Photoelectrochemical Biosensor Based on 1D InO Tube Decorated with 2D ZnInS Nanosheets for Sensitive PSA Detection.

In photoelectrochemical (PEC) biosensing, efficient electron-hole separation is crucial to obtain preferred photocurrent response and analytical performance; thus, constructing developed heterointerfaces with high carrier transfer efficiency is an effective method for sensitive evaluation of analytes. Herein, a 1D ZnInS nanosheet-decorated 2D InO tube was developed to integrate with a prostate antigen (PSA)-sensitive aptamer for sensitive PSA antigen detection. 1D InO tubes were first prepared by two-step hydrothermal and annealing methods, followed by the in-situ growth of ZnInS nanosheets. Morphology, optical properties, structure, and PEC performance of prepared InO-ZnInS were characterized by scanning electron microscopy, transmission electron microscopy, ultraviolet-visible spectrophotometry, X-ray diffraction, X-ray photoelectron spectroscopy, and an electrochemical workstation. Benefiting from the photoelectric effect and specific 1D/2D hierarchical structure, InO-ZnInS displayed enhanced optical absorption and photocarrier separation, thus a superior photoelectrochemical response. Proposed bioassay protocol possessed a linear range from 0.001 to 50 ng/mL and a detection limit at 0.00037 ng/mL. In addition, this biosensor exhibited satisfactory anti-interface ability and stability, which also could be extended to other quantitative platforms for detecting other proteins.