micro electrode array

BACKGROUND: Sheep have been proposed as a large-animal model for studying cochlear implantation. However, prior sheep studies report that the facial nerve (FN) obscures the round window membrane (RWM), requiring FN sacrifice or a retrofacial opening to access the middle-ear cavity posterior to the FN for cochlear implantation. We investigated surgical access to the RWM in Hampshire sheep compared to Suffolk-Dorset sheep and the feasibility of Hampshire sheep for cochlear implantation via a facial recess approach...

Although the motor cortex has been found to be modulated by sensory or cognitive sequences, the linkage between multiple movement elements and sequence-related responses is not yet understood. Here, we recorded neuronal activity from the motor cortex with implanted micro-electrode arrays and single electrodes while monkeys performed a double-reach task that was instructed by simultaneously presented memorized cues. We found that there existed a substantial multiplicative component jointly tuned to impending and subsequent reaches during preparation, then the coding mechanism transferred to an additive manner during execution...

Exposure to pesticides, such as carbamates, organophosphates, organochlorines and pyrethroids, has been linked to various health problems, including neurotoxicity. Although most in vivo studies use only male rodents, some studies have shown in vivo sex-specific effects after acute exposure. Since in vivo studies are costly and require a large number of animals, in vitro assays that take sex-specific effects into account are urgently needed. We therefore assessed the acute effects of exposure to different carbamates (methomyl, aldicarb and carbaryl), organophosphates (chlorpyrifos (CPF), chlorpyrifos-oxon (CPO) and 3,5,6-trichloropyridinol), organochlorines (endosulfan, dieldrin and lindane) and pyrethroids (permethrin, alpha-cypermethrin and 3-phenoxy-benzoic acid (3-PBA)) on neuronal network function in sex-separated rat primary cortical cultures using micro-electrode array (MEA) recordings...

Though micro-light-emitting diode (micro-LED) displays are regarded as the next-generation emerging display technology, challenges such as defects in LED's light output power and radiation patterns are critical to the commercialization success. Here we propose an electroluminescence mass detection method to examine the light output quality from the on-wafer LED arrays before they are transferred to the display substrate. The mass detection method consists of two stages. In the first stage, the luminescent image is captured by a camera by mounting an ITO (indium-tin oxide) transparent conducting glass on the LED wafer...

Objective. Neuromodulation, particularly electrical stimulation, necessitates high spatial resolution to achieve artificial vision with high acuity. In epiretinal implants, this is hindered by the undesired activation of distal axons. Here we investigate focal and axonal activation of Retinal Ganglion Cells (RGCs) for different sinusoidal stimulation frequencies. Our results can be exploited to define a selective stimulation strategy to avoid axonal activation in retina implants. Approach. RGC responses to epiretinal sinusoidal stimulation at frequencies between 40 and 100 Hz were tested in ex-vivo photoreceptor degenerated (rd10) retina explants...

Compact high-frequency arrays are of interest for clinical and preclinical applications in which a small-footprint or endoscopic device is needed to reach the target anatomy. However, the fabrication of compact arrays entails the connection of several dozens of small elements to the imaging system through a combination of flexible printed circuit boards at the array end and micro-coaxial cabling to the imaging system. The methods currently used, such as wire bonding, conductive adhesives, or a dry connection to a flexible circuit, considerably increase the array footprint...

Estimating dynamic network communication is attracting increased attention, spurred by rapid advancements in multi-site neural recording technologies and efforts to better understand cognitive processes. Yet, traditional methods, which infer communication from statistical dependencies among distributed neural recordings, face core limitations: they do not model neural interactions in a biologically plausible way, neglect spatial information from the recording setup, and yield predominantly static estimates that cannot capture rapid changes in the brain...

Spreading depolarizations (SDs) are widely recognized as a major contributor to the progression of tissue damage from ischemic stroke even if blood flow can be restored. They are characterized by negative intracortical waveforms of up to -20 mV, propagation velocities of 3 - 6 mm/min, and massive disturbance of membrane ion homeostasis. High-density, micro-electrocorticographic (μECoG) epidural electrodes and custom, DC-coupled, multiplexed amplifiers, were used to continuously characterize and monitor SD and µECoG cortical signal evolution in awake, moving rats over days...

Background: Precise and dynamic blood glucose regulation is paramount for both diagnosing and managing diabetes. Continuous glucose monitoring (CGM) coupled with insulin pumps forms an artificial pancreas, enabling closed-loop control of blood glucose levels. Indeed, this integration necessitates advanced micro-nano fabrication techniques to miniaturize and combine sensing and delivery modules on a single electrode. While microneedle technology can mitigate discomfort, concerns remain regarding infection risk and potential sensitivity limitations due to their short needle length...

The delicate "Excitatory/Inhibitory balance" between neurons holds significance in neurodegenerative and neurodevelopmental diseases. With the ultimate goal of creating a faithful in vitro model of the human brain, in this study, we investigated the critical factor of heterogeneity, focusing on the interplay between excitatory glutamatergic (E) and inhibitory GABAergic (I) neurons in neural networks. We used high-density Micro-Electrode Arrays (MEA) with 2304 recording electrodes to investigate two neuronal culture configurations: 100% glutamatergic (100E) and 75% glutamatergic / 25% GABAergic (75E25I) neurons...

Electroporation (in which the permeability of a cell membrane is increased transiently by exposure to an appropriate electric field) has exhibited great potential of becoming an alternative to adeno-associated virus (AAV)-based retina gene delivery. Electroporation eliminates the safety concerns of employing exogenous viruses and exceeds the limit of AAV cargo size. Unfortunately, several concerns ( e.g. , relatively high electroporation voltage, poor surgical operability and a lack of spatial selectivity of retina tissue) have prevented electroporation from being approved for clinical application (or even clinical trials)...

The undesirable dendrite growth induced by non-planar zinc (Zn) deposition and low Coulombic efficiency resulting from severe side reactions have been long-standing challenges for metallic Zn anodes and substantially impede the practical application of rechargeable aqueous Zn metal batteries (ZMBs). Herein, we present a strategy for achieving a high-rate and long-cycle-life Zn metal anode by patterning Zn foil surfaces and endowing a Zn-Indium (Zn-In) interface in the microchannels. The accumulation of electrons in the microchannel and the zincophilicity of the Zn-In interface promote preferential heteroepitaxial Zn deposition in the microchannel region and enhance the tolerance of the electrode at high current densities...

In this work, we propose porous fluororubber/thermoplastic urethane nanocomposites ( PFTNs ) and explore their intrinsic piezoresistive sensitivity to pressure. Our experiments reveal that the intrinsic sensitivity of the PFTN-based sensor to pressure up to 10 kPa increases up to 900% compared to the porous thermoplastic urethane nanocomposite ( PTN ) counterpart and up to 275% compared to the porous fluororubber nanocomposite ( PFN ) counterpart. For pressures exceeding 10 kPa, the resistance-pressure relationship of PFTN follows a logarithmic function, and the sensitivity is 221% and 125% higher than that of PTN and PFN, respectively...

Structured passivation layers and hydrated Zn2+ solvation structure strongly influence Zn depositions on Zn electrodes and then the cycle life and electrochemical performance of aqueous zinc ion batteries. To achieve these, the electrolyte additive of sodium L-ascorbate (Ass) is introduced into aqueous zinc sulfate (ZnSO4 , ZS) electrolyte solutions. Combined experimental characterizations with theoretical calculations, the unique passivation layers with vertical arrayed micro-nano structure are clearly observed, as well as the hydrated Zn2+ solvation structure is changed by replacing two ligand water molecules with As- , thus regulating the wettability and interfacial electric field intensity of Zn surfaces, facilitating rapid ionic diffusions within electrolytes and electrodes together with the inhibited side reactions and uniform depositions of Zn2+ ...

This paper presents an innovative approach to wireless cellular stimulation therapy through the design of a magnetoelectric (ME) microdevice. Traditional electrophysiological stimulation techniques for neural and deep brain stimulation face limitations due to their reliance on electronics, electrode arrays, or the complexity of magnetic induction. In contrast, the proposed ME microdevice offers a self-contained, controllable, battery-free, and electronics-free alternative, holding promise for targeted precise stimulation of biological cells and tissues...

Large-scale brain activity mapping is important for understanding the neural basis of behaviour. Electrocorticograms (ECoGs) have high spatiotemporal resolution, bandwidth, and signal quality. However, the invasiveness and surgical risks of electrode array implantation limit its application scope. We developed an ultrathin, flexible shape-changing electrode array (SCEA) for large-scale ECoG mapping with minimal invasiveness. SCEAs were inserted into cortical surfaces in compressed states through small openings in the skull or dura and fully expanded to cover large cortical areas...

Submillimeter or micrometer scale electrically controlled soft actuators have immense potential in microrobotics, haptics, and biomedical applications. However, the fabrication of miniaturized and micropatterned open-air soft actuators has remained challenging. In this study, we demonstrate the microfabrication of trilayer electrochemical actuators (ECAs) through aerosol jet printing (AJP), a rapid prototyping method with a 10 μm lateral resolution. We make fully printed 1000 × 5000 × 12 μm3 ultrathin ECAs, each of which comprises a Nafion electrolyte layer sandwiched between two poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) electrode layers...

The vagus nerve (VN) plays an important role in regulating physiological conditions in the gastrointestinal (GI) tract by communicating via the parasympathetic pathway to the enteric nervous system (ENS). However, the lack of knowledge in the neurophysiology of the VN and GI tract limits the development of advanced treatments for autonomic dysfunctions related to the VN. To better understand the complicated underlying mechanisms of the VN-GI tract neurophysiology, it is necessary to use an advanced device enabled by microfabrication technologies...

Protein preconcentration is an essential sample preparation step for analysis in which the targeted proteins exist in low concentrations, such as bodily fluids, water, or wastewater. Nonetheless, very few practical implementations of miniaturized protein preconcentration devices have been demonstrated in practice, and even fewer have been integrated with other microanalytical steps. Existing approaches rely heavily on additional chemicals and reagents and introduce complexity to the overall assay. In this paper, we propose a novel miniaturized isoelectric focusing-based protein preconcentration screening device based on electrochemically derived pH gradients rather than existing chemical reagent approaches...

Dielectrophoresis (DEP) utilizes a spatially varying nonuniform electrical field to induce forces on suspended polarizable soft matter including particles and cells. Such nonuniformities are conventionally created using 2D or 3D micrometer-scale electrode arrays. Alternatively, insulator-based dielectrophoresis (iDEP) uses small micrometer-scale insulating structures to spatially distort and generate regions of localized field gradients to selectively trap, isolate, and concentrate bioparticles, including bacteria, viruses, red blood cells, and cancer cells from a suspending electrolyte solution...