Ultrasensitive Photoelectrochemical Immunoassay Strategy Based on Bi 2 S 3 /Ag 2 S 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 Bi2 S3 /Ag2 S to realize the sensitive detection of PCT. Bi2 S3 was prepared by a hydrothermal method, and Ag2 S quantum dots were deposited on the ITO/Bi2 S3 surface via in situ reduction. Bi2 S3 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 Bi2 S3 and Ag2 S, a labeled Bi2 S3 /Ag2 S 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-1 to 50 ng∙mL-1 , and the minimum detection limit was 0.18 pg∙mL-1 . 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.