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Shoup AM, Porwal N, Fakharian MA, Hage P, Orozco SP, Shadmehr R. Rejuvenating silicon probes for acute neurophysiology. J Neurophysiol 2024; 132:308-315. [PMID: 38865216 DOI: 10.1152/jn.00121.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 06/11/2024] [Accepted: 06/11/2024] [Indexed: 06/14/2024] Open
Abstract
Neurophysiological recording with a new probe often yields better signal quality than with a used probe. Why does the signal quality degrade after only a few experiments? Here, we considered silicon probes in which the contacts are densely packed, and each contact is coated with a conductive polymer that increases its surface area. We tested 12 Cambridge Neurotech silicon probes during 61 recording sessions from the brain of three marmosets. Out of the box, each probe arrived with an electrodeposited polymer coating on 64 gold contacts and an impedance of around 50 kΩ. With repeated use, the impedance increased and there was a corresponding decrease in the number of well-isolated neurons. Imaging of the probes suggested that the reduction in signal quality was due to a gradual loss of the polymer coating. To rejuvenate the probes, we first stripped the contacts, completely removing their polymer coating, and then recoated them in a solution of 10 mM 3,4-Ethylenedioxythiophene (EDOT) monomer with 11 mM Poly(sodium 4-styrenesulfonate) (PSS) using a current density of about 3 mA/cm2 for 30 s. This recoating process not only returned probe impedance to around 50 kΩ but also yielded significantly improved signal quality during neurophysiological recordings. Thus, insertion into the brain promoted the loss of the polymer that coated the contacts of the silicon probes. This led to degradation of signal quality, but recoating rejuvenated the probes.NEW & NOTEWORTHY With repeated use, a silicon probe's ability to isolate neurons degrades. As a result, the probe is often discarded after only a handful of uses. Here, we demonstrate a major source of this problem and then produce a solution to rejuvenate the probes.
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Affiliation(s)
- Alden M Shoup
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Natasha Porwal
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Mohammad Amin Fakharian
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Paul Hage
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Simon P Orozco
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Reza Shadmehr
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
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2
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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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3
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Muguet I, Maziz A, Mathieu F, Mazenq L, Larrieu G. Combining PEDOT:PSS Polymer Coating with Metallic 3D Nanowires Electrodes to Achieve High Electrochemical Performances for Neuronal Interfacing Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2302472. [PMID: 37385261 DOI: 10.1002/adma.202302472] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/18/2023] [Accepted: 05/26/2023] [Indexed: 07/01/2023]
Abstract
This study presents a novel approach to improve the performance of microelectrode arrays (MEAs) used for electrophysiological studies of neuronal networks. The integration of 3D nanowires (NWs) with MEAs increases the surface-to-volume ratio, which enables subcellular interactions and high-resolution neuronal signal recording. However, these devices suffer from high initial interface impedance and limited charge transfer capacity due to their small effective area. To overcome these limitations, the integration of conductive polymer coatings, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) is investigated as a mean of improving the charge transfer capacity and biocompatibility of MEAs. The study combines platinum silicide-based metallic 3D nanowires electrodes with electrodeposited PEDOT:PSS coatings to deposit ultra-thin (<50 nm) layers of conductive polymer onto metallic electrodes with very high selectivity. The polymer-coated electrodes were fully characterized electrochemically and morphologically to establish a direct relationship between synthesis conditions, morphology, and conductive features. Results show that PEDOT-coated electrodes exhibit thickness-dependent improved stimulation and recording performances, offering new perspectives for neuronal interfacing with optimal cell engulfment to enable the study of neuronal activity with acute spatial and signal resolution at the sub-cellular level.
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Affiliation(s)
- Ines Muguet
- LAAS-CNRS, Université de Toulouse, CNRS, 7 avenue du colonel Roche, Toulouse, F-31400, France
| | - Ali Maziz
- LAAS-CNRS, Université de Toulouse, CNRS, 7 avenue du colonel Roche, Toulouse, F-31400, France
| | - Fabrice Mathieu
- LAAS-CNRS, Université de Toulouse, CNRS, 7 avenue du colonel Roche, Toulouse, F-31400, France
| | - Laurent Mazenq
- LAAS-CNRS, Université de Toulouse, CNRS, 7 avenue du colonel Roche, Toulouse, F-31400, France
| | - Guilhem Larrieu
- LAAS-CNRS, Université de Toulouse, CNRS, 7 avenue du colonel Roche, Toulouse, F-31400, France
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4
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Steins H, Mierzejewski M, Brauns L, Stumpf A, Kohler A, Heusel G, Corna A, Herrmann T, Jones PD, Zeck G, von Metzen R, Stieglitz T. A flexible protruding microelectrode array for neural interfacing in bioelectronic medicine. MICROSYSTEMS & NANOENGINEERING 2022; 8:131. [PMID: 36568135 PMCID: PMC9772315 DOI: 10.1038/s41378-022-00466-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/23/2022] [Accepted: 07/07/2022] [Indexed: 05/31/2023]
Abstract
Recording neural signals from delicate autonomic nerves is a challenging task that requires the development of a low-invasive neural interface with highly selective, micrometer-sized electrodes. This paper reports on the development of a three-dimensional (3D) protruding thin-film microelectrode array (MEA), which is intended to be used for recording low-amplitude neural signals from pelvic nervous structures by penetrating the nerves transversely to reduce the distance to the axons. Cylindrical gold pillars (Ø 20 or 50 µm, ~60 µm height) were fabricated on a micromachined polyimide substrate in an electroplating process. Their sidewalls were insulated with parylene C, and their tips were optionally modified by wet etching and/or the application of a titanium nitride (TiN) coating. The microelectrodes modified by these combined techniques exhibited low impedances (~7 kΩ at 1 kHz for Ø 50 µm microelectrode with the exposed surface area of ~5000 µm²) and low intrinsic noise levels. Their functionalities were evaluated in an ex vivo pilot study with mouse retinae, in which spontaneous neuronal spikes were recorded with amplitudes of up to 66 µV. This novel process strategy for fabricating flexible, 3D neural interfaces with low-impedance microelectrodes has the potential to selectively record neural signals from not only delicate structures such as retinal cells but also autonomic nerves with improved signal quality to study neural circuits and develop stimulation strategies in bioelectronic medicine, e.g., for the control of vital digestive functions.
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Affiliation(s)
- Helen Steins
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Michael Mierzejewski
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Lisa Brauns
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Angelika Stumpf
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Alina Kohler
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Gerhard Heusel
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Andrea Corna
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- Institute of Biomedical Electronics, TU Wien, Vienna, Austria
| | - Thoralf Herrmann
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Peter D. Jones
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Günther Zeck
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- Institute of Biomedical Electronics, TU Wien, Vienna, Austria
| | - Rene von Metzen
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Thomas Stieglitz
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
- Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
- BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
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5
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Ruggiero A, Criscuolo V, Grasselli S, Bruno U, Ausilio C, Bovio CL, Bettucci O, Santoro F. Two-photon polymerization lithography enabling the fabrication of PEDOT:PSS 3D structures for bioelectronic applications. Chem Commun (Camb) 2022; 58:9790-9793. [PMID: 35971788 DOI: 10.1039/d2cc03152c] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conductive 3D platforms have gained increasing attention in bioelectronics thanks to the improvement in the cell-chip coupling. PEDOT:PSS is nowadays widely employed in bioelectronic applications thanks to its electrical and mechanical properties. In this work, an innovative fabrication method for the realization of PEDOT:PSS-based conductive micropillars and 3D cage-like structures is presented, combining two-photon lithography and electrodeposition techniques.
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Affiliation(s)
- Amedeo Ruggiero
- Tissue Electronics, Istituto Italiano di Tecnologia, 80125 Naples, Italy. .,Faculty of Electrical Engineering and IT, RWTH Aachen, 52074, Germany.,Institute for Biological Information Processing-Bioelectronics, Forschungszentrum Juelich, 52428, Germany.
| | - Valeria Criscuolo
- Tissue Electronics, Istituto Italiano di Tecnologia, 80125 Naples, Italy.
| | - Sara Grasselli
- Tissue Electronics, Istituto Italiano di Tecnologia, 80125 Naples, Italy.
| | - Ugo Bruno
- Tissue Electronics, Istituto Italiano di Tecnologia, 80125 Naples, Italy. .,Dipartimento di Chimica, Materiali e Produzione Industriale, Università di Napoli Federico II, 80125 Naples, Italy
| | - Chiara Ausilio
- Tissue Electronics, Istituto Italiano di Tecnologia, 80125 Naples, Italy.
| | - Claudia Latte Bovio
- Tissue Electronics, Istituto Italiano di Tecnologia, 80125 Naples, Italy. .,Dipartimento di Chimica, Materiali e Produzione Industriale, Università di Napoli Federico II, 80125 Naples, Italy
| | - Ottavia Bettucci
- Tissue Electronics, Istituto Italiano di Tecnologia, 80125 Naples, Italy.
| | - Francesca Santoro
- Tissue Electronics, Istituto Italiano di Tecnologia, 80125 Naples, Italy. .,Faculty of Electrical Engineering and IT, RWTH Aachen, 52074, Germany.,Institute for Biological Information Processing-Bioelectronics, Forschungszentrum Juelich, 52428, Germany.
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6
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Leva F, Palestri P, Selmi L. Multiscale simulation analysis of passive and active micro/nanoelectrodes for CMOS-based in vitro neural sensing devices. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210013. [PMID: 35658681 DOI: 10.1098/rsta.2021.0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/14/2021] [Indexed: 06/15/2023]
Abstract
Neuron and neural network studies are remarkably fostered by novel stimulation and recording systems, which often make use of biochips fabricated with advanced electronic technologies and, notably, micro- and nanoscale complementary metal-oxide semiconductor (CMOS). Models of the transduction mechanisms involved in the sensor and recording of the neuron activity are useful to optimize the sensing device architecture and its coupling to the readout circuits, as well as to interpret the measured data. Starting with an overview of recently published integrated active and passive micro/nanoelectrode sensing devices for in vitro studies fabricated with modern (CMOS-based) micro-nano technology, this paper presents a mixed-mode device-circuit numerical-analytical multiscale and multiphysics simulation methodology to describe the neuron-sensor coupling, suitable to derive useful design guidelines. A few representative structures and coupling conditions are analysed in more detail in terms of the most relevant electrical figures of merit including signal-to-noise ratio. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.
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Affiliation(s)
- Federico Leva
- Dipartimento di ingegneria Enzo Ferrari, University of Modena and Reggio Emilia, Modena, Italy
| | - Pierpaolo Palestri
- Polytechnical Department of Engineering and Architecture, University of Udine, Udine, Italy
| | - Luca Selmi
- Dipartimento di ingegneria Enzo Ferrari, University of Modena and Reggio Emilia, Modena, Italy
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7
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Xu S, Deng Y, Luo J, He E, Liu Y, Zhang K, Yang Y, Xu S, Sha L, Song Y, Xu Q, Cai X. High-Throughput PEDOT:PSS/PtNPs-Modified Microelectrode Array for Simultaneous Recording and Stimulation of Hippocampal Neuronal Networks in Gradual Learning Process. ACS APPLIED MATERIALS & INTERFACES 2022; 14:15736-15746. [PMID: 35294190 DOI: 10.1021/acsami.1c23170] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
When it comes to mechanisms of brain functions such as learning and memory mediated by neural networks, existing multichannel electrophysiological detection and regulation technology at the cellular level does not suffice. To address this challenge, a 128-channel microelectrode array (MEA) was fabricated for electrical stimulation (ES) training and electrophysiological recording of the hippocampal neurons in vitro. The PEDOT:PSS/PtNPs-coated microelectrodes dramatically promote the recording and electrical stimulation performance. The MEA exhibited low impedance (10.94 ± 0.49 kohm), small phase delay (-12.54 ± 0.51°), high charge storage capacity (14.84 ± 2.72 mC/cm2), and high maximum safe injection charge density (4.37 ± 0.22 mC/cm2), meeting the specific requirements for training neural networks in vitro. A series of ESs at various frequencies was applied to the neuronal cultures in vitro, seeking the optimum training mode that enables the neuron to display the most obvious plasticity, and 1 Hz ES was determined. The network learning process, including three consecutive trainings, affected the original random spontaneous activity. Along with that, the firing pattern gradually changed to burst and the correlation and synchrony of the neuronal activity in the network have progressively improved, increasing by 314% and 240%, respectively. The neurons remembered these changes for at least 4 h. Collectively, ES activates the learning and memory functions of neurons, which is manifested in transformations in the discharge pattern and the improvement of network correlation and synchrony. This study offers a high-performance MEA revealing the underlying learning and memory functions of the brain and therefore serves as a useful tool for the development of brain functions in the future.
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Affiliation(s)
- Shihong Xu
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Deng
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, China
| | - Jinping Luo
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Enhui He
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaoyao Liu
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kui Zhang
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Yang
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shengwei Xu
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Longze Sha
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, China
- Neuroscience Center, Chinese Academy of Medical Sciences, Beijing 100005, China
| | - Yilin Song
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi Xu
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, China
- Neuroscience Center, Chinese Academy of Medical Sciences, Beijing 100005, China
| | - Xinxia Cai
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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8
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Spira ME, Erez H, Sharon A. Assessing the Feasibility of Developing in vivo Neuroprobes for Parallel Intracellular Recording and Stimulation: A Perspective. Front Neurosci 2022; 15:807797. [PMID: 35145375 PMCID: PMC8821521 DOI: 10.3389/fnins.2021.807797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/16/2021] [Indexed: 11/29/2022] Open
Abstract
Developing novel neuroprobes that enable parallel multisite, long-term intracellular recording and stimulation of neurons in freely behaving animals is a neuroscientist's dream. When fulfilled, it is expected to significantly enhance brain research at fundamental mechanistic levels including that of subthreshold signaling and computations. Here we assess the feasibility of merging the advantages of in vitro vertical nanopillar technologies that support intracellular recordings with contemporary concepts of in vivo extracellular field potential recordings to generate the dream neuroprobes that read the entire electrophysiological signaling repertoire.
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Affiliation(s)
- Micha E. Spira
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hadas Erez
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Aviv Sharon
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
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9
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Lo CY, Wu Y, Awuyah E, Meli D, Nguyen DM, Wu R, Xu B, Strzalka J, Rivnay J, Martin DC, Kayser LV. Influence of the molecular weight and size distribution of PSS on mixed ionic-electronic transport in PEDOT:PSS. Polym Chem 2022; 13:2764-2775. [PMID: 36189107 PMCID: PMC9523623 DOI: 10.1039/d2py00271j] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The commercially available polyelectrolyte complex poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is ubiquitous in organic and hybrid electronics. As such, it has often been used as a benchmark material for fundamental studies and the development of new electronic devices. Yet, most studies on PEDOT:PSS have focused on its electronic conductivity in dry environments, with less consideration given to its ion transport, coupled ionic-electronic transport, and charge storage properties in aqueous environments. These properties are essential for applications in bioelectronics (sensors, actuators), charge storage devices, and electrochromic displays. Importantly, past studies on mixed ionic-electronic transport in PEDOT:PSS neglected to consider how the molecular structure of PSS affects mixed ionic-electronic transport. Herein, we therefore investigated the effect of the molecular weight and size distribution of PSS on the electronic properties and morphology of PEDOT:PSS both in dry and aqueous environments, and overall performance in organic electrochemical transistors (OECTs). Using reversible addition-fragmentation chain transfer (RAFT) polymerization with two different chain transfer agents, six PSS samples with monomodal, narrow (Đ = 1.1) and broad (Đ = 1.7) size distributions and varying molecular weights were synthesized and used as matrices for PEDOT. We found that using higher molecular weight of PSS (M n = 145 kg mol-1) and broad dispersity led to OECTs with the highest transconductance (up to 16 mS) and [μC * ] values (~140 F·cm-1V-1s-1) in PEDOT:PSS, despite having a lower volumetric capacitance (C * = 35 ± 4 F cm-3). The differences were best explained by studying the microstructure of the films by atomic force microscopy (AFM). We found that heterogeneities in the PEDOT:PSS films (interconnected and large PEDOT- and PSS-rich domains) obtained from high molecular weight and high dispersity PSS led to higher charge mobility (μ OECT ~ 4 cm2V-1s-1) and hence transconductance. These studies highlight the importance of considering molecular weight and size distribution in organic mixed ionic-electronic conductor, and could pave the way to designing high performance organic electronics for biological interfaces.
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Affiliation(s)
- Chun-Yuan Lo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716
| | - Yuhang Wu
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716
| | - Elorm Awuyah
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716
| | - Dilara Meli
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208
| | - Dan My Nguyen
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716
| | - Ruiheng Wu
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Bohan Xu
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208
| | - Joseph Strzalka
- X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois 60611
| | - Jonathan Rivnay
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208
- Simpson Querrey Institute, Northwestern University, Chicago, Illinois 60611
| | - David C Martin
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, 19716
| | - Laure V Kayser
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716
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10
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Pitsalidis C, Pappa AM, Boys AJ, Fu Y, Moysidou CM, van Niekerk D, Saez J, Savva A, Iandolo D, Owens RM. Organic Bioelectronics for In Vitro Systems. Chem Rev 2021; 122:4700-4790. [PMID: 34910876 DOI: 10.1021/acs.chemrev.1c00539] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bioelectronics have made strides in improving clinical diagnostics and precision medicine. The potential of bioelectronics for bidirectional interfacing with biology through continuous, label-free monitoring on one side and precise control of biological activity on the other has extended their application scope to in vitro systems. The advent of microfluidics and the considerable advances in reliability and complexity of in vitro models promise to eventually significantly reduce or replace animal studies, currently the gold standard in drug discovery and toxicology testing. Bioelectronics are anticipated to play a major role in this transition offering a much needed technology to push forward the drug discovery paradigm. Organic electronic materials, notably conjugated polymers, having demonstrated technological maturity in fields such as solar cells and light emitting diodes given their outstanding characteristics and versatility in processing, are the obvious route forward for bioelectronics due to their biomimetic nature, among other merits. This review highlights the advances in conjugated polymers for interfacing with biological tissue in vitro, aiming ultimately to develop next generation in vitro systems. We showcase in vitro interfacing across multiple length scales, involving biological models of varying complexity, from cell components to complex 3D cell cultures. The state of the art, the possibilities, and the challenges of conjugated polymers toward clinical translation of in vitro systems are also discussed throughout.
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Affiliation(s)
- Charalampos Pitsalidis
- Department of Physics, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi 127788, UAE.,Department of Chemical Engineering and Biotechnology, University of Cambridge Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| | - Anna-Maria Pappa
- Department of Biomedical Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi 127788, UAE
| | - Alexander J Boys
- Department of Chemical Engineering and Biotechnology, University of Cambridge Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| | - Ying Fu
- Department of Chemical Engineering and Biotechnology, University of Cambridge Philippa Fawcett Drive, Cambridge CB3 0AS, U.K.,Department of Pure and Applied Chemistry, Technology and Innovation Centre, University of Strathclyde, Glasgow G1 1RD, U.K
| | - Chrysanthi-Maria Moysidou
- Department of Chemical Engineering and Biotechnology, University of Cambridge Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| | - Douglas van Niekerk
- Department of Chemical Engineering and Biotechnology, University of Cambridge Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| | - Janire Saez
- Department of Chemical Engineering and Biotechnology, University of Cambridge Philippa Fawcett Drive, Cambridge CB3 0AS, U.K.,Microfluidics Cluster UPV/EHU, BIOMICs Microfluidics Group, Lascaray Research Center, University of the Basque Country UPV/EHU, Avenida Miguel de Unamuno, 3, 01006 Vitoria-Gasteiz, Spain.,Ikerbasque, Basque Foundation for Science, E-48011 Bilbao, Spain
| | - Achilleas Savva
- Department of Chemical Engineering and Biotechnology, University of Cambridge Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| | - Donata Iandolo
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, 42023 Saint-Étienne, France
| | - Róisín M Owens
- Department of Chemical Engineering and Biotechnology, University of Cambridge Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
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11
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Sharon A, Shmoel N, Erez H, Jankowski MM, Friedmann Y, Spira ME. Ultrastructural Analysis of Neuroimplant-Parenchyma Interfaces Uncover Remarkable Neuroregeneration Along-With Barriers That Limit the Implant Electrophysiological Functions. Front Neurosci 2021; 15:764448. [PMID: 34880722 PMCID: PMC8645653 DOI: 10.3389/fnins.2021.764448] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/21/2021] [Indexed: 12/13/2022] Open
Abstract
Despite increasing use of in vivo multielectrode array (MEA) implants for basic research and medical applications, the critical structural interfaces formed between the implants and the brain parenchyma, remain elusive. Prevailing view assumes that formation of multicellular inflammatory encapsulating-scar around the implants [the foreign body response (FBR)] degrades the implant electrophysiological functions. Using gold mushroom shaped microelectrodes (gMμEs) based perforated polyimide MEA platforms (PPMPs) that in contrast to standard probes can be thin sectioned along with the interfacing parenchyma; we examined here for the first time the interfaces formed between brains parenchyma and implanted 3D vertical microelectrode platforms at the ultrastructural level. Our study demonstrates remarkable regenerative processes including neuritogenesis, axon myelination, synapse formation and capillaries regrowth in contact and around the implant. In parallel, we document that individual microglia adhere tightly and engulf the gMμEs. Modeling of the formed microglia-electrode junctions suggest that this configuration suffice to account for the low and deteriorating recording qualities of in vivo MEA implants. These observations help define the anticipated hurdles to adapting the advantageous 3D in vitro vertical-electrode technologies to in vivo settings, and suggest that improving the recording qualities and durability of planar or 3D in vivo electrode implants will require developing approaches to eliminate the insulating microglia junctions.
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Affiliation(s)
- Aviv Sharon
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nava Shmoel
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hadas Erez
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maciej M. Jankowski
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yael Friedmann
- Bio-Imaging Unit, The Alexander Silberman Institute of Life Science the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Micha E. Spira
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
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12
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Vėbraitė I, David-Pur M, Rand D, Głowacki ED, Hanein Y. Electrophysiological investigation of intact retina with soft printed organic neural interface. J Neural Eng 2021; 18. [PMID: 34736225 DOI: 10.1088/1741-2552/ac36ab] [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: 07/25/2021] [Accepted: 11/04/2021] [Indexed: 12/26/2022]
Abstract
Objective.Understanding how the retina converts a natural image or an electrically stimulated one into neural firing patterns is the focus of on-going research activities.Ex vivo, the retina can be readily investigated using multi electrode arrays (MEAs). However, MEA recording and stimulation from an intact retina (in the eye) has been so far insufficient.Approach.In the present study, we report new soft carbon electrode arrays suitable for recording and stimulating neural activity in an intact retina. Screen-printing of carbon ink on 20µm polyurethane (PU) film was used to realize electrode arrays with electrodes as small as 40µm in diameter. Passivation was achieved with a holey membrane, realized using laser drilling in a thin (50µm) PU film. Plasma polymerized 3.4-ethylenedioxythiophene was used to coat the electrode array to improve the electrode specific capacitance. Chick retinas, embryonic stage day 13, both explanted and intact inside an enucleated eye, were used.Main results.A novel fabrication process based on printed carbon electrodes was developed and yielded high capacitance electrodes on a soft substrate.Ex vivoelectrical recording of retina activity with carbon electrodes is demonstrated. With the addition of organic photo-capacitors, simultaneous photo-electrical stimulation and electrical recording was achieved. Finally, electrical activity recordings from an intact chick retina (inside enucleated eyes) were demonstrated. Both photosensitive retinal ganglion cell responses and spontaneous retina waves were recorded and their features analyzed.Significance.Results of this study demonstrated soft electrode arrays with unique properties, suitable for simultaneous recording and photo-electrical stimulation of the retina at high fidelity. This novel electrode technology opens up new frontiers in the study of neural tissuein vivo.
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Affiliation(s)
- Ieva Vėbraitė
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, 699780, Israel
| | - Moshe David-Pur
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, 699780, Israel
| | - David Rand
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, 699780, Israel
| | - Eric Daniel Głowacki
- Central European Institute of Technology, Brno University of Technology, Brno, 61200, Czech Republic
| | - Yael Hanein
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, 699780, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 699780, Israel
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13
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Guimerà-Brunet A, Masvidal-Codina E, Cisneros-Fernández J, Serra-Graells F, Garrido JA. Novel transducers for high-channel-count neuroelectronic recording interfaces. Curr Opin Biotechnol 2021; 72:39-47. [PMID: 34695765 DOI: 10.1016/j.copbio.2021.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 01/12/2023]
Abstract
Neuroelectronic interfaces with the nervous system are an essential technology in state-of-the-art neuroscience research aiming to uncover the fundamental working mechanisms of the brain. Progress towards increased spatio-temporal resolution has been tightly linked to the advance of microelectronics technology and novel materials. Translation of these technologies to neuroscience has resulted in multichannel neural probes and acquisition systems enabling the recording of brain signals using thousands of channels. This review provides an overview of state-of-the-art neuroelectronic technologies, with emphasis on recording site architectures which enable the implementation of addressable arrays for high-channel-count neural interfaces. In this field, active transduction mechanisms are gaining importance fueled by novel materials, as they facilitate the implementation of high density addressable arrays.
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Affiliation(s)
- Anton Guimerà-Brunet
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra, Spain; Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Eduard Masvidal-Codina
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra, Spain; Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | | | - Francesc Serra-Graells
- Institut de Microelectrònica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Bellaterra, Spain; Universitat Autònoma de Barcelona, Spain
| | - Jose A Garrido
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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14
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Functionalization Strategies of PEDOT and PEDOT:PSS Films for Organic Bioelectronics Applications. CHEMOSENSORS 2021. [DOI: 10.3390/chemosensors9080212] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Organic bioelectronics involves the connection of organic semiconductors with living organisms, organs, tissues, cells, membranes, proteins, and even small molecules. In recent years, this field has received great interest due to the development of all kinds of devices architectures, enabling the detection of several relevant biomarkers, the stimulation and sensing of cells and tissues, and the recording of electrophysiological signals, among others. In this review, we discuss recent functionalization approaches for PEDOT and PEDOT:PSS films with the aim of integrating biomolecules for the fabrication of bioelectronics platforms. As the choice of the strategy is determined by the conducting polymer synthesis method, initially PEDOT and PEDOT:PSS films preparation methods are presented. Later, a wide variety of PEDOT functionalization approaches are discussed, together with bioconjugation techniques to develop efficient organic-biological interfaces. Finally, and by making use of these approaches, the fabrication of different platforms towards organic bioelectronics devices is reviewed.
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15
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Lee MJ, Zeck G. Electrical Imaging of Light-Induced Signals Across and Within Retinal Layers. Front Neurosci 2020; 14:563964. [PMID: 33328846 PMCID: PMC7717958 DOI: 10.3389/fnins.2020.563964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 10/12/2020] [Indexed: 11/20/2022] Open
Abstract
The mammalian retina processes sensory signals through two major pathways: a vertical excitatory pathway, which involves photoreceptors, bipolar cells, and ganglion cells, and a horizontal inhibitory pathway, which involves horizontal cells, and amacrine cells. This concept explains the generation of an excitatory center—inhibitory surround sensory receptive fields—but fails to explain the modulation of the retinal output by stimuli outside the receptive field. Electrical imaging of light-induced signal propagation at high spatial and temporal resolution across and within different retinal layers might reveal mechanisms and circuits involved in the remote modulation of the retinal output. Here we took advantage of a high-density complementary metal oxide semiconductor-based microelectrode array and investigated the light-induced propagation of local field potentials (LFPs) in vertical mouse retina slices. Surprisingly, the LFP propagation within the different retinal layers depends on stimulus duration and stimulus background. Application of the same spatially restricted light stimuli to flat-mounted retina induced ganglion cell activity at remote distances from the stimulus center. This effect disappeared if a global background was provided or if gap junctions were blocked. We hereby present a neurotechnological approach and demonstrated its application, in which electrical imaging evaluates stimulus-dependent signal processing across different neural layers.
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Affiliation(s)
- Meng-Jung Lee
- Neurophysics, NMI Natural and Medical Sciences Institute at the University Tübingen, Reutlingen, Germany.,Graduate School of Neural Information Processing, International Max Planck Research School, Tübingen, Germany
| | - Günther Zeck
- Neurophysics, NMI Natural and Medical Sciences Institute at the University Tübingen, Reutlingen, Germany
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16
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Mierzejewski M, Steins H, Kshirsagar P, Jones PD. The noise and impedance of microelectrodes. J Neural Eng 2020; 17:052001. [PMID: 33055360 DOI: 10.1088/1741-2552/abb3b4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE While the positive correlation between impedance and noise of microelectrodes is well known, their quantitative relationship is too rarely described. Knowledge of this relationship provides useful information for both microsystems engineers and electrophysiologists. APPROACH We discuss the physical basis of noise in recordings with microelectrodes, and compare measurements of impedance spectra to noise of microelectrodes. MAIN RESULTS Microelectrode recordings intrinsically include thermal noise, [Formula: see text], with the real component of impedance integrated over the recording frequency band. Impedance spectroscopy allows the quantitative prediction of thermal noise. Optimization of microelectrode noise should also consider the contribution of amplifier noise. These measures enable a quantitative evaluation of microelectrodes' recording quality which is more informative than common but limited comparisons based on the impedance magnitude at 1 kHz. SIGNIFICANCE Improved understanding of the origin of microelectrode noise will support efforts to produce smaller yet low noise microelectrodes, capable of recording from higher numbers of neurons. This tutorial is relevant for single microelectrodes, tetrodes, neural probes and microelectrode arrays, whether used in vitro or in vivo.
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Affiliation(s)
- Michael Mierzejewski
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
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17
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Dollt M, Reh M, Metzger M, Heusel G, Kriebel M, Bucher V, Zeck G. Low-Temperature Atomic Layer Deposited Oxide on Titanium Nitride Electrodes Enables Culture and Physiological Recording of Electrogenic Cells. Front Neurosci 2020; 14:552876. [PMID: 33071735 PMCID: PMC7530285 DOI: 10.3389/fnins.2020.552876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 08/13/2020] [Indexed: 12/27/2022] Open
Abstract
The performance of electrode arrays insulated by low-temperature atomic layer deposited (ALD) titanium dioxide (TiO2) or hafnium dioxide (HfO2) for culture of electrogenic cells and for recording of extracellular action potentials is investigated. If successful, such insulation may be considered to increase the stability of future neural implants. Here, insulation of titanium nitride electrodes of microelectrode arrays (MEAs) was performed using ALD of nanometer-sized TiO2 or hafnium oxide at low temperatures (100-200°C). The electrode properties, impedance, and leakage current were measured and compared. Although electrode insulation using ALD oxides increased the electrode impedance, it did not prevent stable, physiological recordings of electrical activity from electrogenic cells (cardiomyocytes and neurons). The insulation quality, estimated from leakage current measurements, was less than 100 nA/cm2 in a range of 3 V. Cardiomyocytes were successfully cultured and recorded after 5 days on the insulated MEAs with signal shapes similar to the recordings obtained using uncoated electrodes. Light-induced electrical activity of retinal ganglion cells was recorded using a complementary metal-oxide semiconductor-based MEA insulated with HfO2 without driving the recording electrode into saturation. The presented results demonstrate that low-temperature ALD-deposited TiO2 and hafnium oxide are biocompatible and biostable and enable physiological recordings. Our results indicate that nanometer-sized ALD insulation can be used to protect electrodes for long-term biological applications.
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Affiliation(s)
- Michele Dollt
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Miriam Reh
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- Graduate School of Neural Information Processing/International Max Planck Research School, University of Tübingen, Reutlingen, Germany
| | - Michael Metzger
- Mechanical and Medical Engineering, Hochschule Furtwangen University, Villingen-Schwenningen, Germany
| | - Gerhard Heusel
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Martin Kriebel
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Volker Bucher
- Mechanical and Medical Engineering, Hochschule Furtwangen University, Villingen-Schwenningen, Germany
| | - Günther Zeck
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
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