Fabrication of polyphenol biosensor based on laccase immobilized on copper nanoparticles/chitosan/multiwalled carbon nanotubes/polyaniline-modified gold electrode

A high-performance amperometric polyphenol biosensor was developed, based on covalent immobilization of Ganoderma sp. laccase onto copper nanoparticles (CuNP's)/chitosan (CHIT)/carboxylated multiwalled carbon nanotube (cMWCNT)/polyaniline (PANI)-modified gold (Au) electrode. The CuNP's and cMWCNT had a synergistic electrocatalytic effect in the matrix of CHIT. The biosensor showed optimum response at pH 6.0 (0.1 M acetate buffer) and 35 °C, when operated at 50 mV s⁻¹. The biosensor exhibited excellent sensitivity (the detection limit was down to 0.156 μM for guaiacol), fast response time (less than 4 s) and wide linear range (from 1 to 500 μM). Analytical recovery of added guaiacol was 96.40-98.46%. Within batch and between batch coefficients of variation were <2.6% and <5.3%, respectively. The enzyme electrode was used 300 times over a period of 7 months, when stored at 4 °C.