In Vivo Dopamine Biosensor Based on Copper(I) Sulfide Functionalized Reduced Graphene Oxide Decorated Microelectrodes

A novel dopamine biosensor based on carbon fiber microelectrodes (CFMEs) modified with copper(I) sulfide functionalized nanocomposites of the reduced graphene oxide (Cu₂S/RGO) has been explored for the sensitive detection of dopamine and in vivo monitoring the neurotransmitters released by Drosophila's brain. The as-prepared Cu₂S/RGO decorated microelectrodes were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). Our observations demonstrate that Cu₂S/RGO-CFMEs exhibited excellent catalytic activity and high selectivity for dopamine with relatively low detection limit (24 nM), wide linear range (i.e., from 0.1–20 μM) and outstanding reproducibility. Furthermore, the as-prepared new dopamine biosensor with high sensitivity and good stability was readily used to detect the amount of dopamine in the brain of drosophila, indicating the potential and promising application in the in vivo measurement of neurotransmitters without other electrochemical interference such as histidine, ascorbic acid, uric acid, and others.