Photoelectrochemical Immunosensor for Sensitive Quantification of Prostate Specific Antigen in Human Serum Samples Exploiting BaTiO3−CdS

Abstract A novel label‐free photoelectrochemical immunosensor was developed for the determination of prostate‐specific antigen (PSA) based on fluorine‐doped tin oxide (FTO) electrode modified with barium titanate and cadmium sulfide (BaTiO 3 −CdS/FTO). The photoelectrochemical current density of the BaTiO 3 platform sensitized with CdS for the ascorbic acid (AA) donor molecule was higher than that observed in the absence of CdS. The BaTiO 3 −CdS/FTO platform was modified with PSA antibodies to produce the anti‐PSA/BaTiO 3 −CdS/FTO immunosensor, which was incubated in solutions of PSA to inhibit the photocurrent density of the immunosensor for AA. The photocurrent density of the anti‐PSA/BaTiO 3 −CdS/FTO immunosensor presented a linear relationship with the logarithm of the PSA concentration ranging from 1 pg mL −1 to 1 μg mL −1 with good sensitivity. The proposed method presented an experimental detection limit of 1 pg mL −1 (S/N=3). The immunosensor was successfully employed for the determination of PSA in blood serum samples, with recoveries between 98.7 %–104.4 %.