The construction of electrochemical aptasensor based on coral-like polyaniline and Au nano-particles for the sensitive detection of prostate specific antigen

Prostate specific antigen (PSA), as the significant biomarker of prostate cancer, has aroused widespread concern. However, constructing the PSA aptasensor with high sensitivity and low detection limit is still facing huge challenges. In this study, a sensitive electrochemical aptasensor for detecting PSA based on coral-like polyaniline (PANI)/gold nano-particles (AuNPs) and the peptides was constructed. Coral-like PANI and AuNPs with the diameter of 50-80 nm, as the substrate materials, were directly deposited on glass carbon electrode (GCE) by electrodeposited method. Then, the peptides, as the antifouling materials, were anchored on the modified-electrode, which not only can form antifouling surface to reduce nonspecific adsorption, but also can be as a medium between the modified-electrode and PSA aptamer. Finally, the PSA aptamer was immobilized on the electrode. Based on the synergistic effect of excellent conductivity and special morphology of the substrate materials, and the antifouling ability of peptides, the aptasensor exhibited a high sensitivity of 462.7 mu A(ng mL(-1))(-1) cm(-2), wide linear range from 0.1 pg mL(-1) to 100 ng mL(-1), low limit of detection (LOD) of 0.085 pg mL(-1) and good antifouling performance. The aptasensor also possessed outstanding selectivity, reproducibility and stability. Moreover, the aptasensor can directly detect PSA in 10% human serum solutions.