Design of Novel Biosensors for Determination of Phenolic Compounds using Catalyst-Loaded Reduced Graphene Oxide Electrodes

Abstract

Facile and inexpensive method for designing high performance sensors for H2O2 and polyphenols has been developed. The proposed sensors are based on high electrocatalytic activity of Prussian Blue (PB) nanoparticles deposited in situ on high surface area graphene nanosheet-based thin films on a graphite electrode. The exfoliated graphene nanosheets were formed by attaching graphene oxide to the electrode surface followed by their electrochemical reduction to obtain the reduced graphene oxide (rGO), providing high surface area and excellent current-carrying capabilities to the sensory film. The PB catalyst nanoparticles were deposited electrochemically on rGO. This procedure is very time efficient as it reduces the time of sensor preparation from 3 days (according to recent literature) to several hours. The proposed method provides simple means to obtain highly reliable and stable sensory films. The sensor shows a dynamic range of 1–500 μM H2O2 and a rapid response of 5 s to reach 95% of a steady-state response. When combined with immobilized enzymes (horseradish peroxidase or laccase oxidase), it can serve as a biosensor for polyphenols. As the proof of concept, the response of the enzymatic biosensors to polyphenol catechin has been presented delineating different mechanisms of horseradish peroxidase and laccase operation. The proposed sensors are low cost, reliable, and scalable.