An electrochemiluminescence immunosensor with double co-reaction accelerators based on Ag3PO4@EuPO4-AgNP for detecting squamous cell carcinoma antigen.

Abstract

This study aimed to design a sandwich electrochemiluminescence (ECL) immunosensor with double co-reaction accelerators for sensitively detecting squamous cell carcinoma antigen (SCCA). First, silver orthophosphate (Ag3PO4) nanoparticles were modified on the surface of EuPO4 nanowires to improve their poor dispersibility/solubility. At the same time, EuPO4 was used as a co-reaction accelerator to catalyze S2O82- to produce more intermediates (SO4•-), significantly enhancing the ECL signal of Ag3PO4. Ag nanoparticles (AgNP) modified on Ag3PO4@EuPO4 composite nanomaterials were used not only as linkers of luminescence groups and biomarkers but also as a co-reaction accelerator to effectively enhance ECL signal. The designed ECL immunosensor displayed several advantages, including good stability and reproducibility. Under the optimal conditions, its linear range in detecting SCCA was 0.0001-50ng·mL-1, the detection limit was 25fg·mL-1 (S/N = 3), the recovery was 96.6-100.4%, and the relative standard deviation was less than 4.8%. It was successfully applied todetect SCCA in human serum.