 10.1371/journal.pone.0265685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/04/2022] [Indexed: 11/25/2022] Open
Abstract
Controlled assembly of retinal cells on artificial surfaces is important for fundamental cell research and medical applications. We investigate fractal electrodes with branches of vertically-aligned carbon nanotubes and silicon dioxide gaps between the branches that form repeating patterns spanning from micro- to milli-meters, along with single-scaled Euclidean electrodes. Fluorescence and electron microscopy show neurons adhere in large numbers to branches while glial cells cover the gaps. This ensures neurons will be close to the electrodes’ stimulating electric fields in applications. Furthermore, glia won’t hinder neuron-branch interactions but will be sufficiently close for neurons to benefit from the glia’s life-supporting functions. This cell ‘herding’ is adjusted using the fractal electrode’s dimension and number of repeating levels. We explain how this tuning facilitates substantial glial coverage in the gaps which fuels neural networks with small-world structural characteristics. The large branch-gap interface then allows these networks to connect to the neuron-rich branches.
Collapse
Affiliation(s)
- Saba Moslehi
- Physics Department, University of Oregon, Eugene, Oregon, United States of America
- Materials Science Institute, University of Oregon, Eugene, Oregon, United States of America
| | - Conor Rowland
- Physics Department, University of Oregon, Eugene, Oregon, United States of America
- Materials Science Institute, University of Oregon, Eugene, Oregon, United States of America
| | - Julian H. Smith
- Physics Department, University of Oregon, Eugene, Oregon, United States of America
- Materials Science Institute, University of Oregon, Eugene, Oregon, United States of America
| | - William J. Watterson
- Physics Department, University of Oregon, Eugene, Oregon, United States of America
- Materials Science Institute, University of Oregon, Eugene, Oregon, United States of America
| | - David Miller
- Physics Department, University of Oregon, Eugene, Oregon, United States of America
- Materials Science Institute, University of Oregon, Eugene, Oregon, United States of America
- Oregon Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon, United States of America
| | - Cristopher M. Niell
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
- Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Benjamín J. Alemán
- Physics Department, University of Oregon, Eugene, Oregon, United States of America
- Materials Science Institute, University of Oregon, Eugene, Oregon, United States of America
- Oregon Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon, United States of America
- Phil and Penny Knight Campus for Accelerating Scientific Impact, University of Oregon, Eugene, Oregon, United States of America
| | - Maria-Thereza Perez
- Division of Ophthalmology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
- NanoLund, Lund University, Lund, Sweden
- * E-mail: (RPT); (MTP)
| | - Richard P. Taylor
- Physics Department, University of Oregon, Eugene, Oregon, United States of America
- Materials Science Institute, University of Oregon, Eugene, Oregon, United States of America
- Phil and Penny Knight Campus for Accelerating Scientific Impact, University of Oregon, Eugene, Oregon, United States of America
- * E-mail: (RPT); (MTP)
| |
Collapse
|
9
|
Balakrishnan G, Song J, Mou C, Bettinger CJ. Recent Progress in Materials Chemistry to Advance Flexible Bioelectronics in Medicine. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106787. [PMID: 34751987 PMCID: PMC8917047 DOI: 10.1002/adma.202106787] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/15/2021] [Indexed: 05/09/2023]
Abstract
Designing bioelectronic devices that seamlessly integrate with the human body is a technological pursuit of great importance. Bioelectronic medical devices that reliably and chronically interface with the body can advance neuroscience, health monitoring, diagnostics, and therapeutics. Recent major efforts focus on investigating strategies to fabricate flexible, stretchable, and soft electronic devices, and advances in materials chemistry have emerged as fundamental to the creation of the next generation of bioelectronics. This review summarizes contemporary advances and forthcoming technical challenges related to three principal components of bioelectronic devices: i) substrates and structural materials, ii) barrier and encapsulation materials, and iii) conductive materials. Through notable illustrations from the literature, integration and device fabrication strategies and associated challenges for each material class are highlighted.
Collapse
Affiliation(s)
| | - Jiwoo Song
- Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
| | - Chenchen Mou
- Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
| | | |
Collapse
|
10
|
Kilias A, Lee YT, Froriep UP, Sielaff C, Moser D, Holzhammer T, Egert U, Fang W, Paul O, Ruther P. Intracortical probe arrays with silicon backbone and microelectrodes on thin polyimide wings enable long-term stable recordings in vivo. J Neural Eng 2021; 18. [PMID: 34781276 DOI: 10.1088/1741-2552/ac39b7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 11/15/2021] [Indexed: 11/12/2022]
Abstract
Objective.Recording and stimulating neuronal activity across different brain regions requires interfacing at multiple sites using dedicated tools while tissue reactions at the recording sites often prevent their successful long-term application. This implies the technological challenge of developing complex probe geometries while keeping the overall footprint minimal, and of selecting materials compatible with neural tissue. While the potential of soft materials in reducing tissue response is uncontested, the implantation of these materials is often limited to reliably target neuronal structures across large brain volumes.Approach.We report on the development of a new multi-electrode array exploiting the advantages of soft and stiff materials by combining 7-µm-thin polyimide wings carrying platinum electrodes with a silicon backbone enabling a safe probe implantation. The probe fabrication applies microsystems technologies in combination with a temporal wafer fixation method for rear side processing, i.e. grinding and deep reactive ion etching, of slender probe shanks and electrode wings. The wing-type neural probes are chronically implanted into the entorhinal-hippocampal formation in the mouse forin vivorecordings of freely behaving animals.Main results.Probes comprising the novel wing-type electrodes have been realized and characterized in view of their electrical performance and insertion capability. Chronic electrophysiologicalin vivorecordings of the entorhinal-hippocampal network in the mouse of up to 104 days demonstrated a stable yield of channels containing identifiable multi-unit and single-unit activity outperforming probes with electrodes residing on a Si backbone.Significance.The innovative fabrication process using a process compatible, temporary wafer bonding allowed to realize new Michigan-style probe arrays. The wing-type probe design enables a precise probe insertion into brain tissue and long-term stable recordings of unit activity due to the application of a stable backbone and 7-µm-thin probe wings provoking locally a minimal tissue response and protruding from the glial scare of the backbone.
Collapse
Affiliation(s)
- Antje Kilias
- Biomicrotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Yu-Tao Lee
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Institute of NanoEngineering and Microsystems, National Tsing-Hua University, Hsinchu, Taiwan
| | - Ulrich P Froriep
- Biomicrotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany.,Department of Implant Systems, Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Hannover, Germany
| | - Charlotte Sielaff
- Department of Implant Systems, Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Hannover, Germany
| | - Dominik Moser
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Tobias Holzhammer
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Ulrich Egert
- Biomicrotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany.,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
| | - Weileun Fang
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu City, Taiwan
| | - Oliver Paul
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
| | - Patrick Ruther
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
| |
Collapse
|
11
|
Khan ZM, Wilts E, Vlaisavljevich E, Long TE, Verbridge SS. Electroresponsive Hydrogels for Therapeutic Applications in the Brain. Macromol Biosci 2021; 22:e2100355. [PMID: 34800348 DOI: 10.1002/mabi.202100355] [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: 09/03/2021] [Revised: 10/29/2021] [Indexed: 12/22/2022]
Abstract
Electroresponsive hydrogels possess a conducting material component and respond to electric stimulation through reversible absorption and expulsion of water. The high level of hydration, soft elastomeric compliance, biocompatibility, and enhanced electrochemical properties render these hydrogels suitable for implantation in the brain to enhance the transmission of neural electric signals and ion transport. This review provides an overview of critical electroresponsive hydrogel properties for augmenting electric stimulation in the brain. A background on electric stimulation in the brain through electroresponsive hydrogels is provided. Common conducting materials and general techniques to integrate them into hydrogels are briefly discussed. This review focuses on and summarizes advances in electric stimulation of electroconductive hydrogels for therapeutic applications in the brain, such as for controlling delivery of drugs, directing neural stem cell differentiation and neurogenesis, improving neural biosensor capabilities, and enhancing neural electrode-tissue interfaces. The key challenges in each of these applications are discussed and recommendations for future research are also provided.
Collapse
Affiliation(s)
- Zerin M Khan
- Virginia Tech - Wake Forest University School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Emily Wilts
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Eli Vlaisavljevich
- Virginia Tech - Wake Forest University School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Timothy E Long
- Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Arizona State University, Tempe, AZ, 85287, USA
| | - Scott S Verbridge
- Virginia Tech - Wake Forest University School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| |
Collapse
|
12
|
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.
Collapse
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.
| |
Collapse
|
13
|
Liu X, Bibineyshvili Y, Robles DA, Boreland AJ, Margolis DJ, Shreiber DI, Zahn JD. Fabrication of a Multilayer Implantable Cortical Microelectrode Probe to Improve Recording Potential. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2021; 30:569-581. [PMID: 34539168 PMCID: PMC8445332 DOI: 10.1109/jmems.2021.3092230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Intracortical neural probes are a key enabling technology for acquiring high fidelity neural signals within the cortex. They are viewed as a crucial component of brain-computer interfaces (BCIs) in order to record electrical activities from neurons within the brain. Smaller, more flexible, polymer-based probes have been investigated for their potential to limit the acute and chronic neural tissue response. Conventional methods of patterning electrodes and connecting traces on a single supporting layer can limit the number of recording sites which can be defined, particularly when designing narrower probes. We present a novel strategy of increasing the number of recording sites without proportionally increasing the size of the probe by using a multilayer fabrication process to vertically layer recording traces on multiple Parylene support layers, allowing more recording traces to be defined on a smaller probe width. Using this approach, we are able to define 16 electrodes on 4 supporting layers (4 electrodes per layer), each with a 30 μm diameter recording window and 5 μm wide connecting trace defined by conventional LWUV lithography, on an 80 μm wide by 9 μm thick microprobe. Prior to in vitro and in vivo validation, the multilayer probes are electrically characterized via impedance spectroscopy and evaluating crosstalk between adjacent layers. Demonstration of acute in vitro recordings in a cerebral organoid model and in vivo recordings in a murine model indicate the probe's capability for single unit recordings. This work demonstrates the ability to fabricate smaller, more compliant neural probes without sacrificing electrode density.
Collapse
Affiliation(s)
- Xin Liu
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| | - Yelena Bibineyshvili
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA
| | - Denise A Robles
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| | - Andrew J Boreland
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA
| | - David J Margolis
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA
| | - David I Shreiber
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| | - Jeffrey D Zahn
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Hejazi M, Tong W, Ibbotson MR, Prawer S, Garrett DJ. Advances in Carbon-Based Microfiber Electrodes for Neural Interfacing. Front Neurosci 2021; 15:658703. [PMID: 33912007 PMCID: PMC8072048 DOI: 10.3389/fnins.2021.658703] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
Neural interfacing devices using penetrating microelectrode arrays have emerged as an important tool in both neuroscience research and medical applications. These implantable microelectrode arrays enable communication between man-made devices and the nervous system by detecting and/or evoking neuronal activities. Recent years have seen rapid development of electrodes fabricated using flexible, ultrathin carbon-based microfibers. Compared to electrodes fabricated using rigid materials and larger cross-sections, these microfiber electrodes have been shown to reduce foreign body responses after implantation, with improved signal-to-noise ratio for neural recording and enhanced resolution for neural stimulation. Here, we review recent progress of carbon-based microfiber electrodes in terms of material composition and fabrication technology. The remaining challenges and future directions for development of these arrays will also be discussed. Overall, these microfiber electrodes are expected to improve the longevity and reliability of neural interfacing devices.
Collapse
Affiliation(s)
- Maryam Hejazi
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - Wei Tong
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
| | - Michael R. Ibbotson
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Steven Prawer
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - David J. Garrett
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- School of Engineering, RMIT University, Melbourne, VIC, Australia
| |
Collapse
|
16
|
Vandekerckhove B, Missinne J, Vonck K, Bauwens P, Verplancke R, Boon P, Raedt R, Vanfleteren J. Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain. MICROMACHINES 2020; 12:38. [PMID: 33396287 PMCID: PMC7824489 DOI: 10.3390/mi12010038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 12/25/2022]
Abstract
Epilepsy is a chronic, neurological disorder affecting millions of people every year. The current available pharmacological and surgical treatments are lacking in overall efficacy and cause side-effects like cognitive impairment, depression, tremor, abnormal liver and kidney function. In recent years, the application of optogenetic implants have shown promise to target aberrant neuronal circuits in epilepsy with the advantage of both high spatial and temporal resolution and high cell-specificity, a feature that could tackle both the efficacy and side-effect problems in epilepsy treatment. Optrodes consist of electrodes to record local field potentials and an optical component to modulate neurons via activation of opsin expressed by these neurons. The goal of optogenetics in epilepsy is to interrupt seizure activity in its earliest state, providing a so-called closed-loop therapeutic intervention. The chronic implantation in vivo poses specific demands for the engineering of therapeutic optrodes. Enzymatic degradation and glial encapsulation of implants may compromise long-term recording and sufficient illumination of the opsin-expressing neural tissue. Engineering efforts for optimal optrode design have to be directed towards limitation of the foreign body reaction by reducing the implant's elastic modulus and overall size, while still providing stable long-term recording and large-area illumination, and guaranteeing successful intracerebral implantation. This paper presents an overview of the challenges and recent advances in the field of electrode design, neural-tissue illumination, and neural-probe implantation, with the goal of identifying a suitable candidate to be incorporated in a therapeutic approach for long-term treatment of epilepsy patients.
Collapse
Affiliation(s)
- Bram Vandekerckhove
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Jeroen Missinne
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Kristl Vonck
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Pieter Bauwens
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Rik Verplancke
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Paul Boon
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Robrecht Raedt
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Jan Vanfleteren
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| |
Collapse
|
17
|
Apollo NV, Murphy B, Prezelski K, Driscoll N, Richardson AG, Lucas TH, Vitale F. Gels, jets, mosquitoes, and magnets: a review of implantation strategies for soft neural probes. J Neural Eng 2020; 17:041002. [PMID: 32759476 PMCID: PMC8152109 DOI: 10.1088/1741-2552/abacd7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Implantable neuroelectronic interfaces have enabled breakthrough advances in the clinical diagnosis and treatment of neurological disorders, as well as in fundamental studies of brain function, behavior, and disease. Intracranial electroencephalography (EEG) mapping with stereo-EEG (sEEG) depth electrodes is routinely adopted for precise epilepsy diagnostics and surgical treatment, while deep brain stimulation has become the standard of care for managing movement disorders. Intracortical microelectrode arrays for high-fidelity recordings of neural spiking activity have led to impressive demonstrations of the power of brain-machine interfaces for motor and sensory functional recovery. Yet, despite the rapid pace of technology development, the issue of establishing a safe, long-term, stable, and functional interface between neuroelectronic devices and the host brain tissue still remains largely unresolved. A body of work spanning at least the last 15 years suggests that safe, chronic integration between invasive electrodes and the brain requires a close match between the mechanical properties of man-made components and the neural tissue. In other words, the next generation of invasive electrodes should be soft and compliant, without sacrificing biological and chemical stability. Soft neuroelectronic interfaces, however, pose a new and significant surgical challenge: bending and buckling during implantation that can preclude accurate and safe device placement. In this topical review, we describe the next generation of soft electrodes and the surgical implantation methods for safe and precise insertion into brain structures. We provide an overview of the most recent innovations in the field of insertion strategies for flexible neural electrodes such as dissolvable or biodegradable carriers, microactuators, biologically-inspired support structures, and electromagnetic drives. In our analysis, we also highlight approaches developed in different fields, such as robotic surgery, which could be potentially adapted and translated to the insertion of flexible neural probes.
Collapse
Affiliation(s)
- Nicholas V Apollo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Brendan Murphy
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Kayla Prezelski
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Nicolette Driscoll
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Andrew G Richardson
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Timothy H Lucas
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Flavia Vitale
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Physical Medicine & Rehabilitation, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States of America
| |
Collapse
|
18
|
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.
Collapse
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.
| |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
Deployable, liquid crystal elastomer-based intracortical probes. Acta Biomater 2020; 111:54-64. [PMID: 32428679 DOI: 10.1016/j.actbio.2020.04.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/13/2020] [Accepted: 04/17/2020] [Indexed: 11/20/2022]
Abstract
Intracortical microelectrode arrays (MEAs) are currently limited in their chronic functionality due partially to the foreign body response (FBR) that develops in regions immediately surrounding the implant (typically within 50-100 µm). Mechanically flexible, polymer-based substrates have recently been explored for MEAs as a way of minimizing the FBR caused by the chronic implantation. Nonetheless, the FBR degrades the ability of the device to record neural activity. We are motivated to develop approaches to deploy multiple recording sites away from the initial site of implantation into regions of tissue outside the FBR zone. Liquid Crystal Elastomers (LCEs) are responsive materials capable of programmable and reversible shape change. These hydrophobic materials are also non-cytotoxic and compatible with photolithography. As such, these responsive materials may be well suited to serve as substrates for smart, implantable electronics. This study explores the feasibility of LCE-based deployable intracortical MEAs. LCE intracortical probes are fabricated on a planar substrate and adopt a 3D shape after being released from the substrate. The LCE probes are then fixed in a planar configuration using polyethylene glycol (PEG). The PEG layer dissolves in physiological conditions, allowing the LCE probe to deploy post-implantation. Critically, we show that LCE intracortical probes will deploy within a brain-like agarose tissue phantom. We also show that deployment distance increases with MEA width. A finite element model was then developed to predict the deformed shape of the deployed probe when embedded in an elastic medium. Finally, LCE-based deployable intracortical MEAs were capable of maintaining electrochemical stability, recording extracellular signals from cortical neurons in vivo, and deploying recording sites greater than 100 µm from the insertion site in vivo. Taken together, these results suggest the feasibility of using LCEs to develop deployable intracortical MEAs. STATEMENT OF SIGNIFICANCE: Deployable MEAs are a recently developed class of neural interfaces that aim to shift the recording sites away from the region of insertion to minimize the negative effects of FBR on the recording performance of MEAs. In this study, we explore LCEs as a potential substrate for deployable MEAs. The novelty of this study lies in the systematic and programmable deployment offered by LCE-based intracortical MEAs. These results illustrate the feasibility and potential application of LCEs as a substrate for deployable intracortical MEAs.
Collapse
|
21
|
Holmkvist AD, Agorelius J, Forni M, Nilsson UJ, Linsmeier CE, Schouenborg J. Local delivery of minocycline-loaded PLGA nanoparticles from gelatin-coated neural implants attenuates acute brain tissue responses in mice. J Nanobiotechnology 2020; 18:27. [PMID: 32024534 PMCID: PMC7003334 DOI: 10.1186/s12951-020-0585-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 01/27/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Neural interfaces often elicit inflammatory responses and neuronal loss in the surrounding tissue which adversely affect the function and longevity of the implanted device. Minocycline, an anti-inflammatory pharmaceutics with neuroprotective properties, may be used for reducing the acute brain tissue responses after implantation. However, conventional administration routes require high doses which can cause adverse systemic side effects. Therefore, the aim of this study was to develop and evaluate a new drug-delivery-system for local and sustained administration of minocycline in the brain. METHODS Stainless steel needles insulated with Parylene-C were dip-coated with non-crosslinked gelatin and minocycline-loaded PLGA nanoparticles (MC-NPs) were incorporated into the gelatin-coatings by an absorption method and subsequently trapped by drying the gelatin. Parylene-C insulated needles coated only with gelatin were used as controls. The expression of markers for activated microglia (CD68), all microglia (CX3CR1-GFP), reactive astrocytes (GFAP), neurons (NeuN) and all cell nuclei (DAPI) surrounding the implantation sites were quantified at 3 and 7 days after implantation in mice. RESULTS MC-NPs were successfully incorporated into gelatin-coatings of neural implants by an absorption method suitable for thermosensitive drug-loads. Immunohistochemical analysis of the in vivo brain tissue responses, showed that MC-NPs significantly attenuate the activation of microglial cells without effecting the overall population of microglial cells around the implantation sites. A delayed but significant reduction of the astrocytic response was also found in comparison to control implants. No effect on neurons or total cell count was found which may suggest that the MC-NPs are non-toxic to the central nervous system. CONCLUSIONS A novel drug-nanoparticle-delivery-system was developed for neural interfaces and thermosensitive drug-loads. The local delivery of MC-NPs was shown to attenuate the acute brain tissue responses nearby an implant and therefore may be useful for improving biocompatibility of implanted neuro-electronic interfaces. The developed drug-delivery-system may potentially also be used for other pharmaceutics to provide highly localized and therefore more specific effects as compared to systemic administration.
Collapse
Affiliation(s)
- Alexander Dontsios Holmkvist
- Neuronano Research Center, Department of Experimental Medical Science, Faculty of Medicine, Lund University, Medicon Village, Building 404 A2, Scheelevägen 2, 223 81, Lund, Sweden. .,Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, 221 00, Lund, Sweden.
| | - Johan Agorelius
- Neuronano Research Center, Department of Experimental Medical Science, Faculty of Medicine, Lund University, Medicon Village, Building 404 A2, Scheelevägen 2, 223 81, Lund, Sweden.,NanoLund, Lund University, Professorsgatan 1, 223 63, Lund, Sweden
| | - Matilde Forni
- Neuronano Research Center, Department of Experimental Medical Science, Faculty of Medicine, Lund University, Medicon Village, Building 404 A2, Scheelevägen 2, 223 81, Lund, Sweden
| | - Ulf J Nilsson
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, 221 00, Lund, Sweden
| | - Cecilia Eriksson Linsmeier
- Neuronano Research Center, Department of Experimental Medical Science, Faculty of Medicine, Lund University, Medicon Village, Building 404 A2, Scheelevägen 2, 223 81, Lund, Sweden
| | - Jens Schouenborg
- Neuronano Research Center, Department of Experimental Medical Science, Faculty of Medicine, Lund University, Medicon Village, Building 404 A2, Scheelevägen 2, 223 81, Lund, Sweden. .,NanoLund, Lund University, Professorsgatan 1, 223 63, Lund, Sweden.
| |
Collapse
|
22
|
Ferguson M, Sharma D, Ross D, Zhao F. A Critical Review of Microelectrode Arrays and Strategies for Improving Neural Interfaces. Adv Healthc Mater 2019; 8:e1900558. [PMID: 31464094 PMCID: PMC6786932 DOI: 10.1002/adhm.201900558] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/25/2019] [Indexed: 12/19/2022]
Abstract
Though neural interface systems (NISs) can provide a potential solution for mitigating the effects of limb loss and central nervous system damage, the microelectrode array (MEA) component of NISs remains a significant limiting factor to their widespread clinical applications. Several strategies can be applied to MEA designs to increase their biocompatibility. Herein, an overview of NISs and their applications is provided, along with a detailed discussion of strategies for alleviating the foreign body response (FBR) and abnormalities seen at the interface of MEAs and the brain tissue following MEA implantation. Various surface modifications, including natural/synthetic surface coatings, hydrogels, and topography alterations, have shown to be highly successful in improving neural cell adhesion, reducing gliosis, and increasing MEA longevity. Different MEA surface geometries, such as those seen in the Utah and Michigan arrays, can help alleviate the resultant FBR by reducing insertion damage, while providing new avenues for improving MEA recording performance and resolution. Increasing overall flexibility of MEAs as well as reducing their stiffness is also shown to reduce MEA induced micromotion along with FBR severity. By combining multiple different properties into a single MEA, the severity and duration of an FBR postimplantation can be reduced substantially.
Collapse
Affiliation(s)
- Morgan Ferguson
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| | - Dhavan Sharma
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| | - David Ross
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| | - Feng Zhao
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| |
Collapse
|
23
|
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]
|
24
|
Guan S, Wang J, Gu X, Zhao Y, Hou R, Fan H, Zou L, Gao L, Du M, Li C, Fang Y. Elastocapillary self-assembled neurotassels for stable neural activity recordings. SCIENCE ADVANCES 2019; 5:eaav2842. [PMID: 30944856 PMCID: PMC6436924 DOI: 10.1126/sciadv.aav2842] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 02/06/2019] [Indexed: 05/18/2023]
Abstract
Implantable neural probes that are mechanically compliant with brain tissue offer important opportunities for stable neural interfaces in both basic neuroscience and clinical applications. Here, we developed a Neurotassel consisting of an array of flexible and high-aspect ratio microelectrode filaments. A Neurotassel can spontaneously assemble into a thin and implantable fiber through elastocapillary interactions when withdrawn from a molten, tissue-dissolvable polymer. Chronically implanted Neurotassels elicited minimal neuronal cell loss in the brain and enabled stable activity recordings of the same population of neurons in mice learning to perform a task. Moreover, Neurotassels can be readily scaled up to 1024 microelectrode filaments, each with a neurite-scale cross-sectional footprint of 3 × 1.5 μm2, to form implantable fibers with a total diameter of ~100 μm. With their ultrasmall sizes, high flexibility, and scalability, Neurotassels offer a new approach for stable neural activity recording and neuroprosthetics.
Collapse
Affiliation(s)
- S. Guan
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - J. Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - X. Gu
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Y. Zhao
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China
| | - R. Hou
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - H. Fan
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - L. Zou
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - L. Gao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - M. Du
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - C. Li
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- Corresponding author. (C.L.); (Y.F.)
| | - Y. Fang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- Corresponding author. (C.L.); (Y.F.)
| |
Collapse
|
25
|
Pas J, Rutz AL, Quilichini PP, Slézia A, Ghestem A, Kaszas A, Donahue MJ, Curto VF, O’Connor RP, Bernard C, Williamson A, Malliaras GG. A bilayered PVA/PLGA-bioresorbable shuttle to improve the implantation of flexible neural probes. J Neural Eng 2018; 15:065001. [DOI: 10.1088/1741-2552/aadc1d] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
26
|
Ljungquist B, Petersson P, Johansson AJ, Schouenborg J, Garwicz M. A Bit-Encoding Based New Data Structure for Time and Memory Efficient Handling of Spike Times in an Electrophysiological Setup. Neuroinformatics 2018; 16:217-229. [PMID: 29508123 PMCID: PMC5984964 DOI: 10.1007/s12021-018-9367-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Recent neuroscientific and technical developments of brain machine interfaces have put increasing demands on neuroinformatic databases and data handling software, especially when managing data in real time from large numbers of neurons. Extrapolating these developments we here set out to construct a scalable software architecture that would enable near-future massive parallel recording, organization and analysis of neurophysiological data on a standard computer. To this end we combined, for the first time in the present context, bit-encoding of spike data with a specific communication format for real time transfer and storage of neuronal data, synchronized by a common time base across all unit sources. We demonstrate that our architecture can simultaneously handle data from more than one million neurons and provide, in real time (< 25 ms), feedback based on analysis of previously recorded data. In addition to managing recordings from very large numbers of neurons in real time, it also has the capacity to handle the extensive periods of recording time necessary in certain scientific and clinical applications. Furthermore, the bit-encoding proposed has the additional advantage of allowing an extremely fast analysis of spatiotemporal spike patterns in a large number of neurons. Thus, we conclude that this architecture is well suited to support current and near-future Brain Machine Interface requirements.
Collapse
Affiliation(s)
- Bengt Ljungquist
- Neuronano Research Center, Integrative Neurophysiology and Neurotechnology, Lund University, Scheelevägen 2, 223 81 Lund, Sweden
| | - Per Petersson
- Neuronano Research Center, Integrative Neurophysiology and Neurotechnology, Lund University, Scheelevägen 2, 223 81 Lund, Sweden
- Department of Integrative Medical Biology, Umeå University, Linnéus väg 9, 901 87 Umeå, Sweden
| | - Anders J. Johansson
- Neuronano Research Center, Integrative Neurophysiology and Neurotechnology, Lund University, Scheelevägen 2, 223 81 Lund, Sweden
| | - Jens Schouenborg
- Neuronano Research Center, Integrative Neurophysiology and Neurotechnology, Lund University, Scheelevägen 2, 223 81 Lund, Sweden
| | - Martin Garwicz
- Neuronano Research Center, Integrative Neurophysiology and Neurotechnology, Lund University, Scheelevägen 2, 223 81 Lund, Sweden
| |
Collapse
|
27
|
Lecomte A, Descamps E, Bergaud C. A review on mechanical considerations for chronically-implanted neural probes. J Neural Eng 2018; 15:031001. [DOI: 10.1088/1741-2552/aa8b4f] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
28
|
Xu H, Hirschberg AW, Scholten K, Berger TW, Song D, Meng E. Acute in vivo testing of a conformal polymer microelectrode array for multi-region hippocampal recordings. J Neural Eng 2018; 15:016017. [PMID: 29044049 PMCID: PMC5792195 DOI: 10.1088/1741-2552/aa9451] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The success of a cortical prosthetic device relies upon its ability to attain resolvable spikes from many neurons in particular neural networks over long periods of time. Traditionally, lifetimes of neural recordings are greatly limited by the body's immune response against the foreign implant which causes neuronal death and glial scarring. This immune reaction is posited to be exacerbated by micromotion between the implant, which is often rigid, and the surrounding, soft brain tissue, and attenuates the quality of recordings over time. APPROACH In an attempt to minimize the foreign body response to a penetrating neural array that records from multiple brain regions, Parylene C, a flexible, biocompatible polymer was used as the substrate material for a functional, proof-of-concept neural array with a reduced elastic modulus. This probe array was designed and fabricated to have 64 electrodes positioned to match the anatomy of the rat hippocampus and allow for simultaneous recordings between two cell-body layers of interest. A dissolvable brace was used for deep-brain penetration of the flexible array. MAIN RESULTS Arrays were electrochemically characterized at the benchtop, and a novel insertion technique that restricts acute insertion injury enabled accurate target placement of four, bare, flexible arrays to greater than 4 mm deep into the rat brain. Arrays were tested acutely and in vivo recordings taken intra-operatively reveal spikes in both targeted regions of the hippocampus with spike amplitudes and noise levels similar to those recorded with microwires. Histological staining of a sham array implanted for one month reveals limited astrocytic scarring and neuronal death around the implant. SIGNIFICANCE This work represents one of the first examples of a penetrating polymer probe array that records from individual neurons in structures that lie deep within the brain.
Collapse
Affiliation(s)
- Huijing Xu
- Department of Biomedical Engineering, Center for Neural Engineering, University of Southern California, Los Angeles, CA 90089-1111, United States of America
| | | | | | | | | | | |
Collapse
|
29
|
Kumosa LS, Zetterberg V, Schouenborg J. Gelatin promotes rapid restoration of the blood brain barrier after acute brain injury. Acta Biomater 2018; 65:137-149. [PMID: 29037893 DOI: 10.1016/j.actbio.2017.10.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/27/2017] [Accepted: 10/10/2017] [Indexed: 12/25/2022]
Abstract
Gelatin coating of brain implants is known to provide considerable benefits in terms of reduced inflammatory sequalae and long-term neuroprotective effects. However, the mechanisms for gelatin's protective role in brain injury are still unknown. To address this question, cellular and molecular markers were studied with quantitative immunohistochemical microscopy at acute (<2hours, 1, 3days), intermediate (1-2 weeks) and long-term time points (6 weeks) after transient insertion of stainless steel needles into female rat cortex cerebri with or without gelatin coating. Compared to non-coated controls, injuries caused by gelatin coated needles showed a significantly faster resolution of post-stab bleeding/leakage and differential effects on different groups of microglia cells. While similar levels of matrix metalloproteinase (MMP-2 and MMP-9, two gelatinases) was found for coated and noncoated needle stabs during the first week, markedly increased levels of both MMPs was seen for gelatin-coated but not non-coated needle stabs after 2weeks. Neuronal populations and activated astrocytes were largely unaffected. In conclusion, the beneficial effects of gelatin may be the combined results of faster healing of the blood brain barrier curtailing leakage of blood borne molecules/cells into brain parenchyma and to a modulation of the microglial population response favoring restitution of the injured tissue. These findings present an important therapeutic potential for gelatin coatings in various disease, injury and surgical conditions. STATEMENT OF SIGNIFICANCE The neural interfaces field holds great promise to enable elucidation of neural information processing and to develop new implantable devices for stimulation based therapy. Currently, this field is struggling to find solutions for reducing tissue reactions to implanted micro and nanotechnology. Prior studies have recently shown that gelatin coatings lower activation of digestive microglia and mitigate the ubiquitous loss of neurons adjacent to implanted probes, both of which impede implant function. The underlying mechanisms remain to be elucidated, however. Our findings demonstrate for the first time that gelatin has a significant effect on the BBB by promoting rapid restoration of integrity after injury. Moreover, gelatin alters microglia phenotypes and modulates gelatinase activity for up to 2weeks favoring anti-inflammation and restoration of the tissue. Given the key importance of the BBB for normal brain functions, we believe our findings have substantial significance and will be highly interesting to researchers in the biomaterial field.
Collapse
|
30
|
Apollo NV, Jiang J, Cheung W, Baquier S, Lai A, Mirebedini A, Foroughi J, Wallace GG, Shivdasani MN, Prawer S, Chen S, Williams R, Cook MJ, Nayagam DAX, Garrett DJ. Development and Characterization of a Sucrose Microneedle Neural Electrode Delivery System. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/adbi.201700187] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Nicholas V. Apollo
- School of Physics; University of Melbourne; Parkville Victoria 3010 Australia
- The Bionics Institute; 384-388 Albert St. East Melbourne Victoria 3002 Australia
| | - Jonathan Jiang
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
| | - Warwick Cheung
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
| | - Sebastien Baquier
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
- Faculty of Veterinary and Agricultural Sciences; University of Melbourne; Parkville Victoria 3010 Australia
| | - Alan Lai
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
| | - Azadeh Mirebedini
- Intelligent Polymer Research Institute (IPRI); AIIM Facility; Innovation Campus; University of Wollongong; Wollongong New South Wales 2522 Australia
| | - Javad Foroughi
- Intelligent Polymer Research Institute (IPRI); AIIM Facility; Innovation Campus; University of Wollongong; Wollongong New South Wales 2522 Australia
| | - Gordon G. Wallace
- Intelligent Polymer Research Institute (IPRI); AIIM Facility; Innovation Campus; University of Wollongong; Wollongong New South Wales 2522 Australia
| | - Mohit N. Shivdasani
- The Bionics Institute; 384-388 Albert St. East Melbourne Victoria 3002 Australia
- Department of Medical Bionics; University of Melbourne; Parkville Victoria 3010 Australia
| | - Steven Prawer
- School of Physics; University of Melbourne; Parkville Victoria 3010 Australia
| | - Shou Chen
- Department of Anatomical Pathology; St Vincent's Hospital Melbourne; Fitzroy Victoria 3065 Australia
| | - Richard Williams
- Department of Anatomical Pathology; St Vincent's Hospital Melbourne; Fitzroy Victoria 3065 Australia
- Department of Pathology; University of Melbourne; Parkville Victoria 3010 Australia
| | - Mark J. Cook
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
| | - David A. X. Nayagam
- The Bionics Institute; 384-388 Albert St. East Melbourne Victoria 3002 Australia
- Department of Pathology; University of Melbourne; Parkville Victoria 3010 Australia
| | - David J. Garrett
- School of Physics; University of Melbourne; Parkville Victoria 3010 Australia
- The Bionics Institute; 384-388 Albert St. East Melbourne Victoria 3002 Australia
| |
Collapse
|
31
|
Scaini D, Ballerini L. Nanomaterials at the neural interface. Curr Opin Neurobiol 2017; 50:50-55. [PMID: 29289930 DOI: 10.1016/j.conb.2017.12.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/26/2017] [Accepted: 12/15/2017] [Indexed: 12/16/2022]
Abstract
Interfacing the nervous system with devices able to efficiently record or modulate the electrical activity of neuronal cells represents the underlying foundation of future theranostic applications in neurology and of current openings in neuroscience research. These devices, usually sensing cell activity via microelectrodes, should be characterized by safe working conditions in the biological milieu together with a well-controlled operation-life. The stable device/neuronal electrical coupling at the interface requires tight interactions between the electrode surface and the cell membrane. This neuro-electrode hybrid represents the hyphen between the soft nature of neural tissue, generating electrical signals via ion motions, and the rigid realm of microelectronics and medical devices, dealing with electrons in motion. Efficient integration of these entities is essential for monitoring, analyzing and controlling neuronal signaling but poses significant technological challenges. Improving the cell/electrode interaction and thus the interface performance requires novel engineering of (nano)materials: tuning at the nanoscale electrode's properties may lead to engineer interfacing probes that better camouflaged with their biological target. In this brief review, we highlight the most recent concepts in nanotechnologies and nanomaterials that might help reducing the mismatch between tissue and electrode, focusing on the device's mechanical properties and its biological integration with the tissue.
Collapse
Affiliation(s)
- Denis Scaini
- Scuola Internazionale Superiore di Studi Avanzati, via Bonomea, 265, 34136 Trieste, Italy; Elettra-Sincrotrone Trieste S.C.p.A. di interesse nazionale, S.S. 14, km 163,5 in AREA Science Park, 34149 Basovizza, Trieste, Italy
| | - Laura Ballerini
- Scuola Internazionale Superiore di Studi Avanzati, via Bonomea, 265, 34136 Trieste, Italy.
| |
Collapse
|
32
|
Szostak KM, Grand L, Constandinou TG. Neural Interfaces for Intracortical Recording: Requirements, Fabrication Methods, and Characteristics. Front Neurosci 2017; 11:665. [PMID: 29270103 PMCID: PMC5725438 DOI: 10.3389/fnins.2017.00665] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 11/15/2017] [Indexed: 01/30/2023] Open
Abstract
Implantable neural interfaces for central nervous system research have been designed with wire, polymer, or micromachining technologies over the past 70 years. Research on biocompatible materials, ideal probe shapes, and insertion methods has resulted in building more and more capable neural interfaces. Although the trend is promising, the long-term reliability of such devices has not yet met the required criteria for chronic human application. The performance of neural interfaces in chronic settings often degrades due to foreign body response to the implant that is initiated by the surgical procedure, and related to the probe structure, and material properties used in fabricating the neural interface. In this review, we identify the key requirements for neural interfaces for intracortical recording, describe the three different types of probes-microwire, micromachined, and polymer-based probes; their materials, fabrication methods, and discuss their characteristics and related challenges.
Collapse
Affiliation(s)
- Katarzyna M. Szostak
- Next Generation Neural Interfaces Lab, Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Imperial College London, London, United Kingdom
| | - Laszlo Grand
- Next Generation Neural Interfaces Lab, Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Imperial College London, London, United Kingdom
- Department of Neurology and Neurosurgery, Johns Hopkins University, Baltimore, MD, United States
| | - Timothy G. Constandinou
- Next Generation Neural Interfaces Lab, Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Imperial College London, London, United Kingdom
| |
Collapse
|
33
|
Ersen A, Sahin M. A PDMS-based optical waveguide for transcutaneous powering of microelectrode arrays. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:4475-4478. [PMID: 28269272 DOI: 10.1109/embc.2016.7591721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Implantable microelectrode arrays (MEAs) usually have on-site electronics that need to be powered, both in neural recording and stimulation applications. Interconnecting wires between implanted electrodes and the outside world constitute a major source of complications. Our solution to this tethering problem is to design a light waveguide that can collect the optical power transcutaneously and transmit it to the microelectrode array where it is to be converted to an electric current. A polydimethylsiloxane (PDMS)-based waveguide was fabricated and its attenuation was measured in vitro and found to be 0.36 dB/cm. The skin flap of the thenar web space in the hand was used to test the photon collection efficiency of the waveguide in diffuse light. The efficiency of the waveguide alone was 44±11% (mean±std), excluding the attenuation within the thenar skin, as measured in 13 subjects with different skin pigmentations. These preliminary results suggest that a PDMS waveguide may collect and deliver optical power with sufficient efficiencies to deep structures inside the body. Optical powering scheme can solve the tethering and breakage problems associated with metal wire connections.
Collapse
|
34
|
Lebedev MA, Nicolelis MAL. Brain-Machine Interfaces: From Basic Science to Neuroprostheses and Neurorehabilitation. Physiol Rev 2017; 97:767-837. [PMID: 28275048 DOI: 10.1152/physrev.00027.2016] [Citation(s) in RCA: 233] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Brain-machine interfaces (BMIs) combine methods, approaches, and concepts derived from neurophysiology, computer science, and engineering in an effort to establish real-time bidirectional links between living brains and artificial actuators. Although theoretical propositions and some proof of concept experiments on directly linking the brains with machines date back to the early 1960s, BMI research only took off in earnest at the end of the 1990s, when this approach became intimately linked to new neurophysiological methods for sampling large-scale brain activity. The classic goals of BMIs are 1) to unveil and utilize principles of operation and plastic properties of the distributed and dynamic circuits of the brain and 2) to create new therapies to restore mobility and sensations to severely disabled patients. Over the past decade, a wide range of BMI applications have emerged, which considerably expanded these original goals. BMI studies have shown neural control over the movements of robotic and virtual actuators that enact both upper and lower limb functions. Furthermore, BMIs have also incorporated ways to deliver sensory feedback, generated from external actuators, back to the brain. BMI research has been at the forefront of many neurophysiological discoveries, including the demonstration that, through continuous use, artificial tools can be assimilated by the primate brain's body schema. Work on BMIs has also led to the introduction of novel neurorehabilitation strategies. As a result of these efforts, long-term continuous BMI use has been recently implicated with the induction of partial neurological recovery in spinal cord injury patients.
Collapse
|
35
|
Khilwani R, Gilgunn PJ, Kozai TDY, Ong XC, Korkmaz E, Gunalan PK, Cui XT, Fedder GK, Ozdoganlar OB. Ultra-miniature ultra-compliant neural probes with dissolvable delivery needles: design, fabrication and characterization. Biomed Microdevices 2016; 18:97. [DOI: 10.1007/s10544-016-0125-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
36
|
Flexible, Penetrating Brain Probes Enabled by Advances in Polymer Microfabrication. MICROMACHINES 2016; 7:mi7100180. [PMID: 30404353 PMCID: PMC6190320 DOI: 10.3390/mi7100180] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 09/19/2016] [Indexed: 12/13/2022]
Abstract
The acquisition of high-fidelity, long-term neural recordings in vivo is critically important to advance neuroscience and brain⁻machine interfaces. For decades, rigid materials such as metal microwires and micromachined silicon shanks were used as invasive electrophysiological interfaces to neurons, providing either single or multiple electrode recording sites. Extensive research has revealed that such rigid interfaces suffer from gradual recording quality degradation, in part stemming from tissue damage and the ensuing immune response arising from mechanical mismatch between the probe and brain. The development of "soft" neural probes constructed from polymer shanks has been enabled by advancements in microfabrication; this alternative has the potential to mitigate mismatch-related side effects and thus improve the quality of recordings. This review examines soft neural probe materials and their associated microfabrication techniques, the resulting soft neural probes, and their implementation including custom implantation and electrical packaging strategies. The use of soft materials necessitates careful consideration of surgical placement, often requiring the use of additional surgical shuttles or biodegradable coatings that impart temporary stiffness. Investigation of surgical implantation mechanics and histological evidence to support the use of soft probes will be presented. The review concludes with a critical discussion of the remaining technical challenges and future outlook.
Collapse
|
37
|
Etemadi L, Mohammed M, Thorbergsson PT, Ekstrand J, Friberg A, Granmo M, Pettersson LME, Schouenborg J. Embedded Ultrathin Cluster Electrodes for Long-Term Recordings in Deep Brain Centers. PLoS One 2016; 11:e0155109. [PMID: 27159159 PMCID: PMC4861347 DOI: 10.1371/journal.pone.0155109] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/25/2016] [Indexed: 01/03/2023] Open
Abstract
Neural interfaces which allow long-term recordings in deep brain structures in awake freely moving animals have the potential of becoming highly valuable tools in neuroscience. However, the recording quality usually deteriorates over time, probably at least partly due to tissue reactions caused by injuries during implantation, and subsequently micro-forces due to a lack of mechanical compliance between the tissue and neural interface. To address this challenge, we developed a gelatin embedded neural interface comprising highly flexible electrodes and evaluated its long term recording properties. Bundles of ultrathin parylene C coated platinum electrodes (N = 29) were embedded in a hard gelatin based matrix shaped like a needle, and coated with Kollicoat™ to retard dissolution of gelatin during the implantation. The implantation parameters were established in an in vitro model of the brain (0.5% agarose). Following a craniotomy in the anesthetized rat, the gelatin embedded electrodes were stereotactically inserted to a pre-target position, and after gelatin dissolution the electrodes were further advanced and spread out in the area of the subthalamic nucleus (STN). The performance of the implanted electrodes was evaluated under anesthesia, during 8 weeks. Apart from an increase in the median-noise level during the first 4 weeks, the electrode impedance and signal-to-noise ratio of single-units remained stable throughout the experiment. Histological postmortem analysis confirmed implantation in the area of STN in most animals. In conclusion, by combining novel biocompatible implantation techniques and ultra-flexible electrodes, long-term neuronal recordings from deep brain structures with no significant deterioration of electrode function were achieved.
Collapse
Affiliation(s)
- Leila Etemadi
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Mohsin Mohammed
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail: (MM); (JS); (LP)
| | - Palmi Thor Thorbergsson
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Joakim Ekstrand
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Annika Friberg
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Marcus Granmo
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Lina M. E. Pettersson
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail: (MM); (JS); (LP)
| | - Jens Schouenborg
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail: (MM); (JS); (LP)
| |
Collapse
|
38
|
Castagnola E, Maggiolini E, Ceseracciu L, Ciarpella F, Zucchini E, De Faveri S, Fadiga L, Ricci D. pHEMA Encapsulated PEDOT-PSS-CNT Microsphere Microelectrodes for Recording Single Unit Activity in the Brain. Front Neurosci 2016; 10:151. [PMID: 27147944 PMCID: PMC4834343 DOI: 10.3389/fnins.2016.00151] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/21/2016] [Indexed: 12/18/2022] Open
Abstract
The long-term reliability of neural interfaces and stability of high-quality recordings are still unsolved issues in neuroscience research. High surface area PEDOT-PSS-CNT composites are able to greatly improve the performance of recording and stimulation for traditional intracortical metal microelectrodes by decreasing their impedance and increasing their charge transfer capability. This enhancement significantly reduces the size of the implantable device though preserving excellent electrical performances. On the other hand, the presence of nanomaterials often rises concerns regarding possible health hazards, especially when considering a clinical application of the devices. For this reason, we decided to explore the problem from a new perspective by designing and testing an innovative device based on nanostructured microspheres grown on a thin tether, integrating PEDOT-PSS-CNT nanocomposites with a soft synthetic permanent biocompatible hydrogel. The pHEMA hydrogel preserves the electrochemical performance and high quality recording ability of PEDOT-PSS-CNT coated devices, reduces the mechanical mismatch between soft brain tissue and stiff devices and also avoids direct contact between the neural tissue and the nanocomposite, by acting as a biocompatible protective barrier against potential nanomaterial detachment. Moreover, the spherical shape of the electrode together with the surface area increase provided by the nanocomposite deposited on it, maximize the electrical contact and may improve recording stability over time. These results have a good potential to contribute to fulfill the grand challenge of obtaining stable neural interfaces for long-term applications.
Collapse
Affiliation(s)
- Elisa Castagnola
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
| | - Emma Maggiolini
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
| | - Luca Ceseracciu
- Department of Smart Materials, Istituto Italiano di TecnologiaGenova, Italy
| | | | - Elena Zucchini
- Section of Human Physiology, University of FerraraFerrara, Italy
| | - Sara De Faveri
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
| | - Luciano Fadiga
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
- Section of Human Physiology, University of FerraraFerrara, Italy
| | - Davide Ricci
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
| |
Collapse
|
39
|
Piret G, Prinz CN. Could the use of nanowire structures overcome some of the current limitations of brain electrode implants? Nanomedicine (Lond) 2016; 11:745-7. [DOI: 10.2217/nnm.16.23] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Gaëlle Piret
- Clinatec laboratory, Biomedical Research Center Edmond J. Safra, INSERM/CEA-léti/UJF/CHU, 38054 Grenoble Cedex 09, France
| | - Christelle N Prinz
- Division of Solid State Physics and NanoLund, Lund University, 221 00 Lund, Sweden
- Neuronano Research Center, Lund University, 223 81 Lund, Sweden
| |
Collapse
|
40
|
Prodanov D, Delbeke J. Mechanical and Biological Interactions of Implants with the Brain and Their Impact on Implant Design. Front Neurosci 2016; 10:11. [PMID: 26903786 PMCID: PMC4746296 DOI: 10.3389/fnins.2016.00011] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 01/11/2016] [Indexed: 11/26/2022] Open
Abstract
Neural prostheses have already a long history and yet the cochlear implant remains the only success story about a longterm sensory function restoration. On the other hand, neural implants for deep brain stimulation are gaining acceptance for variety of disorders including Parkinsons disease and obsessive-compulsive disorder. It is anticipated that the progress in the field has been hampered by a combination of technological and biological factors, such as the limited understanding of the longterm behavior of implants, unreliability of devices, biocompatibility of the implants among others. While the field's understanding of the cell biology of interactions at the biotic-abiotic interface has improved, relatively little attention has been paid on the mechanical factors (stress, strain), and hence on the geometry that can modulate it. This focused review summarizes the recent progress in the understanding of the mechanisms of mechanical interaction between the implants and the brain. The review gives an overview of the factors by which the implants interact acutely and chronically with the tissue: blood-brain barrier (BBB) breach, vascular damage, micromotions, diffusion etc. We propose some design constraints to be considered in future studies. Aspects of the chronic cell-implant interaction will be discussed in view of the chronic local inflammation and the ways of modulating it.
Collapse
Affiliation(s)
- Dimiter Prodanov
- Department of Environment, Health and Safety, ImecLeuven, Belgium
- Neuroscience Research FlandersLeuven, Belgium
| | - Jean Delbeke
- LCEN3, Department of Neurology, Institute of Neuroscience, Ghent UniversityGhent, Belgium
| |
Collapse
|