Signal–off electrochemiluminescence immunosensor based on AgS quantum dots quenching luminol modified Ag/Cu2O/Ti3C2 nanocomposites for h–FABP detection

This study successfully developed a highly sensitive electrochemiluminescence (ECL) sensor based on the ECL resonance energy transfer mechanism for detecting the key biomarker of acute myocardial infarction, heart–type fatty acid binding protein (h–FABP). Through the meticulous design of the Ag/Cu2O/Ti3C2 ternary nanocomposite material, this material demonstrated significant catalase–like catalytic activity, enabling the efficient decomposition of H2O2 to generate more superoxide radicals (O₂•⁻), thereby significantly enhancing the ECL signal of the luminol–H2O2 system. Notably, AgS quantum dots (AgS QDs), due to broad–spectrum ultraviolet absorption overlapping with the ECL emission spectrum of luminol, triggered an efficient energy resonance transfer effect, resulting in the decrease of ECL intensity. NH2–MIL–101(Fe) was utilized to couple with AgS QDs (AgS QDs@NH2–MIL–101(Fe)), which can further enhance the quenching efficiency. Based on this signal–off strategy, an ultrasensitive detection platform for h–FABP was successfully constructed. Experimental results indicated that the immunosensor exhibited an excellent response relationship within a wide linear range from 1.00 fg mL–1 to 100 ng mL–1, and a low detection limit reached 0.36 fg mL–1 (S/N = 3). This study provides an innovative methodological approach for ultra–trace detection of myocardial injury markers and demonstrates significant application potential in early clinical diagnosis.