A novel photoelectrochemical sensor for the detection of α-fetoprotein based on a mesoporous TiO2–CdS QD composite film

Abstract

In this article, a label-free photoelectrochemical immunosensor based on a CdS-modified mesoporous TiO₂ film has been developed. The CdS quantum dots could be deposited onto the mesoporous TiO₂ film by electrochemical deposition, which could enhance the photocurrent intensity in the visible region. Employing specific binding of antigen–antibody, α-fetoprotein (AFP) could be captured on the surface of the modified electrode. Based on the steric hindrances, the photocurrent intensity decreased with the increase in AFP concentration. A linear response from 0.05 ng mL⁻¹ to 20 ng mL⁻¹ was obtained for AFP detection and the detection limit was 0.02 ng mL⁻¹. Moreover, the practical determination of AFP in human serum was also investigated.