Cathodic electrochemiluminescence behaviour of MoS2 quantum dots and its biosensing of microRNA-21

Abstract

The cathodic electrochemiluminescence (ECL) behaviour of nontoxic MoS₂ quantum dots (QDs) was studied for the first time using potassium peroxydisulfate as the co-reactant. Ag-PAMAM NCs, serving as difunctional tags for quenching and enhancing ECL of MoS₂-reduced graphene oxide composites, were introduced into the ECL detection system for signal amplification. By modulating the interparticle distance between MoS₂ QDs and Ag-PAMAM NCs, the ECL quenching from resonance energy transfer and the ECL enhancement from surface plasma resonance were realized. Coupling the good ECL performance of MoS₂ QDs with the excellent ECL quenching and enhancement effects of Ag-PAMAM NCs, a novel MoS₂ QDs-based ECL biosensing platform for sensitive detection of microRNA-21 was achieved with a detection limit of 0.20 fmol L⁻¹ (S/N = 3). This method was successfully applied to the determination of microRNA-21 in human serum samples with recoveries of 90.0–110.0%, suggesting great potential for its applications in biological and chemical analysis.