Flexible Tongue Electrode Array System for In Vivo Mapping of Electrical Signals of Taste Sensation

AbstractIn this work, we propose a new silicon-based micro-fabrication technology to fabricate 3D high-density high-electrode-count neural micro-probe arrays scalable to thousands and even millions of individual electrodes with user-defined length, width, shape, and tip profile. This unique technology utilizes DRIE of ultra-high aspect-ratio holes in silicon and refilling them with multiple films to form thousands of individual needles with metal tips making up the “sea-of-electrodes” array (SEA). World-record density of 400 electrodes/mm2 in a 5184-needle array is achieved. The needles are ~0.5-1.2mm long, <20μm wide at the base, and <1μm at the tip. The silicon-based structure of these 3D array probes with sharp tips, makes them stiff enough and easily implantable in the brain to reach a targeted region without failing. Moreover, the high aspect ratio of these extremely fine needles reduces the tissue damage and improves the chronic stability. Functionality of the electrodes is investigated using acute in vivo recording in a rat barrel field cortex under isoflurane anesthesia.

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A mm-Sized Free-Floating Wireless Implantable Opto-Electro Stimulation Device

Micromachines ◽

10.3390/mi11060621 ◽

2020 ◽

Vol 11 (6) ◽

pp. 621

Author(s):

Yaoyao Jia ◽

Yan Gong ◽

Arthur Weber ◽

Wen Li ◽

Maysam Ghovanloo

Keyword(s):

Electrical Stimulation ◽

Large Scale ◽

Electrode Array ◽

Cmos Process ◽

Optical Stimulation ◽

In Vivo Experiments ◽

Stimulation Mode ◽

Shift Keying ◽

On Chip

Towards a distributed neural interface, consisting of multiple miniaturized implants, for interfacing with large-scale neuronal ensembles over large brain areas, this paper presents a mm-sized free-floating wirelessly-powered implantable opto-electro stimulation (FF-WIOS2) device equipped with 16-ch optical and 4-ch electrical stimulation for reconfigurable neuromodulation. The FF-WIOS2 is wirelessly powered and controlled through a 3-coil inductive link at 60 MHz. The FF-WIOS2 receives stimulation parameters via on-off keying (OOK) while sending its rectified voltage information to an external headstage for closed-loop power control (CLPC) via load-shift-keying (LSK). The FF-WIOS2 system-on-chip (SoC), fabricated in a 0.35-µm standard CMOS process, employs switched-capacitor-based stimulation (SCS) architecture to provide large instantaneous current needed for surpassing the optical stimulation threshold. The SCS charger charges an off-chip capacitor up to 5 V at 37% efficiency. At the onset of stimulation, the capacitor delivers charge with peak current in 1.7–12 mA range to a micro-LED (µLED) array for optical stimulation or 100–700 μA range to a micro-electrode array (MEA) for biphasic electrical stimulation. Active and passive charge balancing circuits are activated in electrical stimulation mode to ensure stimulation safety. In vivo experiments conducted on three anesthetized rats verified the efficacy of the two stimulation mechanisms. The proposed FF-WIOS2 is potentially a reconfigurable tool for performing untethered neuromodulation.

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Electric Field-Assisted Positioning of Neurons on Pt Microelectrode Arrays

MRS Proceedings ◽

10.1557/proc-773-n4.6 ◽

2003 ◽

Vol 773 ◽

Author(s):

Shalini Prasad ◽

Mo Yang ◽

Xuan Zhang ◽

Yingchun Ni ◽

Vladimir Parpura ◽

...

Keyword(s):

Electric Field ◽

Electrical Activity ◽

Electric Fields ◽

Microelectrode Array ◽

Electrode Array ◽

Sprague Dawley ◽

A Cell ◽

Neuron Patterning

AbstractCharacterization of electrical activity of individual neurons is the fundamental step in understanding the functioning of the nervous system. Single cell electrical activity at various stages of cell development is essential to accurately determine in in-vivo conditions the position of a cell based on the procured electrical activity. Understanding memory formation and development translates to changes in the electrical activity of individual neurons. Hence, there is an enormous need to develop novel ways for isolating and positioning individual neurons over single recording sites. To this end, we used a 3x3 multiple microelectrode array system to spatially arrange neurons by applying a gradient AC field. We characterized the electric field distribution inside our test platform by using two dimensiona l finite element modeling (FEM) and determined the location of neurons over the electrode array. Dielectrophoretic AC fields were utilized to separate the neurons from the glial cells and to position the neurons over the electrodes. The neurons were obtained from 0-2-day-old rat (Sprague-Dawley) pups. The technique of using electric fields to achieve single neuron patterning has implications in neural engineering, elucidating a new and simpler method to develop and study neuronal activity as compared to conventional microelectrode array techniques.

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Intrinsically stretchable electrode array enabled in vivo electrophysiological mapping of atrial fibrillation at cellular resolution

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2000207117 ◽

2020 ◽

Vol 117 (26) ◽

pp. 14769-14778 ◽

Cited By ~ 6

Author(s):

Jia Liu ◽

Xinyuan Zhang ◽

Yuxin Liu ◽

Miguel Rodrigo ◽

Patrick D. Loftus ◽

...

Keyword(s):

Atrial Fibrillation ◽

Spatial Resolution ◽

Electrode Array ◽

Chronic Atrial Fibrillation ◽

Underlying Mechanism ◽

Cellular Level ◽

Definitive Treatment ◽

Comparable Efficacy ◽

Signal Ratio

Electrophysiological mapping of chronic atrial fibrillation (AF) at high throughput and high resolution is critical for understanding its underlying mechanism and guiding definitive treatment such as cardiac ablation, but current electrophysiological tools are limited by either low spatial resolution or electromechanical uncoupling of the beating heart. To overcome this limitation, we herein introduce a scalable method for fabricating a tissue-like, high-density, fully elastic electrode (elastrode) array capable of achieving real-time, stable, cellular level-resolution electrophysiological mapping in vivo. Testing with acute rabbit and porcine models, the device is proven to have robust and intimate tissue coupling while maintaining its chemical, mechanical, and electrical properties during the cardiac cycle. The elastrode array records epicardial atrial signals with comparable efficacy to currently available endocardial-mapping techniques but with 2 times higher atrial-to-ventricular signal ratio and >100 times higher spatial resolution and can reliably identify electrical local heterogeneity within an area of simultaneously identified rotor-like electrical patterns in a porcine model of chronic AF.

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Graphene-based carbon-layered electrode array technology for neural imaging and optogenetic applications

Nature Communications ◽

10.1038/ncomms6258 ◽

2014 ◽

Vol 5 (1) ◽

Cited By ~ 286

Author(s):

Dong-Wook Park ◽

Amelia A. Schendel ◽

Solomon Mikael ◽

Sarah K. Brodnick ◽

Thomas J. Richner ◽

...

Keyword(s):

Soft Tissues ◽

Electrode Array ◽

Electrode Arrays ◽

Neural Imaging ◽

Brain Surface ◽

Array Technology ◽

Micro Electrode Arrays ◽

The Brain

Abstract Neural micro-electrode arrays that are transparent over a broad wavelength spectrum from ultraviolet to infrared could allow for simultaneous electrophysiology and optical imaging, as well as optogenetic modulation of the underlying brain tissue. The long-term biocompatibility and reliability of neural micro-electrodes also require their mechanical flexibility and compliance with soft tissues. Here we present a graphene-based, carbon-layered electrode array (CLEAR) device, which can be implanted on the brain surface in rodents for high-resolution neurophysiological recording. We characterize optical transparency of the device at >90% transmission over the ultraviolet to infrared spectrum and demonstrate its utility through optical interface experiments that use this broad spectrum transparency. These include optogenetic activation of focal cortical areas directly beneath electrodes, in vivo imaging of the cortical vasculature via fluorescence microscopy and 3D optical coherence tomography. This study demonstrates an array of interfacing abilities of the CLEAR device and its utility for neural applications.

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