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Fabrication of Subretinal 3D Microelectrodes with Hexagonal Arrangement

Title
Fabrication of Subretinal 3D Microelectrodes with Hexagonal Arrangement
Authors
Seo, Hee WonKim, NamjuKim, Sohee
DGIST Authors
Seo, Hee Won; Kim, Namju; Kim, Sohee
Issue Date
2020-05
Citation
Micromachines, 11(5), 467
Type
Article
Article Type
Article
Author Keywords
retinal implantsubretinal stimulation3D electrodeshexagonal electrodestransparent base
Keywords
RETINAL GANGLION-CELLSBLIND SUBJECTSPROSTHESISACTIVATIONBIOCOMPATIBILITYTHRESHOLDS
ISSN
2072-666X
Abstract
This study presents the fabrication of three-dimensional (3D) microelectrodes for subretinal stimulation, to accommodate adjacent return electrodes surrounding a stimulating electrode. For retinal prosthetic devices, the arrangement of return electrodes, the electrode size and spacing should be considered together, to reduce the undesired dissipation of electric currents. Here, we applied the hexagonal arrangement to the microelectrode array for the localized activation of retinal cells and better visual acuity. To provide stimuli more efficiently to non-spiking neurons, a 3D structure was created through a customized pressing process, utilizing the elastic property of the materials used in the fabrication processes. The diameter and pitch of the Pt-coated electrodes were 150 μm and 350 μm, respectively, and the height of the protruded electrodes was around 20 μm. The array consisted of 98 hexagonally arranged electrodes, supported by a flexible and transparent polydimethylsiloxane (PDMS) base, with a thickness of 140 μm. Also, the array was coated with 2 μm-thick parylene-C, except the active electrode sites, for more focused stimulation. Finally, the electrochemical properties of the fabricated microelectrodes were characterized, resulting in the mean impedance of 384.87 kω at 1 kHz and the charge storage capacity (CSC) of 2.83 mC cm-2. The fabricated microelectrodes are to be combined with an integrated circuit (IC) for additional in vitro and in vivo experiments. © 2020 by the authors.
URI
http://hdl.handle.net/20.500.11750/12085
DOI
10.3390/MI11050467
Publisher
MDPI AG
Related Researcher
  • Author Kim, Sohee Neural Interfaces & MicroSystems Lab
  • Research Interests Neural interface; Brain interface; Bio MEMS; Soft MEMS; Stretchable electronics; Zebrafish electrophysiology
Files:
Collection:
Department of Robotics EngineeringNeural Interfaces & MicroSystems Lab1. Journal Articles


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