Development of a screen-printed electrochemical immunosensor modified with gold nanoparticles for prostate-specific antigen (PSA) detection

In this study, an electrochemical immunosensor was developed using as a bare electrode, a homemade polyethylene terephthalate (PET) substrate silkscreen-printed with graphite-based ink, carbon black, and nail polish. The electrode was modified with gold nanoparticles, antibodies, and bovine serum albumin (BSA) for the detection and quantification of the PSA biomarker in serum samples. The analytical response was monitored by the electrochemical behavior of the potassium ferrocyanide redox probe when adding each modification to the electrode surface. The parameters optimized for the best performance of the immunosensor were antibody incubation time (30 min), BSA (30 min), antigen (10 min), pH, and concentration of the supporting electrolyte (pH 7.0, 0.1 mol L−1). The immunosensor proposed for PSA detection had a LOD of 0.55 ng mL−1 and a LOQ of 1.08 ng mL−1. Selectivity studies in the presence of other macromolecules showed minimal interference with RSD of 5.0