A dual-signal electrochemiluminescence immunosensor for high-sensitivity detection of acute myocardial infarction biomarker

Based on two different types of luminescence systems (Ru﹡(bpy)32+/TPA and SnO2 NFs/K2S2O8), a new type of electrochemiluminescence (ECL) immunosensor was prepared, which realized the detection of acute myocardial infarction biomarker cTnI. In this strategy, Ru(bpy)32+, above all, was immobilized on the NH2-MIL-125 as a capture probe. Subsequently, cTnI and SnO2 NFs was bonded to the electrode surface through the interaction between antigen and antibody in turn. During this process, Ru(bpy)32+ and the co-reactant TPA first showed strong and stable ECL emission. As the concentration of cTnI in the test system increased, the signal of SnO2 NFs and the co-reactant K2S2O8 gradually enhanced, indicating self-calibrating mechanism of the assay system. Therefore, the "off-on" ECL immunosensor can be detected in the linear range of 10-5 -104 ng/mL, and the limit of detection (LOD) is 3.39 fg/mL (S/N = 3), respectively. The dual-signal electrochemiluminescence method has the advantages of low cost, simple analysis process, wide detection range and good selectivity, providing a promising analysis protocol for clinical applications.