An electrochemical approach capable of prostate specific antigen assay in human serum based on exonuclease-aided target recycling amplification

Abstract

In this report, an ultrasensitive electrochemical aptasensor for the detection of prostate specific antigen (PSA) in human serum is presented. DNA tetrahedron molecular layer is designed on the interface of a gold working electrode, which provides the recognition element for PSA capture. Next, exonuclease-aided target recycling amplification is performed, which determines the amount of attached silver nanoparticles (AgNPs) via silver-amino chemistry. By recording electrochemical responses from AgNPs, initial concentration of PSA can be easily evaluated. The limit of detection is pushed down to 0.11pgmL−1, which is attributed to the cyclic digestion effect of exonuclease and highly effective electrochemical reporters of AgNPs. The efficiency and robustness of this approach are further studied using human serum samples. The achieved results are satisfactory for future clinical applications.