A prostate-specific antigen electrochemical immunosensor based on Pd NPs functionalized electroactive Co-MOF signal amplification strategy.

A sandwich-type electrochemical immunosensor for prostate-specific antigen (PSA) detection was constructed. In this sensing platform, palladium nanoparticles (Pd NPs) loaded electroactive amino-zeolitic imidazolate framework-67 (Pd/NH2-ZIF-67) nanocomposite is utilized as a novel redox mediator. Pd NPs, as the labeling signal molecule, owns good biocompatibility and excellent catalytic performance. Meanwhile, the electroactive ZIF-67 with lamellar structures serves not only as a carrier of Pd NPs but also as a synergistic catalyst of palladium to decompose H2O2. Amperometric method is used to determine the current signal generated on the electrode surface, which is conducive to achieve the quantitative determination of PSA. Under optimum conditions, the proposed immunosensor shows a wide detection range from 100 fg mL-1 to 50 ng mL-1 with a low detection limit of 0.03 pg mL-1, featuring favorable selectivity, repeatability and stability. This proposed immunosensor is expected to be a powerful tool for realizing quantitative detection of PSA and other biomarkers in actural sample analysis.