β-Cyclodextrin inclusion complex as the immobilization matrix for laccase in the fabrication of a biosensor for dopamine determination

摘要

Inclusion complex of β-cydodextrin (β-CD) and benzaldehyde (BA) was synthesized to immobilize laccase (Lac) in this paper. The obtained CDBA-Lac complex was further generated onto reduced graphene oxide (rGO) modified screen-printed carbon electrodes (SPEs) through an electropolymerization process. In the fabricated Lac-based biosensor, β-CD provided a biocompatible microenvironment for Lac to retain its bioactivity and rGO possessed excellent conductivity to enhance the electron transfer rate. The electrochemical behavior of dopamine (DA) on the modified electrode was investigated with cyclic voltammetry and differential pulse voltammetry. A remarkable anti-interference performance for detection of DA in the presence of 0.1 mM ascorbic acid was achieved at this biosensor. DA peak current is linear with the concentration of DA in the range of 0.1-70 μM, with a low detection limit of 0.03 μM (S/N=3). Finally, this proposed biosensor was successfully employed to the detection of DA in human urine samples with satisfactory results. These findings suggest that this novel biosensor could be a promising tool for many routine sensing applications.