An electrochemical immunosensor based on a multiple signal amplification strategy for highly sensitive detection of prostate specific antigen

Abstract

A sandwich-type electrochemical immunosensor was developed based on a multiple signal amplification strategy. To enable this objective, pompon-like palladium@platinum nanoparticles were attached onto a 3-aminopropyl-triethoxysilane functionalized cuprous oxide@cobalt oxide nanocomposite (Pd@Pt-APTES-Cu₂O@Co₃O₄) by constructing Pt–N bonds. The nanocomposite exhibited better electrocatalytic activity towards the reduction of hydrogen peroxide than each component and was used as a multiple signal amplification label to capture secondary antibodies due to its splendid electrochemical performance. Meanwhile, a gold nanoparticle incorporated chitosan-graphene nanocomposite solution (Au-CS-Gr) was modified on a glassy carbon electrode and employed as an electron transfer facilitator and primary antibody carrier. The proposed electrochemical immunosensor showed a wide linear range from 0.01 pg mL⁻¹ to 100 ng mL⁻¹ and a low detection limit of 2.0 fg mL⁻¹ for quantitative detection of PSA. It also exhibited high sensitivity, good stability and acceptable reproducibility. Furthermore, a favorable result was obtained when the proposed method was applied to the analysis of human serum samples, which indicated its potential application in clinical analysis of tumor markers.