Anodic self-enhanced Ru@Zn-MOF and double quencher MnO2@AuNPs for the detection of SCCA

In this study, Ru(bpy) 3 2+ and oxalate (C 2 O 4 2− ) in Ru@Zn-MOF generated self-enhanced electrochemiluminescence (ECL). The self-enhanced ECL composite exhibited a short electron transfer distance and minimal energy loss, which ensured the high and stable luminescence efficiency of Ru@Zn-MOF. A MnO 2 @AuNPs nanocomposite was introduced into Ru@Zn-MOF via antigen–antibody interactions in the presence of squamous cell carcinoma antigen (SCCA). This significantly quenched the ECL signal due to the combined effect of the dual quenchers, MnO 2 NFs and AuNPs. A highly efficient ECL-RET immunosensor was constructed for the sensitive detection of SCCA in the linear range of 1 fg/mL to 100 ng/mL, with a limit of detection of 0.26 fg/mL (S/N = 3). This immunosensor has broad clinical applications for the quantitative detection of biomarkers.