SnO2 quantum dots functionalized 3D graphene composite for enhanced performance of electrochemical myoglobin biosensor

Abstract

In this work, we reported on the electrochemical behaviors and electrocatalysis of myoglobin (Mb) biosensor based on SnO2 quantum dots functionalized three-dimensional graphene composite (SnO2-QDs@3DGR) modified carbon ionic liquid electrode (CILE). The SnO2-QDs@3DGR composite was synthesized via a facile one-step hydrothermal strategy, which offered rich channels, enough active sites, high conductivity and good biocompatibility for bonding with Mb. The direct electron transfer (DET) performance between Mb and SnO2-QDs@3DGR modified electrode was greatly improved with electrochemical responses increased. In cyclic voltammetric investigation, a pair of well-defined redox peaks of Mb were observed with the formal peak potential of-0.263 V (E0') and a peak-to-peak separation of 75 mV (ΔEp). The heterogeneous electron transfer constant (ks) was calculated as 1.34 s-1. Furthermore, the modified electrode with chitosan (CTS) film (CTS/Mb/SnO2-QDs@3DGR/CILE) was used for the electrocatalysis of trichloroacetic acid, which showed a wider linear response from 5.0 to 94.0 mmol L-1 with the limit of detection as 0.35 mmol L-1.