Using gold nanorods to enhance the current response of a choline biosensor

Abstract This present work describes the utilization of gold nanorods to create a highly responsive choline biosensor. Choline biosensors have been formed with choline oxidase (ChOx) immobilized in composite immobilization membrane matrix, which is composed of Au nanorods and polyvinyl alcohol (PVA) by a sol–gel method. Circular dichroism (CD) shows that the secondary structure of ChOx was preserved after conjugating with Au nanorods. The cyclic voltammograms (CVs) and electrochemical impedance spectroscopy (EIS) give the evidence that gold nanorods can improve the electrical conductivity of PVA-modified enzyme electrode. A set of experimental results indicates that the current response of modified electrode is several times larger than that without nanorods. The experimental conditions of biosensors are optimized, and the performance of the obtained electrodes with respect to linear range, reproducibility, response time, and stability is also presented.