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Ghazal M, Susloparova A, Lefebvre C, Daher Mansour M, Ghodhbane N, Melot A, Scholaert C, Guérin D, Janel S, Barois N, Colin M, Buée L, Yger P, Halliez S, Coffinier Y, Pecqueur S, Alibart F. Electropolymerization processing of side-chain engineered EDOT for high performance microelectrode arrays. Biosens Bioelectron 2023; 237:115538. [PMID: 37506488 DOI: 10.1016/j.bios.2023.115538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 07/04/2023] [Accepted: 07/16/2023] [Indexed: 07/30/2023]
Abstract
Microelectrode Arrays (MEAs) are popular tools for in vitro extracellular recording. They are often optimized by surface engineering to improve affinity with neurons and guarantee higher recording quality and stability. Recently, PEDOT:PSS has been used to coat microelectrodes due to its good biocompatibility and low impedance, which enhances neural coupling. Herein, we investigate on electro-co-polymerization of EDOT with its triglymated derivative to control valence between monomer units and hydrophilic functions on a conducting polymer. Molecular packing, cation complexation, dopant stoichiometry are governed by the glycolation degree of the electro-active coating of the microelectrodes. Optimal monomer ratio allows fine-tuning the material hydrophilicity and biocompatibility without compromising the electrochemical impedance of microelectrodes nor their stability while interfaced with a neural cell culture. After incubation, sensing readout on the modified electrodes shows higher performances with respect to unmodified electropolymerized PEDOT, with higher signal-to-noise ratio (SNR) and higher spike counts on the same neural culture. Reported SNR values are superior to that of state-of-the-art PEDOT microelectrodes and close to that of state-of-the-art 3D microelectrodes, with a reduced fabrication complexity. Thanks to this versatile technique and its impact on the surface chemistry of the microelectrode, we show that electro-co-polymerization trades with many-compound properties to easily gather them into single macromolecular structures. Applied on sensor arrays, it holds great potential for the customization of neurosensors to adapt to environmental boundaries and to optimize extracted sensing features.
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Affiliation(s)
- Mahdi Ghazal
- Institute of Electronics, Microelectronics and Nanotechnology (IEMN, UMR 8520) | Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, 59000, Lille, France
| | - Anna Susloparova
- Institute of Electronics, Microelectronics and Nanotechnology (IEMN, UMR 8520) | Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, 59000, Lille, France
| | - Camille Lefebvre
- University of Lille, Inserm, CHU Lille, Lille Neuroscience & Cognition, UMR-S1172, Lille, France
| | - Michel Daher Mansour
- Institute of Electronics, Microelectronics and Nanotechnology (IEMN, UMR 8520) | Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, 59000, Lille, France
| | - Najami Ghodhbane
- Institute of Electronics, Microelectronics and Nanotechnology (IEMN, UMR 8520) | Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, 59000, Lille, France
| | - Alexis Melot
- Laboratoire Nanotechnologies & Nanosystèmes (LN2, UMI 3463) | CNRS, Université de Sherbrooke, J1X0A5, Sherbrooke, Canada
| | - Corentin Scholaert
- Institute of Electronics, Microelectronics and Nanotechnology (IEMN, UMR 8520) | Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, 59000, Lille, France
| | - David Guérin
- Institute of Electronics, Microelectronics and Nanotechnology (IEMN, UMR 8520) | Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, 59000, Lille, France
| | - Sébastien Janel
- Université de Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR9017, CIIL-Center for Infection and Immunity of Lille, F-59000, Lille, France
| | - Nicolas Barois
- Université de Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR9017, CIIL-Center for Infection and Immunity of Lille, F-59000, Lille, France
| | - Morvane Colin
- University of Lille, Inserm, CHU Lille, Lille Neuroscience & Cognition, UMR-S1172, Lille, France
| | - Luc Buée
- University of Lille, Inserm, CHU Lille, Lille Neuroscience & Cognition, UMR-S1172, Lille, France
| | - Pierre Yger
- Plasticity & SubjectivitY Team, Lille Neuroscience & Cognition Research Centre, University of Lille, INSERM U1172, Lille, France; Institut de La Vision, Sorbonne Université, INSERM, Centre National de La Recherche Scientifique, Paris, France
| | - Sophie Halliez
- University of Lille, Inserm, CHU Lille, Lille Neuroscience & Cognition, UMR-S1172, Lille, France
| | - Yannick Coffinier
- Institute of Electronics, Microelectronics and Nanotechnology (IEMN, UMR 8520) | Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, 59000, Lille, France.
| | - Sébastien Pecqueur
- Institute of Electronics, Microelectronics and Nanotechnology (IEMN, UMR 8520) | Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, 59000, Lille, France.
| | - Fabien Alibart
- Institute of Electronics, Microelectronics and Nanotechnology (IEMN, UMR 8520) | Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, 59000, Lille, France; Laboratoire Nanotechnologies & Nanosystèmes (LN2, UMI 3463) | CNRS, Université de Sherbrooke, J1X0A5, Sherbrooke, Canada
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Jeong H, Kim J, Seo JM, Neviani A. Neurostimulators for high-resolution artificial retina: ASIC design challenges and solutions. J Neural Eng 2022; 19. [PMID: 36374010 DOI: 10.1088/1741-2552/aca262] [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: 06/28/2022] [Accepted: 11/14/2022] [Indexed: 11/16/2022]
Abstract
Objective.Neurostimulator is one of the most important part in artificial retina design. In this paper, we discuss the main challenges in the design of application-specific integrated circuit for high-resolution artificial retina and suggest corresponding solutions.Approach. Problems in the design of the neurostimulator for the existing artificial retina have not been solved yet are analyzed and solutions are presented. For verification of the solutions, mathematical proof, MATLAB and Ansys simulations are used.Main results. The drawbacks of resorting to a high-voltage complementary metal oxide semiconductor (CMOS) process to deal with the large voltage compliance demanded by the stimulator output stage are pointed out, and an alternative approach based on a circuit that switches the voltage of the common reference electrode is proposed to overcome. The necessity of an active discharge circuit to remove the residual charge of electrodes caused by an unbalanced stimulus is investigated. We present a circuit analysis showing that the use of a passive discharge circuit is sufficient to suppress problematic direct current in most situations. Finally, possible restrictions on input and output (I/O) count are investigated by estimating the resistive-capacitive delay caused by the interconnection between the I/O pad and the microelectrode array.Significance. The results of this paper clarified the problems currently faced by neurostimulator design for the artificial retina. Through the solutions presented in this study, circuits with more competitiveness in power and area consumption can be designed.
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Affiliation(s)
- Hyunbeen Jeong
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea
| | - Jisung Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea
| | - Jong-Mo Seo
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea.,Department of Ophthalmology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Andrea Neviani
- Department of Information Engineering, University of Padova, Padova, Italy
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Geramifard N, Lawson J, Cogan SF, Black BJ. A Novel 3D Helical Microelectrode Array for In Vitro Extracellular Action Potential Recording. MICROMACHINES 2022; 13:1692. [PMID: 36296045 PMCID: PMC9611359 DOI: 10.3390/mi13101692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/25/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Recent advances in cell and tissue engineering have enabled long-term three-dimensional (3D) in vitro cultures of human-derived neuronal tissues. Analogous two-dimensional (2D) tissue cultures have been used for decades in combination with substrate integrated microelectrode arrays (MEA) for pharmacological and toxicological assessments. While the phenotypic and cytoarchitectural arguments for 3D culture are clear, 3D MEA technologies are presently inadequate. This is mostly due to the technical challenge of creating vertical electrical conduction paths (or 'traces') using standardized biocompatible materials and fabrication techniques. Here, we have circumvented that challenge by designing and fabricating a novel helical 3D MEA comprised of polyimide, amorphous silicon carbide (a-SiC), gold/titanium, and sputtered iridium oxide films (SIROF). Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) testing confirmed fully-fabricated MEAs should be capable of recording extracellular action potentials (EAPs) with high signal-to-noise ratios (SNR). We then seeded induced pluripotent stems cell (iPSC) sensory neurons (SNs) in a 3D collagen-based hydrogel integrated with the helical MEAs and recorded EAPs for up to 28 days in vitro from across the MEA volume. Importantly, this highly adaptable design does not intrinsically limit cell/tissue type, channel count, height, or total volume.
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Affiliation(s)
- Negar Geramifard
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Jennifer Lawson
- Biomedical Engineering Department, Francis College of Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Stuart F. Cogan
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Bryan James Black
- Biomedical Engineering Department, Francis College of Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USA
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Vėbraitė I, Hanein Y. Soft Devices for High-Resolution Neuro-Stimulation: The Interplay Between Low-Rigidity and Resolution. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:675744. [PMID: 35047928 PMCID: PMC8757739 DOI: 10.3389/fmedt.2021.675744] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/14/2021] [Indexed: 12/27/2022] Open
Abstract
The field of neurostimulation has evolved over the last few decades from a crude, low-resolution approach to a highly sophisticated methodology entailing the use of state-of-the-art technologies. Neurostimulation has been tested for a growing number of neurological applications, demonstrating great promise and attracting growing attention in both academia and industry. Despite tremendous progress, long-term stability of the implants, their large dimensions, their rigidity and the methods of their introduction and anchoring to sensitive neural tissue remain challenging. The purpose of this review is to provide a concise introduction to the field of high-resolution neurostimulation from a technological perspective and to focus on opportunities stemming from developments in materials sciences and engineering to reduce device rigidity while optimizing electrode small dimensions. We discuss how these factors may contribute to smaller, lighter, softer and higher electrode density devices.
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Affiliation(s)
- Ieva Vėbraitė
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yael Hanein
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
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Woo H, Kim S, Nam H, Choi W, Shin K, Kim K, Yoon S, Kim GH, Kim J, Lim G. Au Hierarchical Nanostructure-Based Surface Modification of Microelectrodes for Improved Neural Signal Recording. Anal Chem 2021; 93:11765-11774. [PMID: 34387479 DOI: 10.1021/acs.analchem.1c02168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microelectrodes are widely used for neural signal analysis because they can record high-resolution signals. In general, the smaller the size of the microelectrode for obtaining a high-resolution signal, the higher the impedance and noise value of the electrodes. Therefore, to improve the signal-to-noise ratio (SNR) of neural signals, it is important to develop microelectrodes with low impedance and noise. In this research, an Au hierarchical nanostructure (AHN) was deposited to improve the electrochemical surface area (ECSA) of a microelectrode. Au nanostructures on different scales were deposited on the electrode surface in a hierarchical structure using an electrochemical deposition method. The AHN-modified microelectrode exhibited an average of 80% improvement in impedance compared to a bare microelectrode. Through electrochemical impedance spectroscopy analysis and impedance equivalent circuit modeling, the increase in the ECSA due to the AHN was confirmed. After evaluating the cell cytotoxicity of the AHN-modified microelectrode through an in vitro test, neural signals from rats were obtained in in vivo experiments. The AHN-modified microelectrode exhibited an approximate 9.79 dB improvement in SNR compared to the bare microelectrode. This surface modification technology is a post-treatment strategy used for existing fabricated electrodes, so it can be applied to microelectrode arrays and nerve electrodes made from various structures and materials.
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Affiliation(s)
| | | | | | - Wonsuk Choi
- Center for Bionics, Korea Institute of Science and Technology (KIST), 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Kumjae Shin
- Construction Equipment Technology Center, Korea Institute of Industrial Technology (KITECH), 288-1, Daehak-ri, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 38408, Republic of Korea
| | | | | | - Geon Hwee Kim
- School of Mechanical Engineering, Chungbuk National University (CBNU), 1, Chungdae-ro, Seowon-gu, Cheongju-si, Chungcheongbuk-do 28644, Republic of Korea
| | - Jinseok Kim
- Center for Bionics, Korea Institute of Science and Technology (KIST), 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea
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Passaro AP, Stice SL. Electrophysiological Analysis of Brain Organoids: Current Approaches and Advancements. Front Neurosci 2021; 14:622137. [PMID: 33510616 PMCID: PMC7835643 DOI: 10.3389/fnins.2020.622137] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/11/2020] [Indexed: 12/23/2022] Open
Abstract
Brain organoids, or cerebral organoids, have become widely used to study the human brain in vitro. As pluripotent stem cell-derived structures capable of self-organization and recapitulation of physiological cell types and architecture, brain organoids bridge the gap between relatively simple two-dimensional human cell cultures and non-human animal models. This allows for high complexity and physiological relevance in a controlled in vitro setting, opening the door for a variety of applications including development and disease modeling and high-throughput screening. While technologies such as single cell sequencing have led to significant advances in brain organoid characterization and understanding, improved functional analysis (especially electrophysiology) is needed to realize the full potential of brain organoids. In this review, we highlight key technologies for brain organoid development and characterization, then discuss current electrophysiological methods for brain organoid analysis. While electrophysiological approaches have improved rapidly for two-dimensional cultures, only in the past several years have advances been made to overcome limitations posed by the three-dimensionality of brain organoids. Here, we review major advances in electrophysiological technologies and analytical methods with a focus on advances with applicability for brain organoid analysis.
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Affiliation(s)
- Austin P. Passaro
- Regenerative Bioscience Center, University of Georgia, Athens, GA, United States
- Division of Neuroscience, Biomedical & Health Sciences Institute, University of Georgia, Athens, GA, United States
| | - Steven L. Stice
- Regenerative Bioscience Center, University of Georgia, Athens, GA, United States
- Division of Neuroscience, Biomedical & Health Sciences Institute, University of Georgia, Athens, GA, United States
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States
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Boehler C, Vieira DM, Egert U, Asplund M. NanoPt-A Nanostructured Electrode Coating for Neural Recording and Microstimulation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:14855-14865. [PMID: 32162910 DOI: 10.1021/acsami.9b22798] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bioelectronic devices, interfacing neural tissue for therapeutic, diagnostic, or rehabilitation purposes, rely on small electrode contacts in order to achieve highly sophisticated communication at the neural interface. Reliable recording and safe stimulation with small electrodes, however, are limited when conventional electrode metallizations are used, demanding the development of new materials to enable future progress within bioelectronics. In this study, we present a versatile process for the realization of nanostructured platinum (nanoPt) coatings with a high electrochemically active surface area, showing promising biocompatibility and providing low impedance, high charge injection capacity, and outstanding long-term stability both for recording and stimulation. The proposed electrochemical fabrication process offers exceptional control over the nanoPt deposition, allowing the realization of specific coating morphologies such as small grains, pyramids, or nanoflakes, and can moreover be scaled up to wafer level or batch fabrication under economic process conditions. The suitability of nanoPt as a coating for neural interfaces is here demonstrated, in vitro and in vivo, revealing superior stimulation performance under chronic conditions. Thus, nanoPt offers promising qualities as an advanced neural interface coating which moreover extends to the numerous application fields where a large (electro)chemically active surface area contributes to increased efficiency.
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Affiliation(s)
- Christian Boehler
- Department of Microsystems Engineering (IMTEK)-ElectroActive Coatings Group, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
| | - Diego M Vieira
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
- Department of Microsystems Engineering (IMTEK)-Laboratory for Biomicrotechnology, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- Bernstein Center Freiburg (BCF), University of Freiburg, 79110 Freiburg, Germany
| | - Ulrich Egert
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
- Department of Microsystems Engineering (IMTEK)-Laboratory for Biomicrotechnology, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- Bernstein Center Freiburg (BCF), University of Freiburg, 79110 Freiburg, Germany
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK)-ElectroActive Coatings Group, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
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Atmaramani R, Chakraborty B, Rihani RT, Usoro J, Hammack A, Abbott J, Nnoromele P, Black BJ, Pancrazio JJ, Cogan SF. Ruthenium oxide based microelectrode arrays for in vitro and in vivo neural recording and stimulation. Acta Biomater 2020; 101:565-574. [PMID: 31678740 DOI: 10.1016/j.actbio.2019.10.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/22/2019] [Accepted: 10/28/2019] [Indexed: 10/25/2022]
Abstract
We have characterized the in vitro and in vivo extracellular neural recording and stimulation properties of ruthenium oxide (RuOx) based microelectrodes. Cytotoxicity and functional neurotoxicity assays were carried out to confirm the in vitro biocompatibility of RuOx. Material extract assays, in accordance to ISO protocol "10993-5: Biological evaluation of medical devices", revealed no significant effect on neuronal cell viability or the functional activity of cortical networks. In vitro microelectrode arrays (MEAs), with indium tin oxide (ITO) sites modified with sputtered iridium oxide (IrOx) and RuOx in a single array, were developed for a direct comparison of electrochemical and recording performance of RuOx to ITO and IrOx deposited microelectrode sites. The impedance of the RuOx-coated electrodes measured by electrochemical impedance spectroscopy was notably lower than that of ITO electrodes, resulting in robust extracellular recordings from cortical networks in vitro. We found comparable signal-to-noise ratios (SNRs) for RuOx and IrOx, both significantly higher than the SNR for ITO. RuOx-based MEAs were also fabricated and implanted in the rat motor cortex to demonstrate manufacturability of the RuOx processing and acute recording capabilities in vivo. We observed single-unit extracellular action potentials with a SNR >22, representing a first step for neurophysiological recordings in vivo with RuOx based microelectrodes. STATEMENT OF SIGNIFICANCE: A critical challenge in neural interface technology is the development of microelectrodes that have recording and electrical stimulation capabilities suitable for bidirectional communication between the external electronic device and the nervous system. The present study explores the feasibility and functional capabilities of ruthenium oxide microelectrodes as a neural interface. Significant improvement in electrochemical properties and neuronal recordings are reported when compared to commercially available indium tin oxide and was similar to that of iridium oxide electrodes. The data demonstrate the potential for future development of chronic neural interfaces using ruthenium oxide based microelectrodes for recording and stimulation.
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Koklu A, Ajaev V, Beskok A. Self-Similar Response of Electrode Polarization for Binary Electrolytes in Parallel Plate Capacitor Systems. Anal Chem 2019; 91:11231-11239. [DOI: 10.1021/acs.analchem.9b02162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Anil Koklu
- Department of Mechanical Engineering, Southern Methodist University, Dallas, Texas 75205, United States
| | - Vladimir Ajaev
- Department of Mathematics, Southern Methodist University, Dallas, Texas 75275, United States
| | - Ali Beskok
- Department of Mechanical Engineering, Southern Methodist University, Dallas, Texas 75205, United States
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