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Realization of a diamond based high density multi electrode array by means of Deep Ion Beam Lithography

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS 2015年 348卷 199-202页

作者： Picollo, F. Battiato, A. Bernardi, E. Boarino, L. Enrico, E. Forneris, J. Monticone, D. Gatto Olivero, P. INFN Sez Torino Turin Italy Univ Turin Dept Phys Turin Italy Univ Turin NIS Interdept Ctr Turin Italy Consorzio Nazl Interuniver Sci Fis Mat CNISM Sez Torino Turin Italy Natl Inst Metrol Res INRiM Nanofacil Piemonte Turin Italy

In the present work we report about a parallel-processing ion beam fabrication technique whereby high-density sub-superficial graphitic microstructures can be created in diamond. Ion beam implantation is an effective tool for the structural modification of diamond: in particular ion-damaged diamond can be converted into graphite, therefore obtaining an electrically conductive phase embedded in an optically transparent and highly insulating matrix. The proposed fabrication process consists in the combination of Deep Ion Beam Lithography (DIBL) and Focused Ion Beam (FIB) milling. FIB micromachining is employed to define micro-apertures in the contact masks consisting of thin (<10 mu m) deposited metal layers through which ions are implanted in the sample. A prototypical single-cell biosensor was realized with the above described technique. The biosensor has 16 independent electrodes converging inside a circular area of 20 mu m diameter (typical neuroendocrine cells size) for the simultaneous recording of amperometric signals. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Deep Ion Beam Lithography Diamond Biosensors multi electrode array

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Interpretation of field potentials measured on a multi electrode array in pharmacological toxicity screening on primary and human pluripotent stem cell-derived cardiomyocytes

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BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 2018年第4期497卷 1135-1141页

作者： Tertoolen, L. G. J. Braam, S. R. van Meer, B. J. Passier, R. Mummery, C. L. Leiden Univ Med Ctr Dept Anat & Embryol Einthovenweg 20 NL-2300 RC Leiden Netherlands Pluriomics BV Biopartner Bldg 3Galileiweg 8 NL-2333 BD Leiden Netherlands Univ Twente MIRA Inst Biomed Technol & Tech Med Dept Appl Stem Cell Technol NL-7500 AE Enschede Netherlands

multi electrode arrays (MEAs) are increasingly used to detect external field potentials in electrically active cells. Recently, in combination with cardiomyocytes derived from human (induced) pluripotent stem cells they have started to become a preferred tool to examine newly developed drugs for potential cardiac toxicity in pre-clinical safety pharmacology. The most important risk parameter is proarrhythmic activity in cardiomyocytes which can cause sudden cardiac death. Whilst MEAs can provide medium- to high-throughput noninvasive assay platform, the translation of a field potential to cardiac action potential (normally measured by low-throughput patch clamp) is complex so that accurate assessment of drug risk to the heart is in practice still challenging. To address this, we used computational simulation to study the theoretical relationship between aspects of the field potential and the underlying cardiac action potential. We then validated the model in both primary mouse- and human pluripotent (embryonic) stem cell-derived cardiomyocytes showing that field potentials measured in MEAs could be converted to action potentials that were essentially identical to those determined directly by electro-physiological patch clamp. The method significantly increased the amount of information that could be extracted from MEA measurements and thus combined the advantages of medium/high throughput with more informative readouts. We believe that this will benefit the analysis of drug toxicity screening of cardiomyocytes using in time and accuracy. (C) 2017 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license

关键词： Action potential Field potential Cardiomyocytes Cardiotoxicity multi electrode array Computational simulation

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A modular multi electrode array system for electrogenic cell characterisation and cardiotoxicity applications

A modular multi electrode array system for electrogenic cell...

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作者： Olivia M. Flaherty Loughborough University

学位级别：博士

multi electrode array (MEA) systems have evolved from custom-made experimental tools, exploited for neural research, into commercially available systems that are used throughout non-invasive electrophysiological study. MEA systems are used in conjunction with cells and tissues from a number of differing organisms (e. g. mice, monkeys, chickens, plants). The development of MEA systems has been incremental over the past 30 years due to constantly changing specific bioscientific requirements in research. As the application of MEA systems continues to diversify contemporary commercial systems are requiring increased levels of sophistication and greater throughput capabilities. This research has identified current requirements of MEA systems. Generic system requirements, and application specific requirements, have been identified and prioritised. Product design specifications were drafted and a novel MEA biochip concept was designed. Manufacturing approach experimentation occurred until a suitable prototype of the biochip concept was produced. This first generation of prototype was tested by MEA system users at the University of Nottingham. User feedback and testing outcomes resulted in development of a second design concept that was also manufactured and tested. The research presented in this thesis identifies areas within the field of MEA technology application where design changes can bring significant benefits to MEA system users, especially to stem cell- derived cardiomyocyte MEA system users. This thesis presents novel MEA biochip design concepts designed to address specific needs of MEA system users. The prototypes that were manufactured and tested have demonstrated promise within this application domain. Further work is required to achieve robust signal acquisition from the designs presented. The results of prototype testing have also been shared internationally at conference and through journal publications.

关键词： multi electrode array Stem cell-derived cardiomyocyte Biosensor fabrication

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All-carbon-nanotube flexible multi-electrode array for neuronal recording and stimulation

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BIOMEDICAL MICRODEVICES 2014年第1期16卷 43-53页

作者： David-Pur, Moshe Bareket-Keren, Lilach Beit-Yaakov, Giora Raz-Prag, Dorit Hanein, Yael Tel Aviv Univ Sch Elect Engn IL-6997801 Tel Aviv Israel Tel Aviv Univ Ctr Nanosci & Nanotechnol IL-6997801 Tel Aviv Israel

Neuro-prosthetic devices aim to restore impaired function through artificial stimulation of the nervous system. A lingering technological bottleneck in this field is the realization of soft, micron sized electrodes capable of injecting enough charge to evoke localized neuronal activity without causing neither electrode nor tissue damage. Direct stimulation with micro electrodes will offer the high efficacy needed in applications such as cochlear and retinal implants. Here we present a new flexible neuronal micro electrode device, based entirely on carbon nanotube technology, where both the conducting traces and the stimulating electrodes consist of conducting carbon nanotube films embedded in a polymeric support. The use of carbon nanotubes bestows the electrodes flexibility and excellent electrochemical properties. As opposed to contemporary flexible neuronal electrodes, the technology presented here is both robust and the resulting stimulating electrodes are nearly purely capacitive. Recording and stimulation tests with chick retinas were used to validate the advantageous properties of the electrodes and demonstrate their suitability for high-efficacy neuronal stimulation applications.

关键词： Carbon nanotubes multi electrode array Neuronal recording Neuronal stimulation Flexible Prosthesis

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Calcium Imaging of cultured neuronal network on multi-electrode array (MEA)

Calcium Imaging of cultured neuronal network on multi-electr...

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3rd International Conference on Photonics and Imaging in Biology and Medicine

作者： Zhou, W Li, XN Zeng, SQ Luo, QM Huazhong Univ Sci & Technol Minist Educ Key Lab Biomed Photon Wuhan 430074 Peoples R China

ISBN: (纸本)081945138X

As a ubiquitous intracellular signal, calcium is responsible for controlling numerous cellular processes, such as neuronal signal transmission. In this paper we show that calcium imaging of cultured neuronal network from hippocampus of newborn rats, revealed synchronized calcium wave in intracellular Ca2+ concentration and induced calcium oscillation by stimulating embedded-microelectrode on glass substrate.

关键词： neuronal network confocal multi electrode array calcium imaging

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Electrical stimulation of different retinal components and the effect of asymmetric pulses

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JOURNAL OF NEUROSCIENCE METHODS 2017年 291卷 20-27页

作者： Raz-Prag, Dorit Beit-Yaakov, Giora Hanein, Yael Tel Aviv Univ Ctr Nanosci & Nanotechnol IL-69978 Tel Aviv Israel Tel Aviv Univ Sch Elect Engn IL-69978 Tel Aviv Israel

Background: High resolution electrical stimulation of neural tissue is a fundamental challenge in applications such as deep brain stimulation and artificial vision. In artificial vision, achieving and validating local selective epi-retinal stimulation of different layers in the retina is particularly challenging owing to plurality of retinal cell types and delocalized wiring. Results: Strong selectivity and non-localized responses to epi-retinal stimulation, over a wide range of realistic stimulation parameters, was achieved and validated using asymmetric pulses. New method: The reported method consists of multi electrode array (MEA) stimulation and recording from a developing chick retina combined with calcium imaging. Data show direct and indirect neuronal activation in the chick retina model. In particular, axonal activation, orientation and conduction velocity are derived, and the non-local nature of the responses to direct axonal stimulation is demonstrated. Comparison with existing methods: Some of the previous research with mammalian retinas demonstrated local responses around the stimulating electrode, revealing little as to axonal activation. Recent studies showed activation along the nerve fibers and studied the effect of pulse duration to improve stimulation localization (Twyford and Fried, 2016;Weitz et al., 2015). The chick retina offers a straight forward mapping of axonal activation. Here we demonstrate that the chick retina, combined with MEA recording and stimulation along with calcium imaging is a powerful tool to study retinal activation and in particular the effect of asymmetry on axonal activation. Conclusions: MEA recording and stimulation from the chick retina is exceptionally powerful in distinguishing between direct and indirect responses. This method facilitates comparison between different stimulation strategies. We show that asymmetric electrical stimulations allow control over the intensity of direct activation. (C) Published by Elsevier

关键词： Artificial retina Stimulation multi electrode array

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Assessment of acute and chronic toxicity of doxorubicin in human induced pluripotent stem cell-derived cardiomyocytes

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TOXICOLOGY IN VITRO 2017年 42卷 182-190页

作者： Louisse, Jochem Wust, Rob C. I. Pistollato, Francesca Palosaari, Taina Barilari, Manuela Macko, Peter Bremer, Susanne Prieto, Pilar European Commiss Joint Res Ctr Directorate Hlth Consumers & Reference Mat F Ispra Italy Acad Med Ctr Lab Genet Metab Dis Amsterdam Netherlands

The present study assesses acute and chronic toxicity of doxorubicin in human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs), with the aim to obtain in vitro biomarkers that can be used as readouts to predict in vivo cardiotoxicity. Possible acute toxicity was investigated by assessing effects on the beating rate and the field potential duration (FPD) of doxorubicin-exposed cardiomyocytes by measuring electrical activity using multi-electrode array (MEA) analyses. No effects on the beating rate and FPD were found at concentrations up to 6 mu M, whereas at 12 mu M no electrical activity was recorded, indicating that the cardiomyocytes stopped beating. Acute and chronic effects of doxorubicin on mitochondria, which have been reported to be affected in doxorubicin-induced cardiotoxicity, were assessed using high content imaging techniques. To this end hiPSC-CMs were exposed to 150 or 300 nM doxorubicin using both single dosing (3 h and 2 days) and repetitive dosing (3 times, of 2 days each), including washout studies to assess delayed effects (assessment at day 14) and effects on cell number, mitochondrial density, mitochondrial membrane potential, mitochondrial superoxide levels and mitochondrial calcium levels were assessed. No effects of doxorubicin were found on mitochondrial density and mitochondrial superoxide levels, whereas doxorubicin reduced cell survival and slightly altered mitochondrial membrane potential and mitochondrial calcium levels, which was most profound in the washout studies. Altogether, the results of the present study show that concentrations of doxorubicin in the micromolar range were required to affect electrical activity of hiPSC-CMs, whereas nanomolar concentrations already affected cell viability and caused mitochondrial disturbances. Integration of these data with other in vitro data may enable the selection of a series of in vitro biomarkers that can be used as readouts to screen chemicals for possible cardiotoxicity.

关键词： Doxorubicin Cardiotoxicity Mitochondria In vitro Induced pluripotent stem cells High content imaging multi electrode array

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Physiological contribution of P2X receptors in postreceptoral signal processing in the mouse retina

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NEUROSCIENCE RESEARCH 2017年第0期115卷 5-12页

作者： Ichinohe, Sho Ishii, Toshiyuki Takahashi, Hiroshi Kaneda, Makoto Nippon Med Sch Dept Physiol Bunkyo Ku 1-1-5 Sendagi Tokyo 1138602 Japan Nippon Med Sch Dept Ophthalmol Bunkyo Ku 1-1-5 Sendagi Tokyo 1138602 Japan

ATP activates P2X receptors and acts as a neurotransmitter in the nervous system. We have previously reported that P2X receptors modulate the firing rate of retinal ganglion cells. Since many subtypes of P2X receptors are distributed in the mouse retina, it is likely that the modulatory effects of P2X receptor mediated signaling can occur at multiple synaptic levels in the retina. In this study, we investigated whether P2X receptors expressed between the photoreceptor layer and the inner nuclear layer in the mouse retina were physiologically functional, by electroretinography (ERG). In the combined rod-cone ERG and the scotopic ERG, intravitreal injection of PPADS, an antagonist of P2X receptors, had no effects on the amplitude of the a-wave, but decreased the amplitude of the b-wave. In the photopic ERG, intravitreal injection of PPADS significantly decreased the amplitude of both the a-wave and the b-wave. In ex vivo recordings, a decrease in the b-wave amplitude was observed at 20 mu M PPADS, confirming that the inhibition of the b-wave by intravitreal injection of PPADS is due to the inhibition of P2X receptors. Our findings suggest that P2X receptor-mediated signaling has a physiological effect in both the rod and the cone pathways in postreceptoral processing. (c) 2016 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

关键词： ATP PPADS P2X receptor Mouse Retina Electroretinogram multi electrode array

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multivariate Autoregressive-based Neuronal Network Flow Analysis for In-vitro Recorded Bursts 22nd

Multivariate Autoregressive-based Neuronal Network Flow Anal...

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22nd International Conference on Neural Information Processing (ICONIP)

作者： Hettiarachchi, Imali T. Bhatti, Asim Adlard, Paul A. Nahavandi, Saeid Deakin Univ Ctr Intelligent Syst Res Geelong Vic 3217 Australia Florey Inst Neurosci & Mental Hlth Synapt Neurobiol Lab Melbourne Vic Australia

ISBN: (纸本)9783319265612;9783319265605

Neuroscientific studies of in vitro neuron cell cultures has attracted paramount attention to investigate the behaviour of neuronal networks in response to different environmental conditions and external stimuli such as drugs, optical and electrical stimulations. Microelectrode array (MEA) technology has been widely adopted as a tool for this investigation. In this work, we present a new approach to estimate inter-connectivity of neural spikes using multivariate autoregressive (MVAR) analysis and Partial Directed Coherence (PDC). The proposed approach has the potential to discover hidden intra-burst causal connectivity patterns and to help understand the spatiotemporal communication patterns within bursts, pre and post stimulations.

关键词： multi electrode array Bursts Partial directed coherence multivariate autoregressive modelling

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Charactering hESCs Organoids from Electrical Signals with Machine Learning

Charactering hESCs Organoids from Electrical Signals with Ma...

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IEEE EMBS International Conference on Biomedical and Health Informatics (BHI)

作者： Hasib, Md Musaddaqul Lybrand, Zane Estevez, Vanesa Nieto Hsieh, Jenny Huang, Yufei Univ Texas San Antonio Dept Elect & Comp Engn San Antonio TX 78249 USA Univ Texas San Antonio Dept Biol San Antonio TX USA

ISBN: (纸本)9781728108483

Three-dimensional brain organoids offer an unprecedented opportunity to study human brain development and disease. Characterizing context-specific organoid behaviors from local field potential (LFP) signals presents many machine learning challenges yet to be adequately addressed. We present in this paper classical machine learning and deep learning solutions to identify the LFP signatures unique to CHD2-mutant hESCs organoids and characterize their changes over time. We showed that a support vector machine (SVM) approach selected five frequency band-power features for 6 and 9-month-old organoids and achieved respective 99.3% and 88.1% area under the curve (AUC) performances in differentiating CHD2-mutant organoids from control using top five band-power features. We also proposed a convolutional neural network (CNN) that successfully classified both month 6 and month 9 CHD2 mutant organoids from controlled organoids using raw LFP signals with AUCs of with 99.6% and 99.7% respectively. We also reconstructed the discriminate features learned by CNN and showed their similarity and uniqueness compared with features selected by SVM.

关键词： hESCs Organoid CHD2 gene multi electrode array local field potential SVM Deep Learning CNN

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