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micro electrode array

R Perrier, A Pirog, M Jaffredo, J Gaitan, B Catargi, S Renaud, M Raoux, J Lang
On-line and real-time analysis of micro-organ activity permits to use the endogenous analytical power of cellular signal transduction algorithms as biosensors. We have developed here such a sensor using only a few pancreatic endocrine islets and the avoidance of transgenes or chemical probes reduces bias and procures general usage. Nutrient and hormone-induced changes in islet ion fluxes through channels provide the first integrative read-out of micro-organ activity. Using extracellular electrodes we captured this read-out non-invasively as slow potentials which reflect glucose concentration-dependent (3-15 mM) micro-organ activation and coupling...
June 8, 2018: Biosensors & Bioelectronics
Anke M Tukker, Fiona M J Wijnolts, Aart de Groot, Remco H S Westerink
Neurotoxicity testing still relies on ethically debated, expensive and time consuming in vivo experiments, which are unsuitable for high-throughput toxicity screening. There is thus a clear need for a rapid in vitro screening strategy that is preferably based on human-derived neurons to circumvent interspecies translation. Recent availability of commercially obtainable human induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes holds great promise in assisting the transition from the current standard of rat primary cortical cultures to an animal-free alternative...
June 14, 2018: Neurotoxicology
Amine El Kacimi, Emmanuelle Pauliac-Vaujour, Olivier Delléa, Joël Eymery
We report an example of the realization of a flexible capacitive piezoelectric sensor based on the assembly of horizontal c&macr;-polar long Gallium nitride (GaN) wires grown by metal organic vapour phase epitaxy (MOVPE) with the Boostream&reg; technique spreading wires on a moving liquid before their transfer on large areas. The measured signal (<0.6 V) obtained by a punctual compression/release of the device shows a large variability attributed to the dimensions of the wires and their in-plane orientations...
June 12, 2018: Nanomaterials
Jing Ma, Wen Liu, Shuyuan Zhang, Zhe Ma, Peishuai Song, Fuhua Yang, Xiaodong Wang
With high power density, fast charging-discharging speed, and a long cycling life, supercapacitors are a kind of highly developed novel energy-storage device that has shown a growing performance and various unconventional shapes such as flexible, linear-type, stretchable, self-healing, etc. Here, we proposed a rational design of thin film, flexible micro-supercapacitors with in-plane interdigital electrodes, where the electrodes were fabricated using the oblique angle deposition technique to grow oblique Ni/NiO nanowire arrays directly on polyimide film...
June 11, 2018: Nanomaterials
Damion K Corrigan, Vincent Vezza, Holger Schulze, Till T Bachmann, Andrew R Mount, Anthony J Walton, Jonathan G Terry
For analytical applications involving label-free biosensors and multiple measurements, i.e., across an electrode array, it is essential to develop complete sensor systems capable of functionalization and of producing highly consistent responses. To achieve this, a multi-microelectrode device bearing twenty-four equivalent 50 &micro;m diameter Pt disc microelectrodes was designed in an integrated 3-electrode system configuration and then fabricated. Cyclic voltammetry and electrochemical impedance spectroscopy were used for initial electrochemical characterization of the individual working electrodes...
June 9, 2018: Sensors
Catalina Vallejo-Giraldo, Katarzyna Krukiewicz, Ivo Calaresu, Jingyuan Zhu, Matteo Palma, Marc Fernandez-Yague, BenjaminW McDowell, Nathalia Peixoto, Nazar Farid, Gerard O'Connor, Laura Ballerini, Abhay Pandit, Manus Jonathan Paul Biggs
Following implantation, neuroelectrode functionality is susceptible to deterioration via reactive host cell response and glial scar-induced encapsulation. Within the neuroengineering community, there is a consensus that the induction of selective adhesion and regulated cellular interaction at the tissue-electrode interface can significantly enhance device interfacing and functionality in vivo. In particular, topographical modification holds promise for the development of functionalized neural interfaces to mediate initial cell adhesion and the subsequent evolution of gliosis, minimizing the onset of a proinflammatory glial phenotype, to provide long-term stability...
June 3, 2018: Small
Jiří Zemánek, Tomáš Michálek, Zdeněk Hurák
In this paper, we present a novel approach to noncontact micromanipulation by controlled dielectrophoresis (DEP). To steer micro-objects in the desired way, the solutions reported in the literature use either DEP cages or amplitude modulation of the voltages applied to the electrodes. In contrast, we modulate the phases, that is, we control the phase shifts of the voltages applied to the electrodes, which simplifies the hardware implementation and extends the set of feasible forces. Furthermore, we introduce an innovative micro-electrode array layout, composed of four sectors with parallel (colinear) electrodes, which is capable of inducing an arbitrary movement in the manipulation area and is easy to fabricate using just an affordable one-layer technology...
May 24, 2018: Lab on a Chip
Lei Zhang, Nadiia Pasthukova, Yifan Yao, Xiaolan Zhong, Egon Pavlica, Gvido Bratina, Emanuele Orgiu, Paolo Samorì
Self-standing nanostructures are of fundamental interest in materials science and nanoscience and are widely used in (opto-)electronic and photonic devices as well as in micro-electromechanical systems. To date, large-area and self-standing nanoelectrode arrays assembled on flexible substrates have not been reported. Here the fabrication of a hollow nanomesh scaffold on glass and plastic substrates with a large surface area over 1 mm2 and ultralow leakage current density (≈1-10 pA mm-2 @ 2 V) across the empty scaffold is demonstrated...
May 21, 2018: Advanced Materials
Saul Jaime, Jose E Cavazos, Yihong Yang, Hanbing Lu
BACKGROUND: fMRI blood oxygenation level-dependent (BOLD) signal has been widely used as a surrogate for neural activity. However, interpreting differences in BOLD fMRI based on underlying neuronal activity remains a challenge. Concurrent rsMRI data collection and electrophysiological recording in combination with microiontophoretically injected modulatory chemicals allows for improved understanding of the relationship between resting state BOLD and neuronal activity. NEW METHODS: Simultaneous fMRI, multi-channel intracortical electrophysiology and focal pharmacological manipulation data to be acquired longitudinally in rats for up to 2 months...
May 17, 2018: Journal of Neuroscience Methods
Xiao Feng, Benjamin M Bader, Fan Yang, Monica Segura, Luise Schultz, Olaf H-U Schröder, Arndt Rolfs, Jiankai Luo
Niemann-Pick Type C1 (NPC1) disease is an autosomal recessive neurodegenerative disease characterized by an excessive accumulation of unesterified cholesterol in late endosomes/lysosomes. Patients with NPC1 disease show a series of symptoms in neuropathology, including a gradually increased loss of motor control and seizures. However, mechanism of the neurological manifestations in NPC1 disease is not fully understood yet. In this study, we utilized the micro-electrode array (MEA) to analyze the spontaneous extracellular electrical activity in cultivated cortical neurons of the NPC1 mutant (NPC1-/- ) mouse...
May 10, 2018: Brain Research
Viktorija Radotić, Dries Braeken, Petar Drviš, Marta Mattotti, Damir Kovačić
This study investigated micro-patterned, high-density complementary metal-oxide-semiconductor (CMOS) electrode array to be used as biologically permissive environment for organization, guidance and electrical stimulation of spiral ganglion neurons (SGN). SGNs extracted and isolated from cochleae of P5-P7 rat pups and adult guinea pigs were cultured 1, 4 and 7 days in vitro on glass coverslips (control) and CMOS electrode array. The cultures were analyzed visually and immunohistochemically for SGN presence, outgrowth, neurite alignment, neurite length, neurite asymmetry as well as the contact of a neuronal soma and neurites with the micro-electrodes...
May 10, 2018: Scientific Reports
Xin Xi, Dongqing Wu, Lu Han, Yizhen Yu, Yuezeng Su, Wei Tang, Ruili Liu
A soft-hard template-assisted method towards the unconventional free-standing ordered mesoporous carbon sheets (OMCSs) with uniform hexagonal morphology is developed by applying MgAl-layered double hydroxide (MgAl-LDH) as the hard template, triblock copolymer F127 as the soft template and phenolic resols as the carbon sources. It is found that the surface of MgAl-LDH can induce the morphology variation of resol-F127 monomicelles, leading to the formation of vertically or horizontally aligned mesopore arrays in the OMCSs, which can in turn determine their electrochemical energy storage behaviors in supercapacitors with different configuration...
May 7, 2018: ACS Nano
Ziyue Li, Yilin Song, Guihua Xiao, Fei Gao, Shengwei Xu, Mixia Wang, Yu Zhang, Fengru Guo, Jie Liu, Yang Xia, Xinxia Cai
Temporal Lobe Epilepsy (TLE) is a chronic neurological disorder, characterized by sudden, repeated and transient central nervous system dysfunction. For better understanding of TLE, bio-nanomodified microelectrode arrays (MEA) are designed, for the achievement of high-quality simultaneous detection of glutamate signals (Glu) and multi-channel electrophysiological signals including action potentials (spikes) and local field potentials (LFPs). The MEA was fabricated by Micro-Electro-Mechanical System fabrication technology and all recording sites were modified with platinum black nano-particles, the average impedance decreased by nearly 90 times...
April 30, 2018: Analytical Biochemistry
E Josiah Lutton, Wim J E P Lammers, Sean James, Hugo A van den Berg, Andrew M Blanks
KEY POINTS: Coordinated contraction of the uterine smooth muscle is essential to parturition. Histologically and physiologically defined pacemaker structures have not been identified in uterine smooth muscle. Here we report combined electrophysiological and histological evidence of zones associated with pacemaker activity in the rat myometrium. Our method relies crucially on the integration of histological and electrophysiological data in an in silico three-dimensional reconstruction of the rat myometrium at 10 μm resolution...
April 28, 2018: Journal of Physiology
Vera Eßmann, Carla Santana Santos, Tsvetan Tarnev, Mauro Bertotti, Wolfgang Schuhmann
Electrochemical techniques offer high temporal resolution for studying the dynamics of electroactive species at samples of interest. To monitor fastest concentration changes, a micro- or nanoelectrode is accurately positioned in the vicinity of a sample surface. Using a microelectrode array, it is even possible to investigate several sites simultaneously and to obtain an instantaneous image of local dynamics. However, the spatial resolution is limited by the minimal electrode size required in order to contact the electrodes...
May 15, 2018: Analytical Chemistry
Buddha Deka Boruah, Arnab Maji, Abha Misra
An on-chip microsupercapacitor (MSC) pattern is obtained by layer-by-layer spray deposition of both manganese dioxide (MnO2 ) nanoparticle-coated carbon nanotubes (MnO2 -CNTs) and MnO2 nanosheet-decorated reduced graphene oxide (MnO2 -rGO) on mechanically robust, flexible polyethylene terephthalate. Layer-by-layer patterning of MSC electrodes offers rapid in-plane diffusion of electrolyte ions in electrodes the layered electrode and hence ultrahigh capacitance and energy density of 7.43 mF/cm2 (32300 mF/cm3 ) and 0...
May 9, 2018: ACS Applied Materials & Interfaces
Yu Shikano, Takuya Sasaki, Yuji Ikegaya
Monitoring the physiological dynamics of the brain and peripheral tissues is necessary for addressing a number of questions about how the brain controls body functions and internal organ rhythms when animals are exposed to emotional challenges and changes in their living environments. In general experiments, signals from different organs, such as the brain and the heart, are recorded by independent recording systems that require multiple recording devices and different procedures for processing the data files...
April 2, 2018: Journal of Visualized Experiments: JoVE
Daniele Poli, Bruce C Wheeler, Thomas B DeMarse, Gregory J Brewer
OBJECTIVE: Functions ascribed to the hippocampal sub-regions for encoding episodic memories include the separation of activity patterns propagated from the entorhinal cortex (EC) into the dentate gyrus (DG) and pattern completion in CA3 region. Since a direct assessment of these functions is lacking at the level of specific axonal inputs, our goal is to directly measure the separation and completion of distinct axonal inputs in engineered pairs of hippocampal sub-regional circuits. APPROACH: We co-cultured EC-DG, DG-CA3, CA3-CA1 or CA1-EC neurons in a two-chamber PDMS device over a micro-electrode array (MEA60), inter-connected via distinct axons that grow through the micro-tunnels between the compartments...
April 6, 2018: Journal of Neural Engineering
M Kreir, B Van Deuren, S Versweyveld, A De Bondt, I Van den Wyngaert, H Van der Linde, H R Lu, G Teuns, D J Gallacher
Drug-induced seizures contribute to the high attrition rate of pharmaceutical compounds in development. The assessment of drug-induced seizure liability generally occurs in later phases of development using low throughput and intensive in vivo assays. In the present study, we evaluated the potential of an in vitro assay for detecting drug-induced seizure risk compared to evaluation in rats in vivo. We investigated the effects of 8 reference drugs with a known seizurogenic risk using micro-electrode array (MEA) recordings from freshly-dissociated rat primary neurons cultured on 48-well dishes for 28 days, compared to their effects on the EEG in anesthetized rats...
May 1, 2018: Toxicology and Applied Pharmacology
Hongxiu Dai, Duo Chen, Yuan Li, Pengfei Cao, Nan Wang, Meng Lin
An array consisting of homogeneous NiCo2 S4 hollow core-shell nanoneedles was fabricated and is shown to enable sensitive electrochemical determination of dopamine (DA). The array was grown directly on a nickel foam (NF) substrate by a two-step hydrothermal process. The hierarchical nanoarray consists of a homogeneous NiCo2 S4 nanoneedle core and a NiCo2 S4 nanosheet shell. A 3-dimensional micro/nano structure is formed due to the presence of the micropores of the NF. The electrode was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy...
February 5, 2018: Mikrochimica Acta
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