Ultrasensitive Photoelectrochemical Immunoassay Strategy Based on BiS/AgS for the Detection of the Inflammation Marker Procalcitonin.

As an inflammatory marker, procalcitonin (PCT) is more representative than other traditional inflammatory markers. In this work, a highly efficient photoelectrochemical (PEC) immunosensor was constructed based on the photoactive material BiS/AgS to realize the sensitive detection of PCT. BiS was prepared by a hydrothermal method, and AgS quantum dots were deposited on the ITO/BiS surface via in situ reduction. BiS is a kind of admirable photoelectric semiconductor nanomaterial on account of its moderate bandgap width and low binding rate of photogenerated electron holes, which can effectively convert light energy into electrical energy. Therefore, based on the energy level matching principle of BiS and AgS, a labeled BiS/AgS PEC immunosensor was constructed, and the sensitive detection of PCT was successfully established. The linear detection range of the PEC immunosensor was 0.50 pg∙mL to 50 ng∙mL, and the minimum detection limit was 0.18 pg∙mL. Compared with the traditional PEC strategy, the proposed PEC immunosensor is simple, convenient, and has good anti-interference, sensitivity, and specificity, which could provide a meaningful theoretical basis and reference value for the clinical detection of PCT.