Open AccessSynaptic Current Response of a Liquid Ga Electrode via a Surface Electrochemical Redox Reaction in a NaOH Solution
Author(s) -
Dahee Seo,
Heejoong Ryou,
Suck Won Hong,
Jong Hyun Seo,
Myunghun Shin,
Wan Sik Hwang
Publication year - 2022
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.2c01645
Subject(s) - electrode , ionic liquid , electrochemistry , neuromorphic engineering , depolarization , materials science , redox , polarization (electrochemistry) , biocompatible material , voltage , chemical engineering , analytical chemistry (journal) , nanotechnology , chemistry , biomedical engineering , biophysics , computer science , chromatography , electrical engineering , catalysis , artificial neural network , organic chemistry , medicine , engineering , machine learning , metallurgy , biology
An ionic device using a liquid Ga electrode in a 1 M NaOH solution is proposed to generate artificial neural spike signals. The oxidation and reduction at the liquid Ga surface were investigated for different bias voltages at 50 °C. When the positive sweep voltage from the starting voltage ( V S ) of 1 V was applied to the Ga electrode, the oxidation current flowed immediately and decreased exponentially with time. The spike and decay current behavior resembled the polarization and depolarization at the influx and extrusion of Ca 2+ in biological synapses. Different average decay times of ∼81 and ∼310 ms were implemented for V S of -2 and -5 V, respectively, to mimic the synaptic responses to short- and long-term plasticity; these decay states can be exploited for application in binary electrochemical memory devices. The oxidation mechanism of liquid Ga was studied. The differences in Ga ion concentration due to V S led to differences in oxidation behavior. Our device is beneficial for the organ cell-machine interface system because liquid Ga is biocompatible and flexible; thus, it can be applied in biocompatible and flexible neuromorphic device development for neuroprosthetics, human cell-machine interface formation, and personal health care monitoring.