Liquid Crystal Elastomer-Based Microelectrode Array for In Vitro Neuronal Recordings

Polymer-based biomedical electronics provide a tunable platform to interact with nervous tissue both in vitro and in vivo. Ultimately, the ability to control functional properties of neural interfaces may provide important advantages to study the nervous system or to restore function in patients with neurodegenerative disorders. Liquid crystal elastomers (LCEs) are a class of smart materials that reversibly change shape when exposed to a variety of stimuli. Our interest in LCEs is based on leveraging this shape change to deploy electrode sites beyond the tissue regions exhibiting inflammation associated with chronic implantation. As a first step, we demonstrate that LCEs are cellular compatible materials that can be used as substrates for fabricating microelectrode arrays (MEAs) capable of recording single unit activity in vitro. Extracts from LCEs are non-cytotoxic (>70% normalized percent viability), as determined in accordance to ISO protocol 10993-5 using fibroblasts and primary murine cortical neurons. LCEs are also not functionally neurotoxic as determined by exposing cortical neurons cultured on conventional microelectrode arrays to LCE extract for 48 h. Microelectrode arrays fabricated on LCEs are stable, as determined by electrochemical impedance spectroscopy. Examination of the impedance and phase at 1 kHz, a frequency associated with single unit recording, showed results well within range of electrophysiological recordings over 30 days of monitoring in phosphate-buffered saline (PBS). Moreover, the LCE arrays are shown to support viable cortical neuronal cultures over 27 days in vitro and to enable recording of prominent extracellular biopotentials comparable to those achieved with conventional commercially-available microelectrode arrays.

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INITIAL SURGICAL EXPERIENCE WITH A DENSE CORTICAL MICROARRAY IN EPILEPTIC PATIENTS UNDERGOING CRANIOTOMY FOR SUBDURAL ELECTRODE IMPLANTATION

Neurosurgery ◽

10.1227/01.neu.0000337575.63861.10 ◽

2009 ◽

Vol 64 (3) ◽

pp. 540-545 ◽

Cited By ~ 37

Author(s):

Allen Waziri ◽

Catherine A. Schevon ◽

Joshua Cappell ◽

Ronald G. Emerson ◽

Guy M. McKhann ◽

...

Keyword(s):

Local Field ◽

Single Unit ◽

Microelectrode Array ◽

Tissue Injury ◽

Local Field Potentials ◽

Microelectrode Arrays ◽

Field Potentials ◽

Surgical Experience ◽

Electrode Implantation ◽

Subdural Electrode

Abstract OBJECTIVE Detailed investigations of cortical physiology require the ability to record brain electrical activity at a submillimeter scale. Standard intracranial electrodes result in significant averaging of potentials generated by large numbers of neurons. In contrast, microelectrode arrays allow for recording of local field potentials and single-unit activity. We describe our initial surgical experience with the NeuroPort microelectrode array (Cyberkinetics Neurotechnology Systems, Inc., Salt Lake City, UT) in a series of patients undergoing subdural electrode implantation for epilepsy monitoring. METHODS Seven patients were implanted with and underwent semichronic recording from the NeuroPort array during standard subdural electrode monitoring for epilepsy. The electrode was placed according to company specifications in putative noneloquent epileptogenic cortex. After the monitoring period, microelectrode arrays were removed during explantation of subdural electrodes and resection of epileptogenic tissue. RESULTS Successful implantation of the microelectrode array was achieved in all patients, with minor operative difficulties. Robust and durable local field potentials and single-unit recordings were obtained from all implanted individuals. Implantation times ranged from 3 to 28 days; histological analysis of implanted tissue demonstrated no significant tissue injury or inflammatory response. There were no neurological complications or infections associated with electrode implantation or prolonged monitoring. Two patients developed postresection issues with wound healing at the site of scalp egress, with 1 requiring operative wound revision. CONCLUSION Our experience demonstrates that semichronic microelectroencephalographic recording can be safely and effectively achieved using the NeuroPort microarray. Although significant tissue injury, infection, or cerebrospinal fluid leak was not encountered, the large profile of the connection pedestal resulted in suboptimal wound closure and healing in several patients. We predict that this problem will be easily addressed in second-generation devices.

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Versatile live-cell activity analysis platform for characterization of neuronal dynamics at single-cell and network level

Nature Communications ◽

10.1038/s41467-020-18620-4 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Xinyue Yuan ◽

Manuel Schröter ◽

Marie Engelene J. Obien ◽

Michele Fiscella ◽

Wei Gong ◽

...

Keyword(s):

Neuronal Networks ◽

Microelectrode Array ◽

Cell Activity ◽

Live Cell ◽

High Signal ◽

Neuronal Cultures ◽

Label Free ◽

Fluorescent Indicators ◽

Analysis Platform

AbstractChronic imaging of neuronal networks in vitro has provided fundamental insights into mechanisms underlying neuronal function. Current labeling and optical imaging methods, however, cannot be used for continuous and long-term recordings of the dynamics and evolution of neuronal networks, as fluorescent indicators can cause phototoxicity. Here, we introduce a versatile platform for label-free, comprehensive and detailed electrophysiological live-cell imaging of various neurogenic cells and tissues over extended time scales. We report on a dual-mode high-density microelectrode array, which can simultaneously record in (i) full-frame mode with 19,584 recording sites and (ii) high-signal-to-noise mode with 246 channels. We set out to demonstrate the capabilities of this platform with recordings from primary and iPSC-derived neuronal cultures and tissue preparations over several weeks, providing detailed morpho-electrical phenotypic parameters at subcellular, cellular and network level. Moreover, we develop reliable analysis tools, which drastically increase the throughput to infer axonal morphology and conduction speed.

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Extracellular single-unit recordings from peripheral nerve axons in vitro by a novel multichannel microelectrode array

Sensors and Actuators B Chemical ◽

10.1016/j.snb.2020.128111 ◽

2020 ◽

Vol 315 ◽

pp. 128111 ◽

Cited By ~ 2

Author(s):

Tiantian Guo ◽

Longtu Chen ◽

Khanh Tran ◽

Pejman Ghelich ◽

Yi-Syuan Guo ◽

...

Keyword(s):

Peripheral Nerve ◽

Single Unit ◽

Microelectrode Array ◽

Single Unit Recordings

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Optogenetic Modulation of Cortical Neurons Using Organic Light Emitting Diodes (OLEDs)

10.1101/669986 ◽

2019 ◽

Author(s):

Arati Sridharan ◽

Ankur Shah ◽

Swathy Sampath Kumar ◽

James Kyeh ◽

Joseph Smith ◽

...

Keyword(s):

Mouse Model ◽

Transgenic Mouse ◽

Cortical Neurons ◽

Microelectrode Array ◽

Light Emitting Diodes ◽

Green Light ◽

Transgenic Mouse Model ◽

Light Emitting

ABSTRACTObjectiveThere is a need for low power, scalable photoelectronic devices and systems for emerging optogenetic needs in neuromodulation. Conventional light emitting diodes (LEDs) are constrained by power and lead-counts necessary for scalability. Organic LEDs (OLEDs) offer an exciting approach to decrease power and lead-counts while achieving high channel counts on thin, flexible substrates that conform to brain surfaces or peripheral neuronal fibers. In this study, we investigate the potential for using OLEDs to modulate neuronal networks cultured in vitro on a transparent microelectrode array (MEA) and subsequently validate neurostimulation in vivo in a transgenic mouse model.ApproachCultured mouse cortical neurons were transfected with light-sensitive opsins such as blue-light sensitive channel-rhodopsin (ChR2) and green-light sensitive chimeric channel-rhodopsin (C1V1tt) and stimulated using blue and green OLEDs (with 455 and 520 nm peak emission spectra respectively) at a power of 1 mW/mm2 under pulsed conditions.Main resultsWe demonstrate neuromodulation and optostimulus-locked, single unit-neuronal activity in neurons expressing stimulating and inhibiting opsins (n=4 MEAs, each with 16 recordable channels). We also validated the optostimulus-locked response in a channel-rhodopsin expressing transgenic mouse model, where at least three isolatable single neuronal cortical units respond to OLED stimulation.SignificanceThe above results indicate the feasibility of generating sufficient luminance from OLEDs to perform neuromodulation both in vitro and in vivo. This opens up the possibility of developing thin, flexible OLED films with multiple stimulation sites that can conform to the shape of the neuronal targets in the brain or the peripheral nervous system. However, stability of these OLEDs under chronic conditions still needs to be carefully assessed with appropriate packaging approaches.

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Microelectrode array-based system for neuropharmacological applications with cortical neurons cultured in vitro

Biosensors and Bioelectronics ◽

10.1016/j.bios.2006.09.026 ◽

2007 ◽

Vol 22 (11) ◽

pp. 2478-2484 ◽

Cited By ~ 44

Author(s):

Guangxin Xiang ◽

Liangbin Pan ◽

Lihua Huang ◽

Zhongyao Yu ◽

Xindong Song ◽

...

Keyword(s):

Cortical Neurons ◽

Microelectrode Array

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BrainPhys neuronal medium optimized for imaging and optogenetics in vitro

10.1101/2020.09.02.276535 ◽

2020 ◽

Author(s):

Michael Zabolocki ◽

Kasandra McCormack ◽

Mark van den Hurk ◽

Bridget Milky ◽

Andrew Shoubridge ◽

...

Keyword(s):

Neuronal Activity ◽

Cortical Neurons ◽

Cell Biology ◽

Cellular Reprogramming ◽

Synaptic Activity ◽

Neuronal Cultures ◽

Light Spectrum ◽

Human Neurons ◽

Wide Range

AbstractThe capabilities of imaging technologies, fluorescent sensors, and optogenetics tools for cell biology have improved exponentially in the last ten years. At the same time, advances in cellular reprogramming and organoid engineering have quickly expanded the use of human neuronal models in vitro. Altogether this creates an increasing need for tissue culture conditions better adapted to live-cell imaging. Here, we identified multiple caveats of traditional media when used for live imaging and functional assays on neuronal cultures (e.g., phototoxicity, suboptimal fluorescence signals, and unphysiological neuronal activity). To overcome these issues, we developed a new neuromedium, “BrainPhys™ Imaging”, in which we adjusted fluorescent and phototoxic compounds. The new medium is based on the formulation of the original BrainPhys medium, which we designed to better support the neuronal activity of human neurons in vitro1. We tested the new imaging-optimized formulation on human neurons cultured in monolayers or organoids, and rat primary neurons. BrainPhys Imaging enhanced fluorescence signals and reduced phototoxicity throughout the entire light spectrum. Importantly, consistent with standard BrainPhys, we showed that the new imaging medium optimally supports the electrical and synaptic activity of midbrain and human cortical neurons in culture. We also benchmarked the capacity of the new medium for functional calcium imaging and optogenetic control of human neurons. Altogether, our study shows that the new BrainPhys Imaging improves the quality of a wide range of fluorescence imaging applications with live neurons in vitro while supporting cell viability and neuronal functions.

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A mesh microelectrode array for non-invasive electrophysiology within neural organoids

10.1101/2020.09.02.279125 ◽

2020 ◽

Cited By ~ 1

Author(s):

Matthew McDonald ◽

David Sebinger ◽

Lisa Brauns ◽

Laura Gonzalez-Cano ◽

Yotam Menuchin-Lasowski ◽

...

Keyword(s):

Microelectrode Array ◽

Single Cells ◽

Three Dimensional ◽

Microelectrode Arrays ◽

Polymer Scaffolds ◽

Neural Models ◽

New Class ◽

Non Invasive

AbstractOrganoids are emerging in vitro models of human physiology. Neural models require the evaluation of functional activity of single cells and networks, which is best measured by microelectrode arrays. The characteristics of organoids clash with existing in vitro or in vivo microelectrode arrays. With inspiration from implantable mesh electronics and growth of organoids on polymer scaffolds, we fabricated suspended hammock-like mesh microelectrode arrays for neural organoids. We have demonstrated the growth of organoids enveloping these meshes, their cultivation for at least nine months, and could measure spontaneous electrical activity within organoids. Our concept should enable a new class of microelectrode arrays for in vitro models of three-dimensional electrically active tissue.

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Versatile live-cell activity analysis platform for characterization of neuronal dynamics at single-cell and network level

10.1101/2020.05.01.071787 ◽

2020 ◽

Cited By ~ 1

Author(s):

Xinyue Yuan ◽

Manuel Schröter ◽

Marie Engelene J. Obien ◽

Michele Fiscella ◽

Wei Gong ◽

...

Keyword(s):

Neuronal Networks ◽

Microelectrode Array ◽

Cell Activity ◽

Live Cell ◽

High Signal ◽

Neuronal Cultures ◽

Label Free ◽

Analysis Platform

AbstractChronic imaging of neuronal networks in vitro has provided fundamental insights into mechanisms underlying neuronal function. Existing labeling and optical imaging methods, however, cannot be used for continuous and long-term recordings of the dynamics and evolution of neuronal networks, as fluorescence indicators can cause phototoxicity. Here, we introduce a versatile platform for label-free, comprehensive and detailed electrophysiological live-cell imaging of various neurogenic cells and tissues over extended times. We report on a novel dual-mode high-density microelectrode array, which can simultaneously record in i) full-frame mode with 19,584 recording sites and ii) high-signal-to-noise mode with 246 channels. We set out to demonstrate the capabilities of this platform with recordings from primary and iPSC-derived neuronal cultures and tissue preparations over several weeks, providing detailed morpho-electrical phenotypic parameters at subcellular, cellular and network level. Moreover, we developed reliable analysis tools with drastically increased throughput for extracting axonal morphology and conduction parameters.

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In Vivo Dopamine Detection and Single Unit Recordings Using Intracortical Glassy Carbon Microelectrode Arrays

MRS Advances ◽

10.1557/adv.2018.98 ◽

2018 ◽

Vol 3 (29) ◽

pp. 1629-1634 ◽

Cited By ~ 10

Author(s):

Elisa Castagnola ◽

Nasim Winchester Vahidi ◽

Surabhi Nimbalkar ◽

Srihita Rudraraju ◽

Marvin Thielk ◽

...

Keyword(s):

Glassy Carbon ◽

Neural Activity ◽

Microelectrode Array ◽

Flexible Substrate ◽

Microelectrode Arrays ◽

European Starling ◽

Dopamine Detection ◽

Vertical Spacing

ABSTRACTIn this study, we present a 4-channel intracortical glassy carbon (GC) microelectrode array on a flexible substrate for the simultaneous in vivo neural activity recording and dopamine (DA) concentration measurement at four different brain locations (220µm vertical spacing). The ability of GC microelectrodes to detect DA was firstly assessed in vitro in phosphate-buffered saline solution and then validated in vivo measuring spontaneous DA concentration in the Striatum of European Starling songbird through fast scan cyclic voltammetry(FSCV). The capability of GC microelectrode arrays and commercial penetrating metal microelectrode arrays to record neural activity from the Caudomedial Neostriatum of European starling songbird was compared. Preliminary results demonstrated the ability of GC microelectrodes in detecting neurotransmitters release and recording neural activity in vivo. GC microelectrodes array may, therefore, offer a new opportunity to understand the intimate relations linking electrophysiological parameters with neurotransmitters release.

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Determination of the Time Course and Extent of Neurotoxicity at Defined Temperatures in Cultured Neurons Using a Modified Multiwell Plate Fluorescence Scanner

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/00004647-199704000-00011 ◽

1997 ◽

Vol 17 (4) ◽

pp. 455-463 ◽

Cited By ~ 24

Author(s):

Rita Sattler ◽

Milton P. Charlton ◽

Mathias Hafner ◽

Michael Tymianski

Keyword(s):

High Throughput ◽

Cortical Neurons ◽

Time Course ◽

Molecular Mechanisms ◽

Neuronal Cultures ◽

Lactate Dehydrogenase Release ◽

Cultured Cortical Neurons ◽

And Control

The cellular and molecular mechanisms of hypoxic/ischemic neurodegeneration are sensitive to numerous factors that modulate the time course and degree of neuronal death. Among such factors is hypothermia, which can dramatically protect neurons from injury. To examine and control for temperature-dependent effects, we developed a technique that provides for a high-throughput, accurate, and reproducible determination of the time course and degree of neurotoxicity in cultured cortical neurons at precisely defined temperatures. We used a fluorescence multiwell plate scanner, modified by us to permit the control of temperature, to perform serial quantitative measurements of propidium iodide (PI) fluorescence in cortical neuronal cultures exposed to excitotoxic insults. In validating this approach, we show that these time course measurements correlate highly with manual counts of PI-stained cells in the same cultures ( r = 0.958, p < 0.0001) and with lactate dehydrogenase release ( r = 0.964, p < 0.0001). This method represents an efficient approach to mechanistic and quantitative studies of cell death as well as a high-throughput technique for screening new neuroprotective therapies in vitro.

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