Amperometric Immunosensor for Prostate Specific Antigen Based on Co‐adsorption of Labeled Antibody and Mediator in Nano‐Au Modified Chitosan Membrane

Abstract

AbstractA quasi‐reagentless amperometric immunosensor for prostate specific antigen (PSA) has been developed based on co‐adsorption of horseradish peroxidase (HRP) labeled PSA antibody (anti‐PSA) and tetramethyl benzidine (TMB) in nano‐Au modified chitosan membrane (Au‐chitosan). The immobilized TMB was used as an electron transfer mediator, which displayed a surface‐controlled process at scan rates less than 45 mV/s, and a diffusion‐controlled process at scan rates higher than 45 mV/s. The immunosensor with the co‐immobilized anti‐PSA and TMB was incubated with sample PSA antigen, and the formed immunoconjugate in the immunosensor was detected by a TMB‐H2O2‐HRP electrochemical system. Under the optimal experimental conditions, PSA could be determined in the linear range from 5.0 to 30 ng·mL−1 with a detection limit of 1.0 ng·mL−1. The prepared PSA immunosensor is not only economic due to the low‐cost ITO electrode obtained from industrial mass production, but also capable of batch fabrication with acceptable detection and storage stability.