Choline Biosensor Based on Poly(thionine)/H2O2 Photoelectrochemical Sensing Interface

A novel choline biosensor based on the chitosan-immobilized choline oxidase on a poly(thionine)-modified ITO electrode (PThE) is described in this article. In this study, the photosensitive PThE was employed as an electron acceptor, and H2O2 produced by the catalytic reaction was employed as an electron donor, developing a photoelectrochemical choline biosensor. The photoelectrochemical responses of biosensor to H2O2 and choline were studied. The effects of bias voltage, light intensity and pH of electrolyte on photocurrent were investigated. The linear response of choline concentrations ranging from 0.05 to 2.00 mM was obtained with a detection limit of 30.0 μM and a sensitivity of 65.7 μA M−1. The applied feasibility of biosensor was acknowledged by monitoring the phosphatidylcholine in lecithin samples. The prepared biosensor is economical, rapid, simple and convenient to detect the choline without hydrogen peroxidase.