Fabrication of Convex PDMS-Parylene Microstructures for Conformal Contact of Planar Micro-Electrode Array

Polymer-based micro-electrode arrays (MEAs) are gaining attention as an essential technology to understand brain connectivity and function in the field of neuroscience. However, polymer based MEAs may have several challenges such as difficulty in performing the etching process, difficulty of micro-p...

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Bibliographic Details
Published in:Polymers 2019-09, Vol.11 (9), p.1436
Main Authors: Lee, Woo Ram, Im, Changkyun, Park, Hae-Yong, Seo, Jong-Mo, Kim, Jun-Min
Format: Article
Language:English
Subjects:
Arrays
Biocompatibility
Contact angle
Electrodes
Entrapment
Epilepsy
Flexibility
Frequencies
Gas flow
Gold
Insulation
Microelectrodes
Molding (process)
Parkinson's disease
Pattern generation
Patterning
Photolithography
Plasma etching
Polymers
Protective coatings
Silicon wafers
Surface energy
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Summary:Polymer-based micro-electrode arrays (MEAs) are gaining attention as an essential technology to understand brain connectivity and function in the field of neuroscience. However, polymer based MEAs may have several challenges such as difficulty in performing the etching process, difficulty of micro-pattern generation through the photolithography process, weak metal adhesion due to low surface energy, and air pocket entrapment over the electrode site. In order to compensate for the challenges, this paper proposes a novel MEA fabrication process that is performed sequentially with (1) silicon mold preparation; (2) PDMS replica molding, and (3) metal patterning and parylene insulation. The MEA fabricated through this process possesses four arms with electrode sites on the convex microstructures protruding about 20 μm from the outermost layer surface. The validity of the convex microstructure implementation is demonstrated through theoretical background. The electrochemical impedance magnitude is 204.4 ± 68.1 kΩ at 1 kHz. The feasibility of the MEA with convex microstructures was confirmed by identifying the oscillation in the beta frequency band (13-30 Hz) in the electrocorticography signal of a rat olfactory bulb during respiration. These results suggest that the MEA with convex microstructures is promising for applying to various neural recording and stimulation studies.
ISSN:2073-4360
2073-4360
DOI:10.3390/polym11091436