An electrochemical aptasensor based on synergistic effect of duplex-specific nuclease and nanoporous gold for ultrasensitive detection of prostate-specific antigen.

Prostate cancer (PCa), the most common solid tumor in men, is typically suspected based on digital rectal examination and elevated serum prostate-specific antigen (PSA) levels. Given its clinical significance, developing a PSA biosensing system with high sensitivity and stability is essential. In this study, a novel aptasensor, leveraging the synergistic effect of duplex specific nuclease (DSN) and nanoporous gold (NP-Gold), was firstly developed for PSA detection. The aptamer, which hybridizes with its complementary DNA to form double-stranded DNA (dsDNA), was used as biorecognition element. NP-Gold served as the supporting material. By exploiting the large specific surface area and high conductivity of NP-Gold, the immobilized amount of dsDNA was increased, thereby expanding the dynamic detection range of PSA. DSN can recognize and cleave non-PSA-bound dsDNA. By reducing noise signals derived from such unbound dsDNA, it enhances the correlation between electrical signals and PSA concentration, ultimately lowering the detection limit. Benefiting from the synergistic effect of DSN and NP-Gold, the developed aptasensor showed a wide linear relationship between current values and PSA concentrations, with a detection range from 100 fg/mL to 10 ng/mL and a limit of detection (LOD) of 2.7 fg/mL. Moreover, the aptasensor demonstrated excellent resistance to interference from various proteins and retained 96 % of its current response after 21 days of storage. Additionally, the proposed aptasensor successfully detected PSA concentrations in real human serum samples, with accuracy comparable to that of the ELISA kit. These distinctive characteristics made the aptasensor a reliable choice for PSA detection and early diagnosis of PCa.