Integrated Microelectrode Arrays Research Articles

A Biomimetic Chip with Dendrimer-Encapsulated Platinum Nanoparticles for Enhanced Electrochemiluminescence Detection of Cardiac Troponin I

The measurement of cardiac troponin I (cTnI) is of vital importance for the early diagnosis of acute myocardial infarction. In this study, an enhanced electrochemiluminescent immunoassay for the highly sensitive and precise determination of cTnI was reported. A biomimetic chip with nepenthes peristome surface microstructures to achieve single-layer microbead arrays and integrated microelectrode arrays (MEAs) for ECL detection was microfabricated. Ru@SiO2 nanoparticles were prepared as signal amplificators labeling immunomagnetic beads. Dendrimer-encapsulated platinum nanoparticles (Pt DENs) were electrochemically modified on ITO MEAs. The resulting Pt DEN-modified ITO MEAs preserved good optical transparency and exhibited an approximately 20-fold ECL signal amplification compared to that obtained from bare ITO. The method made full use of the biomimetic chip with Pt DENs to develop single-layer immunomagnetic bead arrays with increasingly catalyzed electrochemical oxidation of the [Ru(bpy)3]2+–TPA system. Consequently, a limit of detection calculated as 0.38 pg/mL (S/N = 3) was obtained with excellent selectivity, demonstrating significant potential for the detection of cTnI in clinical diagnostics.

Electrical Characterization and Analysis of Single Cells and Related Applications.

Biological parameters extracted from electrical signals from various body parts have been used for many years to analyze the human body and its behavior. In addition, electrical signals from cancer cell lines, normal cells, and viruses, among others, have been widely used for the detection of various diseases. Single-cell parameters such as cell and cytoplasmic conductivity, relaxation frequency, and membrane capacitance are important. There are many techniques available to characterize biomaterials, such as nanotechnology, microstrip cavity resonance measurement, etc. This article reviews single-cell isolation and sorting techniques, such as the micropipette separation method, separation and sorting system (dual electrophoretic array system), DEPArray sorting system (dielectrophoretic array system), cell selector sorting system, and microfluidic and valve devices, and discusses their respective advantages and disadvantages. Furthermore, it summarizes common single-cell electrical manipulations, such as single-cell amperometry (SCA), electrical impedance sensing (EIS), impedance flow cytometry (IFC), cell-based electrical impedance (CEI), microelectromechanical systems (MEMS), and integrated microelectrode array (IMA). The article also enumerates the application and significance of single-cell electrochemical analysis from the perspectives of CTC liquid biopsy, recombinant adenovirus, tumor cells like lung cancer DTCs (LC-DTCs), and single-cell metabolomics analysis. The paper concludes with a discussion of the current limitations faced by single-cell analysis techniques along with future directions and potential application scenarios.

A Novel 3D Helical Microelectrode Array for In Vitro Extracellular Action Potential Recording.

Recent advances in cell and tissue engineering have enabled long-term three-dimensional (3D) in vitro cultures of human-derived neuronal tissues. Analogous two-dimensional (2D) tissue cultures have been used for decades in combination with substrate integrated microelectrode arrays (MEA) for pharmacological and toxicological assessments. While the phenotypic and cytoarchitectural arguments for 3D culture are clear, 3D MEA technologies are presently inadequate. This is mostly due to the technical challenge of creating vertical electrical conduction paths (or ‘traces’) using standardized biocompatible materials and fabrication techniques. Here, we have circumvented that challenge by designing and fabricating a novel helical 3D MEA comprised of polyimide, amorphous silicon carbide (a-SiC), gold/titanium, and sputtered iridium oxide films (SIROF). Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) testing confirmed fully-fabricated MEAs should be capable of recording extracellular action potentials (EAPs) with high signal-to-noise ratios (SNR). We then seeded induced pluripotent stems cell (iPSC) sensory neurons (SNs) in a 3D collagen-based hydrogel integrated with the helical MEAs and recorded EAPs for up to 28 days in vitro from across the MEA volume. Importantly, this highly adaptable design does not intrinsically limit cell/tissue type, channel count, height, or total volume.

Simultaneous measurement of contraction forces and field potentials of cardiomyocytes subjected to ion channel inhibitors

Cardiomyocytes (CMs) cultured on a micro engineered platform are essential in determining drug-induced cardiotoxicity and serving as a disease model in the preclinical stage. Despite significant advancements in related biotechnology, fully comprehending the complex functional properties of CMs composed of two- or three-dimensional tissue structures remains a challenge. This is due to the currently available biosensing platforms have been optimized to measure either electrophysiology or mechanophysiology of CMs. To overcome the limitation of the current state of the art, herein, we propose a unique biosensing platform capable of measuring both the contraction force and field potential of drug-induced CMs simultaneously. The contraction force and its correlation with the extracellular field potential of layered CMs cultured on a 10 µm thick polydimethylsiloxane (PDMS) diaphragm are measured in real-time using a laser vibrometer and integrated microelectrode arrays (MEAs). The layered CMs cultured on a nanogrooved PDMS diaphragm respond efficaciously to a Na+ channel inhibitor (Lidocaine), and the electro-/mechanophysiological measurements provides a correlation between Lidocaine's cardiotoxic effect on the contraction force and field potential signal of CMs.

Influence of microchannel geometry on device performance and electrophysiological recording fidelity during long-term studies of connected neural populations.

Compartmentalized microfluidic neural cell culture platforms, which physically separate axons from the neural soma using a series of microchannels, have been used for studying a wide range of pathological conditions and basic neuroscience questions. While each study has different experimental needs, the fundamental design of these devices has largely remained unchanged and a systematic study to establish long-term neural cultures in this format is lacking. Here, we investigate the influence of microchannel geometry and cell seeding density on device performance particularly in the context of long-term studies of synaptically-connected, yet fluidically-isolated neural populations of neurons and glia. Of the different experimental parameters, the microchannel height was the principal determinant of device performance, where the other parameters offer additional degrees of freedom in customizing such devices for specific applications. We condense the effects of these parameters into design rules and demonstrate their utility in engineering a microfluidic neural culture platform with integrated microelectrode arrays. The engineered device successfully recorded from primary rat cortical cells for 59 days in vitro with more than on order of magnitude enhancement in signal-to-noise ratio in the microchannels.

Real-Time Analysis of Oxygen Gradient in Oocyte Respiration Using a High-Density Microelectrode Array.

Physiological events related to oxygen concentration gradients provide valuable information to determine the state of metabolizing biological cells. The existing oxygen sensing methods (i.e., optical photoluminescence, magnetic resonance, and scanning electrochemical) are well-established and optimized for existing in vitro analyses. However, such methods also present various limitations in resolution, real-time sensing performance, complexity, and costs. An electrochemical imaging system with an integrated microelectrode array (MEA) would offer attractive means of measuring oxygen consumption rate (OCR) based on the cell’s two-dimensional (2D) oxygen concentration gradient. This paper presents an application of an electrochemical sensor platform with a custom-designed complementary-metal-oxide-semiconductor (CMOS)-based microchip and its Pt-coated surface MEA. The high-density MEA provides 16,064 individual electrochemical pixels that cover a 3.6 mm × 3.6 mm area. Utilizing the three-electrode configuration, the system is capable of imaging low oxygen concentration (18.3 µM, 0.58 mg/L, or 13.8 mmHg) at 27.5 µm spatial resolution and up to 4 Hz temporal resolution. In vitro oxygen imaging experiments were performed to analyze bovine cumulus-oocytes-complexes cells OCR and oxygen flux density. The integration of a microfluidic system allows proper bio-sample handling and delivery to the MEA surface for imaging. Finally, the imaging results are processed and presented as 2D heatmaps, representing the dissolved oxygen concentration in the immediate proximity of the MEA. This paper provides the results of real-time 2D imaging of OCR of live cells/tissues to gain spatial and temporal dynamics of target cell metabolism.

An integrated microelectrode array system for neural signals recording

A CMOS neural signal recording microelectrode array system integrated with signal processing circuits is proposed in this work. A model of the electrode-neuron interface is built. Analytic derivation and simulation results reveal some interesting phenomena and provide a theoretical basis for the design of the Micro-Electrodes Array (MEA) which is a crucial direction for optimizing MEA and improving Signal-to-Noise Ratio (SNR). The new Operational Trans-conductance Amplifier (OTA) utilizes a Flipped Voltage Follower (FVF) topology to effectively decrease the power supply voltage and power consumption while still keeping the gain, Power Supply Rejection Ratio (PSRR) and Common Mode Rejection Ratio (CMRR) at a high value and the noise at a low level. Using the active low-frequency suppression instrumentation amplification technique, the proposed system topology ameliorates the disadvantage of the conventional capacitive coupling structure which occupies a large area. An 8-channel prototype was fabricated in a 0.5 μm standard CMOS process, occupying 5 × 5 mm2. The prototype OTA consumes less than 3 μW, providing 11.9 μVrms input referred noise with 83.9 dB CMRR and 99.4 dB PSRR, which providing an effective method for in vitro neural studies.

An AUC-based impedance sensing method for rapid assessment of antioxidant compounds with NIH-3T3 cells cultured in a 16-well E-plate with integrated microelectrode arrays

To seek for a rapid, efficient and more physiologically relevant method for assessment of antioxidant phenols, the real-time impedance sensing technique was employed for label-free and dynamic measurement of cell response to phenolic compounds under H2O2-induced oxidative stress in a 16-well E-plate with integrated microelectrode arrays at the bottom of each well to monitor the electrical impedance changes due to cell adhesion and number. The area under the impedance response curve (AUC) was proposed to reflect the cumulative chemical effects on fibroblast NIH-3T3 cells. Four longan seed polyphenols with different antioxidant potency were used to test the feasibility of the impedance method. Our results showed that the AUC-based impedance data correlated well with the conventional cell-based endpoint results including antioxidant enzyme activities and reactive oxygen species (ROS) level. The conclusion was further validated by using 12 kinds of representative and well-studied antioxidant phenols. Our data strongly suggested that the AUC- and fibroblast cell-based impedance method could serve as an alternative to existing traditional cell-based endpoint assays for rapid assessment and primary screening of phenolic compounds. This method is non-invasive, highly sensitive, inexpensive and time-saving, and has potential to be a high-throughput approach in a more physiologically relevant manner.

ELECTROPHYSIOLOGICAL PHENOTYPE CHARACTERIZATION OF HUMAN IPSC-DERIVED DOPAMINERGIC NEURONAL LINES BY MEANS OF HIGH-RESOLUTION MICROELECTRODE ARRAYS

Event Abstract Back to Event ELECTROPHYSIOLOGICAL PHENOTYPE CHARACTERIZATION OF HUMAN IPSC-DERIVED DOPAMINERGIC NEURONAL LINES BY MEANS OF HIGH-RESOLUTION MICROELECTRODE ARRAYS Michele Fiscella1, 2*, Noelle Leary1, Ebru Acun1, Silvia Ronchi1 and Andreas Hierlemann1 1 ETH Zürich, Switzerland 2 MaxWell Biosystems, Switzerland High-resolution-microelectrode-array (MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity (Müller et. al, Lab on a Chip, 2015). We have used this MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural culture development. Astrocyte/neuron co-cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple MEA recording sessions compared to neural cultures without astrocytes. We compared velocities of action potential propagation along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease-model neurons, axonal action potential propagation velocities were lower than, for example, in rat primary cortical neurons (Bakkum et. al, Nature Communications, 2013). Furthermore, we found different axonal action-potential-velocity development profiles of A53T α-synuclein dopaminergic neurons and the wild-typecell line. Finally, we were able to precisely and reproducibly evoke action potentials in individual single human IPSC-derived neurons through subcellular-resolution electrical stimulation. High-resolution MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing. Acknowledgements EU, ERC Advanced Grant “neuroXscales” contract number 694829 EU, ERC-PoC “MwHresEP" contract number 755383 CH, Project CTI-No. 25933. 2 PFLS-LS “Multi-well electrophysiology platform for high-throughput cell-based assays” References J. Müller, M. Ballini, P. Livi, Y. Chen, M. Radivojevic, A. Shadmani, V. Viswam, I. L. Jones, M. Fiscella, R. Diggelmann, A. Stettler, U. Frey, D. J. Bakkum, A. Hierlemann, "High-resolution CMOS MEA platform to study neurons at subcellular, cellular, and network levels", Lab Chip, 2015, 15, pp. 2767-2780 (DOI: 10.1039/C5LC00133A) Douglas J. Bakkum, Urs Frey, Milos Radivojevic, Thomas L. Russell, Jan Müller, Michele Fiscella, Hirokazu Takahashi, Andreas Hierlemann, "Tracking Axonal Action Potential Propagation on a High-density Microelectrode Array across Hundreds of Sites", Nature Communications, 2013, 4:2181 (DOI: 10.1038/ncomms3181). Keywords: CMOS-MEAs, IPSC-derived neurons, Parkinson Disease, microelectrode arrays, phenotyping Conference: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays, Reutlingen, Germany, 4 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Stem cell-derived applications Citation: Fiscella M, Leary N, Acun E, Ronchi S and Hierlemann A (2019). ELECTROPHYSIOLOGICAL PHENOTYPE CHARACTERIZATION OF HUMAN IPSC-DERIVED DOPAMINERGIC NEURONAL LINES BY MEANS OF HIGH-RESOLUTION MICROELECTRODE ARRAYS. Conference Abstract: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays. doi: 10.3389/conf.fncel.2018.38.00014 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Mar 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. Michele Fiscella, ETH Zürich, Zurich, Switzerland, michele.fiscella@mxwbio.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Michele Fiscella Noelle Leary Ebru Acun Silvia Ronchi Andreas Hierlemann Google Michele Fiscella Noelle Leary Ebru Acun Silvia Ronchi Andreas Hierlemann Google Scholar Michele Fiscella Noelle Leary Ebru Acun Silvia Ronchi Andreas Hierlemann PubMed Michele Fiscella Noelle Leary Ebru Acun Silvia Ronchi Andreas Hierlemann Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

High-throughput impedance-based cell adhesion and migration assay with single-cell resolution using CMOS microelectrode array

High-throughput impedance-based cell adhesion and migration assay with single-cell resolution using CMOS microelectrode array

High-Throughput CMOS MEA System with Integrated Microfluidics for Cardiotoxicity Studies

High-Throughput CMOS MEA System with Integrated Microfluidics for Cardiotoxicity Studies

Electrophysiological Pain Responses in Cultured Human iPSC-Derived Sensory Neurons Using High-Throughput Multi-Electrode Array System

Event Abstract Back to Event Electrophysiological Pain Responses in Cultured Human iPSC-Derived Sensory Neurons Using High-Throughput Multi-Electrode Array System Aoi Odawara1, 2, 3, Naoki Matsuda1 and Ikuro Suzuki1, 4, 5* 1 Tohoku Institute of Technology, Department of Electronics, Japan 2 Tohoku University, AIMR, Japan 3 Japan Society for the Promotion of Science (JSPS), Japan 4 Japan Agency for Medical Research and Development (AMED), Japan 5 Consortium for Safety Assessment using Human iPS Cells (CSAHi), Japan Dorsal root ganglion (DRG) sensory neurons are pain-related neurons and have a variety of sensory receptors that are activated by chemical, thermal, and mechanical stimuli. Establishment of pharmacological assay in pain research and drug screening is important issue. In addition, human induced pluripotent stem cell (hiPSC)-derived sensory neurons may be effectively used for drug discovery and toxicity testing. The purpose of this study was to evaluate the physiological responses against typical pain-related molecules, temperature change and anti-cancer drug in cultured sensory neurons using high-throughpupt multi-electrode array (MEA) system. Human iPSC-derived sensory neurons were cultured on MEA chips, and the electrophysiological responses against capsaicin, menthol, allyl isothiocyanate (AITC), anti-cancer drug vincristine and oxaliplatin were measured by the MEA system. To confirm the responses depending on each receptor, we examined the responses in presence of each receptor antagonist. We also examined whether the increase of cold sensitivities occur in presence of anticancer drug in vitro hiPSC-derived sensory neurons. We firstly confirmed the expression of typical sensory marker Nav1.7, TRPV1, TRPM8, and TRPA1 using immunostaining in culture hiPSC-derived sensory neurons at 8 weeks culture. Evoked responses against capsaicin, menthol, and AITC were detected. As the responses disappeared with each channle bloker, these responses were confirmed to be channel specific responses. The evoked responses against anticancer drug vincristine and oxaliplatin were also detected. Furthermore, we found that the responses against AITC increase in presence oxaliplatin and with the concentration of oxaliplatin. We have succeeded in detecting the electrophysiological pain reponses against capsaicin, menthol, allyl isothiocyanate (AITC), anti-cancer drug vincristine and oxaliplatin in hiPSC-derived sensory neurons using MEA system. We found that the increase of cold sensitivities in vivo phenomenon was also detected in vitro hiPSC-derived sensory neurons. Keywords: hiPSC-derived sensory neurons, TRP channels, Anti-cancer drug, Pharmacology, High-Throughput MEA system Conference: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays, Reutlingen, Germany, 4 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Stem cell-derived applications Citation: Odawara A, Matsuda N and Suzuki I (2019). Electrophysiological Pain Responses in Cultured Human iPSC-Derived Sensory Neurons Using High-Throughput Multi-Electrode Array System. Conference Abstract: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays. doi: 10.3389/conf.fncel.2018.38.00060 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Mar 2018; Published Online: 17 Jan 2019. * Correspondence: Prof. Ikuro Suzuki, Tohoku Institute of Technology, Department of Electronics, Sendai, Japan, s.ikurou@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Aoi Odawara Naoki Matsuda Ikuro Suzuki Google Aoi Odawara Naoki Matsuda Ikuro Suzuki Google Scholar Aoi Odawara Naoki Matsuda Ikuro Suzuki PubMed Aoi Odawara Naoki Matsuda Ikuro Suzuki Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Multielectrode array recordings of human iPSC-derived neurons reveal differences in network activity depending on differentiation protocol and genome modification

Event Abstract Back to Event Multielectrode array recordings of human iPSC-derived neurons reveal differences in network activity depending on differentiation protocol and genome modification Sandra K. Fischer1* and Frank Gillardon1 1 Boehringer Ingelheim (Germany), Germany With increasing prevalence of neuropsychiatric disorders, there is an ever-growing need for suitable model systems to understand the underlying pathological mechanisms. Currently most data are derived from animal models, although correlations between animal and human are often weak. However, acquisition of human neuronal material is rarely possible and afflicted with ethic concerns. Human induced pluripotent stem cell (hiPSC) derived neuronal cultures offer a possibility to overcome these limitations. Synaptic activity and neurotransmission deficits have been identified as core pathophysiologies of neuropsychiatric disorders. The multi electrode array (MEA) technology allows for repeated measurements of electrical activity of functional neuronal networks over an extended period of time. We cultivated iPSC-derived neuronal cultures on the Multichannel Systems MEA multiwell platform and assessed synaptic activity over time and in response to treatment with pharmacological agents. The hiPSC-derived neurons developed electrical activity from single spikes to bursts over time indicating maturation. Dot-seeded GlutaNeurons (iCell Neurons, Cellular Dynamics International) showed their peak activity after 2-3 weeks in culture with the highest burst activity in week 3. Ngn2-induced Neurons (iCell Neurons, Cellular Dynamics International) displayed a weaker total activity with lower spike rate, less burst activity and a maximum activity after 6 weeks in culture. Treatment with the GABA antagonist Bicuculline evoked synchronized burst firing in GlutaNeuron cultures containing approx. 20% GABAergic neurons, whereas the spontaneous activity of the purely glutamatergic culture of Induced Neurons was unchanged as expected. Loss-of-function mutations in ErbB receptor tyrosine kinases have been identified as genetic risk factors for neuropsychiatric diseases. Upon pharmacological inhibition of ErbB receptor tyrosine kinases, neuronal network activity was inhibited, consistent with our MEA recordings from primary rat cortical neuron cultures. Moreover, we generated a loss-of-function mutation in a high risk gene for schizophrenia in hiPSC from a healthy donor utilizing the CRISPR/Cas9 gene editing system. Following neuronal differentiation into the forebrain lineage electrophysiological activity was monitored on the MEA multiwell system during network formation and maturation. Preliminary data indicate altered spontaneous network activity in mutant iPSC-derived neurons compared to isogenic controls. In summary, our findings demonstrate that hiPSC-derived neurons form functional neuronal networks on MEA plates which can serve as suitable system for modeling of neuropsychiatric diseases. Acknowledgements The authors thank Dr. Sabine Lange (Cellular Dynamics International) for helpful discussions. Keywords: IPSC-derived neurons, neuropsychiatric disorder, electrical network activity, multielectrode array plate, CRISPR/Cas9 gene editing Conference: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays, Reutlingen, Germany, 4 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Stem cell-derived applications Citation: Fischer SK and Gillardon F (2019). Multielectrode array recordings of human iPSC-derived neurons reveal differences in network activity depending on differentiation protocol and genome modification. Conference Abstract: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays. doi: 10.3389/conf.fncel.2018.38.00015 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 12 Mar 2018; Published Online: 17 Jan 2019. * Correspondence: Mrs. Sandra K Fischer, Boehringer Ingelheim (Germany), Hannover, Germany, sandra.fischer@boehringer-ingelheim.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sandra K Fischer Frank Gillardon Google Sandra K Fischer Frank Gillardon Google Scholar Sandra K Fischer Frank Gillardon PubMed Sandra K Fischer Frank Gillardon Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Cerebrospinal fluid from Dementia with Lewy body patients suppresses neuronal network activity

Cerebrospinal fluid from Dementia with Lewy body patients suppresses neuronal network activity

Electrical Impedance Tomography on High-density Microelectrode Arrays

Electrical Impedance Tomography on High-density Microelectrode Arrays

Mesoscale network architecture regulates spontaneous activity

Event Abstract Back to Event Mesoscale network architecture regulates spontaneous activity Samora Okujeni1, 2* and Ulrich Egert1, 2 1 Albert Ludwigs Universität Freiburg, Department of Microsystems Engineering, IMTEK, Germany 2 Bernstein Zentrum Freiburg, Albert Ludwigs Universität Freiburg, Germany Spontaneous network activity robustly emerges in developing neuronal networks in vivo and in vitro. The neurophysiological and anatomical requirements for the generation of such activity, however, are poorly understood. Network simulations indicate that clustered connectivity may foster the generation, maintenance and richness of spontaneous activity. Since this mesoscale architecture cannot be systematically modified in living animals, testing these predictions is impracticable in vivo. Here, we investigate how the mesoscale architecture shapes spontaneous activity in developing networks of rat cortical neurons in vitro. In these networks, neurons spontaneously arrange into local clusters with high neurite density and form fasciculating long-range axons. We modified this structure by modulation of protein kinase C, an enzyme regulating neurite growth and cell migration. Inhibition of protein kinase C reduced neuronal aggregation and fasciculation of axons, i.e. promoted uniform architecture. Conversely, activation of protein kinase C promoted aggregation of neurons into clusters, local connectivity and bundling of long-range axons. Supporting predictions from theory, clustered networks were more spontaneously active and generated diverse activity patterns. Neurons within clusters received stronger synaptic inputs and displayed increased membrane potential fluctuations. Intensified clustering promoted the initiation of synchronous bursting events but entailed incomplete network recruitment. Moderately clustered networks appear optimal for initiation and propagation of diverse patterns of activity. Our findings support a crucial role of the mesoscale architectures in the regulation of spontaneous activity dynamics. Acknowledgements This work was supported by BrainLinks-BrainTools, Cluster of Excellence funded by the German Research Foundation (Grant EXC 1086), and Bernstein Focus: Neurotechnology Freiburg–Tuebingen (FKZ 01GQ0420). References Okujeni S, Kandler S, Egert U (2017) Mesoscale Architecture Shapes Initiation and Richness of Spontaneous Network Activity. J Neurosci 37:3972–3987. Keywords: development, connectivity, PKC, spontaneous activity, in vitro culture Conference: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays, Reutlingen, Germany, 4 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Neural Networks Citation: Okujeni S and Egert U (2019). Mesoscale network architecture regulates spontaneous activity. Conference Abstract: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays. doi: 10.3389/conf.fncel.2018.38.00042 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 17 Mar 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. Samora Okujeni, Albert Ludwigs Universität Freiburg, Department of Microsystems Engineering, IMTEK, Freiburg, Baden Wuerttemberg, 79110, Germany, okujeni@bcf.uni-freiburg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Samora Okujeni Ulrich Egert Google Samora Okujeni Ulrich Egert Google Scholar Samora Okujeni Ulrich Egert PubMed Samora Okujeni Ulrich Egert Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Fabrication of Multi-Electrode Array with Iridium Oxide-Electrodeposited on Indium-Tin Oxides Nanowires

Event Abstract Back to Event Fabrication of Multi-Electrode Array with Iridium Oxide-Electrodeposited on Indium-Tin Oxides Nanowires Yonghee KIM1, SNAG-DON JUNG1*, Ho Koo2 and Min Sun Kim2 1 Electronics and Telecommunications Research Institute, Republic of Korea 2 Wonkwang University, Department of Physiology, Republic of Korea Multi-electrode arrays (MEAs) were fabricated with electrodes consisting of iridium oxide (IrOx) electrodeposited on indium-tin oxide nanowires (ITO NWs) grown on ITO electrode using RF magnetron sputtering technique. The elemental mapping analysis of the cross-sectional structure of the IrOx/ITO NW hybrid electrodes revealed that the IrOx had been uniformly deposited on the surface of the surface of ITO nanowire. The charge injection limit of the IrOx/ITO NW MEA was estimated to be 1.9 mC cm-2 by measuring the voltage transient, and this value is sufficiently greater than the neural damage threshold (ca. 1 mC cm-2). The efficacy of the improvement in the charge injection limit of the IrOx/ITO NW MEA was evaluated with rat hippocampal slices. The IrOx/ITO NW electrodes exhibited a steeper increase in the negative peak amplitude of the field excitatory postsynaptic potentials, even with an electrical stimulation of a lower amplitude, prolonged negative fEPSPs wave after peak response, all of which strongly indicate an improved charge injection for the IrOx/ITO NW MEA. Acknowledgements This work was supported by ETRI (18ZH1500). Keywords: Indium-tin oxide nanowire, electrodeposited iridium oxide, multielectrode array, Electrical Stimulation, Charge injection limit, Field excitatory postsynaptic potential, Long-Term Potentiation Conference: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays, Reutlingen, Germany, 4 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Microelectrode Array Technology Citation: KIM Y, JUNG S, Koo H and Kim M (2019). Fabrication of Multi-Electrode Array with Iridium Oxide-Electrodeposited on Indium-Tin Oxides Nanowires. Conference Abstract: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays. doi: 10.3389/conf.fncel.2018.38.00107 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Mar 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. SNAG-DON JUNG, Electronics and Telecommunications Research Institute, Daejeon, 34129, Republic of Korea, jungpol@etri.re.kr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Yonghee KIM SNAG-DON JUNG Ho Koo Min Sun Kim Google Yonghee KIM SNAG-DON JUNG Ho Koo Min Sun Kim Google Scholar Yonghee KIM SNAG-DON JUNG Ho Koo Min Sun Kim PubMed Yonghee KIM SNAG-DON JUNG Ho Koo Min Sun Kim Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Structural characterization and disinfection assessment of isogenic E.coli biofilms using impedance spectroscopy with microelectrode arrays

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