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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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Huang SH, Shmoel N, Jankowski MM, Erez H, Sharon A, Abu-Salah W, Nelken I, Weiss A, Spira ME. Immunohistological and Ultrastructural Study of the Inflammatory Response to Perforated Polyimide Cortical Implants: Mechanisms Underlying Deterioration of Electrophysiological Recording Quality. Front Neurosci 2020; 14:926. [PMID: 32982683 PMCID: PMC7489236 DOI: 10.3389/fnins.2020.00926] [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: 05/26/2020] [Accepted: 08/11/2020] [Indexed: 12/12/2022] Open
Abstract
The deterioration of field potential (FP) recording quality and yield by in vivo multielectrode arrays (MEA) within days to weeks of implantation severely limits progress in basic and applied brain research. The prevailing hypothesis is that implantation of MEA platforms initiate and perpetuate inflammatory processes which culminate in the formation of scar tissue (the foreign body response, FBR) around the implant. The FBR leads to progressive degradation of the recording qualities by displacing neurons away from the electrode surfaces, increasing the resistance between neurons (current source) and the sensing pads and by reducing the neurons’ excitable membrane properties and functional synaptic connectivity through the release of pro-inflammatory cytokines. Meticulous attempts to causally relate the cellular composition, cell density, and electrical properties of the FBR have failed to unequivocally correlate the deterioration of recording quality with the histological severity of the FBR. Based on confocal and electron microscope analysis of thin sections of polyimide based MEA implants along with the surrounding brain tissue at different points in time after implantation, we propose that abrupt FP amplitude attenuation occurs at the implant/brain-parenchyma junction as a result of high seal resistance insulation formed by adhering microglia to the implant surfaces. In contrast to the prevailing hypothesis, that FP decrease occurs across the encapsulating scar of the implanted MEA, this mechanism potentially explains why no correlations have been found between the dimensions and density of the FBR and the recording quality. Recognizing that the seal resistance formed by adhering-microglia to the implant constitutes a downstream element undermining extracellular FP recordings, suggests that approaches to mitigate the formation of the insulating glial could lead to improved recording quality and yield.
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Affiliation(s)
- Shun-Ho Huang
- 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
| | - Nava Shmoel
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel.,The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel.,The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maciej M Jankowski
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel.,The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel.,Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - 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
| | - Wesal Abu-Salah
- 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
| | - Israel Nelken
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel.,Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Aryeh Weiss
- Faculty of Engineering, Bar-Ilan University, Ramat Gan, 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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3
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Thakore V, Molnar P, Hickman JJ. An optimization-based study of equivalent circuit models for representing recordings at the neuron-electrode interface. IEEE Trans Biomed Eng 2012; 59:2338-47. [PMID: 22695342 DOI: 10.1109/tbme.2012.2203820] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Extracellular neuroelectronic interfacing is an emerging field with important applications in the fields of neural prosthetics, biological computation, and biosensors. Traditionally, neuron-electrode interfaces have been modeled as linear point or area contact equivalent circuits but it is now being increasingly realized that such models cannot explain the shapes and magnitudes of the observed extracellular signals. Here, results were compared and contrasted from an unprecedented optimization-based study of the point contact models for an extracellular "on-cell" neuron-patch electrode and a planar neuron-microelectrode interface. Concurrent electrophysiological recordings from a single neuron simultaneously interfaced to three distinct electrodes (intracellular, "on-cell" patch, and planar microelectrode) allowed novel insights into the mechanism of signal transduction at the neuron-electrode interface. After a systematic isolation of the nonlinear neuronal contribution to the extracellular signal, a consistent underestimation of the simulated suprathreshold extracellular signals compared to the experimentally recorded signals was observed. This conclusively demonstrated that the dynamics of the interfacial medium contribute nonlinearly to the process of signal transduction at the neuron-electrode interface. Further, an examination of the optimized model parameters for the experimental extracellular recordings from sub- and suprathreshold stimulations of the neuron-electrode junctions revealed that ionic transport at the "on-cell" neuron-patch electrode is dominated by diffusion whereas at the neuron-microelectrode interface the electric double layer (EDL) effects dominate. Based on this study, the limitations of the equivalent circuit models in their failure to account for the nonlinear EDL and ionic electrodiffusion effects occurring during signal transduction at the neuron-electrode interfaces are discussed.
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Affiliation(s)
- V Thakore
- Department of Physics and the Nano Science TechnologyCenter, University of Central Florida, Orlando, FL 32826, USA.
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Boinagrov D, Loudin J, Palanker D. Strength-duration relationship for extracellular neural stimulation: numerical and analytical models. J Neurophysiol 2010; 104:2236-48. [PMID: 20702740 DOI: 10.1152/jn.00343.2010] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The strength-duration relationship for extracellular stimulation is often assumed to be similar to the classical intracellular stimulation model, with a slope asymptotically approaching 1/τ at pulse durations shorter than chronaxy. We modeled extracellular neural stimulation numerically and analytically for several cell shapes and types of active membrane properties. The strength-duration relationship was found to differ significantly from classical intracellular models. At pulse durations between 4 μs and 5 ms stimulation is dominated by sodium channels, with a slope of -0.72 in log-log coordinates for the Hodgkin-Huxley ion channel model. At shorter durations potassium channels dominate and slope decreases to -0.13. Therefore the charge per phase is decreasing with decreasing stimulus duration. With pulses shorter than cell polarization time (∼0.1-1 μs), stimulation is dominated by polarization dynamics with a classical -1 slope and the charge per phase becomes constant. It is demonstrated that extracellular stimulation can have not only lower but also upper thresholds and may be impossible below certain pulse durations. In some regimes the extracellular current can hyperpolarize cells, suppressing rather than stimulating spiking behavior. Thresholds for burst stimuli can be either higher or lower than that of a single pulse, depending on pulse duration. The modeled thresholds were found to be comparable to published experimental data. Electroporation thresholds, which limit the range of safe stimulation, were found to exceed stimulation thresholds by about two orders of magnitude. These results provide a biophysical basis for understanding stimulation dynamics and guidance for optimizing the neural stimulation efficacy and safety.
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Affiliation(s)
- David Boinagrov
- Stanford University, Hansen Experimental Physics Laboratory, 452 Lomita Mall, Stanford, CA 94305, USA.
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5
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Neural stem cells from human cord blood on bioengineered surfaces—Novel approach to multiparameter bio-tests. Toxicology 2010; 270:35-42. [DOI: 10.1016/j.tox.2009.06.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2009] [Accepted: 06/04/2009] [Indexed: 11/23/2022]
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6
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Jurga M, Lipkowski AW, Lukomska B, Buzanska L, Kurzepa K, Sobanski T, Habich A, Coecke S, Gajkowska B, Domanska-Janik K. Generation of functional neural artificial tissue from human umbilical cord blood stem cells. Tissue Eng Part C Methods 2009; 15:365-72. [PMID: 19719393 DOI: 10.1089/ten.tec.2008.0485] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Stem cell-based regenerative neurology is an emerging concept for treatment of diseases of central nervous system. Among variety of proposed procedures, one of the most promising is refilling of cystic cavities of injured brain parenchyma with artificial neural tissue. Recent studies revealed that after allogenic transplantation in rodents these tissue-engineered entities were shown efficient in repair of hypoxic/ischemic brain injury. Human umbilical cord blood (HUCB) was recognized to be an efficient and noncontroversial source of neural stem cells (NSC). The main purpose of this study was to generate HUCB-derived neural artificial tissue and investigate their functional properties. Neural organoids formed on human-originated biodegradable scaffolds within 3 weeks and resembled niche structure where immature stem cells (Oct4+ and Sox2+) and proliferating neuroblasts (Nestin+, GFAP+, and Ki67+) were present. Such aggregates were placed on multi-electrode chips and differentiated toward mature neurons (TUJ1+ and MAP2+). These three-dimensional aggregates in contrast to two-dimensional cultures formed functional circuits and generated spontaneous field/action potentials. Our results indicate that three-dimensional environment facilitates maturation of HUCB-derived NSC what should be considered regarding regenerative medicine application.
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Affiliation(s)
- Marcin Jurga
- Department of Neurorepair, Medical Research Institute, Polish Academy of Sciences, Warsaw 02-106, Poland.
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7
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Lin SP, Kyriakides TR, Chen JJJ. On-line observation of cell growth in a three-dimensional matrix on surface-modified microelectrode arrays. Biomaterials 2009; 30:3110-7. [PMID: 19344948 DOI: 10.1016/j.biomaterials.2009.03.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Accepted: 03/08/2009] [Indexed: 11/24/2022]
Abstract
Despite many successful applications of microelectrode arrays (MEAs), typical two-dimensional in-vitro cultures do not project the full scale of the cell growth environment in the three-dimensional (3D) in-vivo setting. This study aims to on-line monitor in-vitro cell growth in a 3D matrix on the surface-modified MEAs with a dynamic perfusion culture system. A 3D matrix consisting of poly(ethylene glycol) hydrogel supplemented with poly-D-lysine was subsequently synthesized in situ on the self-assembled monolayer modified MEAs. FTIR spectrum analysis revealed a peak at 2100 cm(-1) due to the degradation of the structure of the 3D matrix. After 2 wks, microscopic examination revealed that the non-degraded area was around 1500 microm(2) and provided enough space for cell growth. Fluorescence microscopy revealed that the degraded 3D matrix was non-cytotoxic allowing the growth of NIH3T3 fibroblasts and cortical neurons in vitro. Time-course changes of total impedance including resistance and reactance were recorded for 8 days to evaluate the cell growth in the 3D matrix on the MEA. A consistent trend reflecting changes of reactance and total impedance was observed. These in-vitro assays demonstrate that our 3D matrix can construct a biomimetic system for cell growth and analysis of cell surface interactions.
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Affiliation(s)
- Shu-Ping Lin
- Institute of Biomedical Engineering, National Cheng Kung University, 1 Ta-Hsueh Rd., Tainan 701, Taiwan, ROC
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8
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Jurga M, Lipkowski AW, Lukomska B, Buzanska L, Kurzepa K, Sobanski T, Habich A, Coecke S, Gajkowska B, Domanska-Janik K. Generation of Functional Neural Artificial Tissue from Human Umbilical Cord Blood Stem Cells. Tissue Eng Part A 2009. [DOI: 10.1089/ten.tea.2008.0485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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9
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Thakore V, Behal A, Molnar P, Leistritz DC, Hickman JJ. Nanoscale Nonlinear dynamic characterization of the neuron-electrode junction. JOURNAL OF COMPUTATIONAL AND THEORETICAL NANOSCIENCE 2008; 5:2164-2169. [PMID: 20204183 PMCID: PMC2831233 DOI: 10.1166/jctn.2008.1114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Extracellular recordings from neurons using microelectrode and field effect transistor arrays suffer from many problems including low signal to noise ratio, signal attenuation due to counter-ion diffusion from the bulk extracellular medium and a modification of the shape of the cell-generated potentials due to the presence of a highly dispersive dielectric medium in the cell-electrode cleft. Attempts to date to study the neuron-electrode interface have focused on point or area contact linear-equivalent-circuit models. We present here the results obtained from a 'data-true' nonlinear dynamic characterization of the neuron-electrode junction using Volterra-Wiener modeling. For the characterization, NG108-15 cells were cultured on microelectrode arrays and stimulated with broadband Gaussian white noise under voltage clamp mode. A Volterra-Wiener model was then estimated using the input signal and the extracellular signal recorded on the microelectrode. The existence of the second order Wiener kernel confirmed that the recorded extracellular signal had a nonlinear component. The verification of the estimated model was carried out by employing the intracellular action potential as an input to the Volterra-Wiener model and comparing the predicted extracellular response with the corresponding extracellular signal recorded on the microelectrode. We believe that a 'data-true' Volterra-Wiener model of the neuron-electrode junction shall not only facilitate a direct insight into the physicochemical processes taking place at the interface during signal transduction but will also allow one to evolve strategies for engineering the neuron-electrode interface using surface chemical modification of the microelectrodes.
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Affiliation(s)
- V Thakore
- Nanoscience Technology Center, University of Central Florida
- Department of Physics, University of Central Florida
| | - A Behal
- Nanoscience Technology Center, University of Central Florida
- Department of Electrical and Computer Engineering, University of Central Florida
| | - P Molnar
- Nanoscience Technology Center, University of Central Florida
| | - D C Leistritz
- Nanoscience Technology Center, University of Central Florida
| | - J J Hickman
- Nanoscience Technology Center, University of Central Florida
- Department of Physics, University of Central Florida
- Department of Electrical and Computer Engineering, University of Central Florida
- Department of Chemistry, University of Central Florida
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10
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Lin SP, Chen JJJ, Liao JD, Tzeng SF. Characterization of surface modification on microelectrode arrays for in vitro cell culture. Biomed Microdevices 2008; 10:99-111. [PMID: 17674208 DOI: 10.1007/s10544-007-9114-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study aims to investigate surface-modified microelectrodes on the microelectrode arrays (MEAs) for neuronal interfaces with in vitro cell culture. The polyimide (PI) MEA was fabricated by using micro-electro-mechanical systems (MEMS) techniques. Self-assembled monolayers (SAMs) of 11-mercaptoundecanoic acid (MUA) were utilized to modify the microelectrode surface of the MEA. The SAMs' modified surface of microelectrodes offered a reliable interface to immobilize biological ligands through covalent bonding. To increase biocompatibility, the poly-D-lysine (PDL) was immobilized on the SAMs' modified microelectrodes. Several analytical techniques were used to define the physical structure and functional groups of surface-modified gold microelectrodes on the MEA. Spectra of the Fourier transform infrared reflection (FTIR) were applied to characterize the molecular structure of MUA-SAMs and PDL on the microelectrodes. The spectra, two peaks of amide I (at 1,613 cm(-1)) and amide II (at 1,548 cm(-1)), revealed that covalent amide bonding existed in PDL-MUA-SAMs modified surfaces. The thickness and formation of the MUA and PDL were also observed and quantified by using an atomic force microscope (AFM). The impedance measurement of PDL-MUA-SAMs modified MEA only increased slightly to an average of 524.6 +/- 55.8 kOmega from 352.9 +/- 34.4 kOmega of bare gold microelectrode (p < 0.05, N = 20). In addition, the time-course changes of total impedance resulting from cell sealing resistance and gap reactance were recorded for 7 days for inferring the growth of cell lines on the electrode contact of modified MEA. The experiment of 3T3 fibroblasts, PC12 cells, primary glial cells, and primary cortical neurons cultured on the modified MEAs displayed a good adhesion rate. These biocompatibility assays demonstrated that the neuronal cells are able to grow in a proximity to PDL-MUA-SAMs modified microelectrodes of the MEAs for effective electrophysiological stimulation/sensing schemes and for future implantation purposes.
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Affiliation(s)
- Shu-Ping Lin
- Institute of Biomedical Engineering, National Cheng Kung University, No. 1 Ta-Hsueh Road, Tainan, Taiwan, Republic of China
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Rutten WLC, Ruardij TG, Marani E, Roelofsen BH. Neural networks on chemically patterned electrode arrays: towards a cultured probe. ACTA NEUROCHIRURGICA. SUPPLEMENT 2007; 97:547-54. [PMID: 17691346 DOI: 10.1007/978-3-211-33081-4_63] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
One type of future, improved neural interfaces is the 'cultured probe'. It is a hybrid type of neural information transducer or prosthesis, for stimulation and/or recording of neural activity. It would consist of a micro-electrode array (MEA) on a planar substrate, each electrode being covered and surrounded by a local circularly confined network ('island') of cultured neurons. The main purpose of the local networks is that they act as bio-friendly intermediates for collateral sprouts from the in vivo system, thus allowing for an effective and selective neuron electrode interface. As a secondary purpose, one may envisage future information processing applications of these intermediary networks. In this chapter, first, progress is shown on how substrates can be chemically modified to confine developing networks, cultured from dissociated rat cortex cells, to 'islands' surrounding an electrode site. Additional coating of neurophobic, polyimide coated substrate by tri-block-copolymer coating enhances neurophilic-neurophobic adhesion contrast. Secondly, results are given on neuronal activity in patterned, unconnected and connected, circular 'island' networks. For connected islands, the larger the island diameter (50, 100 or 150 microm), the more spontaneous activity is seen. Also, activity may show a very high degree of synchronization between two islands. For unconnected islands, activity may start at 22 days in vitro (DIV), which is two weeks later than in unpatterned networks.
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Affiliation(s)
- W L C Rutten
- Biomedical Signals and Systems Department, Faculty of Electrical Engineering, Mathematics and Computer Science, Institute for Biomedical Technology, University of Twente, Enschede, The Netherlands.
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Hafizovic S, Heer F, Ugniwenko T, Frey U, Blau A, Ziegler C, Hierlemann A. A CMOS-based microelectrode array for interaction with neuronal cultures. J Neurosci Methods 2007; 164:93-106. [PMID: 17540452 DOI: 10.1016/j.jneumeth.2007.04.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2006] [Revised: 04/02/2007] [Accepted: 04/06/2007] [Indexed: 11/27/2022]
Abstract
We report on the system integration of a CMOS chip that is capable of bidirectionally communicating (stimulation and recording) with electrogenic cells such as neurons or cardiomyocytes and that is targeted at investigating electrical signal propagation within cellular networks in vitro. The overall system consists of three major subunits: first, the core component is a 6.5 mm x 6.5 mm CMOS chip, on top of which the cells are cultured. It features 128 bidirectional electrodes, each equipped with dedicated analog filters and amplification stages and a stimulation buffer. The electrodes are sampled at 20 kHz with 8-bit resolution. The measured input-referred circuitry noise is 5.9 microV root mean square (10 Hz to 100 kHz), which allows to reliably detect the cell signals ranging from 1 mVpp down to 40 microVpp. Additionally, temperature sensors, a digital-to-analog converter for stimulation, and a digital interface for data transmission are integrated. Second, there is a reconfigurable logic device, which provides chip control, event detection, data buffering and an USB interface, capable of processing the 2.56 million samples per second. The third element includes software that is running on a standard PC performing data capturing, processing, and visualization. Experiments involving the stimulation of neurons with two different spatio-temporal patterns and the recording of the triggered spiking activity have been carried out. The response patterns have been successfully classified (83% correct) with respect to the different stimulation patterns. The advantages over current microelectrode arrays, as has been demonstrated in the experiments, include the capability to stimulate (voltage stimulation, 8 bit, 60 kHz) spatio-temporal patterns on arbitrary sets of electrodes and the fast stimulation reset mechanism that allows to record neuronal signals on a stimulating electrode 5 ms after stimulation (instantaneously on all other electrodes). Other advantages of the overall system include the small number of needed electrical connections due to the digital interface and the short latency time that allows to initiate a stimulation less than 2 ms after the detection of an action potential in closed-loop configurations.
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Affiliation(s)
- S Hafizovic
- Physical Electronics Laboratory, ETH Zurich, Wolfgang-Pauli Str. 16, 8093 Zurich, Switzerland.
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13
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Rutten WLC, Ruardij TG, Marani E, Roelofsen BH. Cultured neural networks: Optimization of patterned network adhesiveness and characterization of their neural activity. Appl Bionics Biomech 2006. [DOI: 10.1533/abbi.2004.0027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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14
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Stett A, Bucher V, Burkhardt C, Weber U, Nisch W. Patch-clamping of primary cardiac cells with micro-openings in polyimide films. Med Biol Eng Comput 2003; 41:233-40. [PMID: 12691447 DOI: 10.1007/bf02344895] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Patch-clamping is a powerful method for investigating the function and regulation of ionic channels. Currently, great efforts are being made to automate this method. As a step towards this goal, the feasibility of patch-clamping primary cells with a microscopic opening in a planar substrate was tested. Using standard microfabrication and ion beam technology, small-diameter openings (2 and 4 microm) were formed in polyimide films (thickness 6.5 microm). Single cells (sheep Purkinje heart cells, Chinese hamster ovary cells) in a suspension were positioned on top of the opening and sucked towards the opening to improve adhesion of the cell to the planar substrate, hence increasing the seal resistance. Voltage/current measurements yielded a median seal resistance of 1.3 Mohms with 4 microm openings (n=24) and 26.0 Mohms with 2 microm openings (n = 75), respectively. With 2 microm openings, successful loose-patch recordings of TTX-sensitive inward currents and action potentials in sheep Purkinje heart cells (n = 18) were made. In rare cases, gigaseals (n = 4) were also measured, and a whole-cell configuration (n = 1) could be established. It was concluded that the simple planar patch approach is suitable for automated loose-patch recordings from cells in suspension but will hardly be suitable for high-throughput whole-cell patch-clamping with high-resistance seals.
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Affiliation(s)
- A Stett
- NMI Natural & Medical Science Institute, Reutlingen, Germany.
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15
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Buitenweg JR, Rutten WLC, Marani E. Extracellular stimulation window explained by a geometry-based model of the neuron-electrode contact. IEEE Trans Biomed Eng 2002; 49:1591-9. [PMID: 12549741 DOI: 10.1109/tbme.2002.804504] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Extracellular stimulation of single cultured neurons which are completely sealing a microelectrode is usually performed using anodic or biphasic currents of at least 200 nA. However, recently obtained experimental data demonstrate the possibility to stimulate a neuron using cathodic current pulses with less amplitude. Also, a stimulation window is observed. These findings can be explained by a finite-element model which permits geometry-based electrical representation of the neuron-electrode interface and can be used to explore the required conditions for extracellular stimulation in detail. Modulation of the voltage sensitive channels in the sealing part of the membrane appears to be the key to successful cathodic stimulation. Furthermore, the upper limit of the stimulation window can be explained as a normal consequence of the neuronal membrane electrophysiology.
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Affiliation(s)
- Jan Reinoud Buitenweg
- Institute for Biomedical Technology, Signals and Systems Group, Faculty of Electrical Engineering, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
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