Highly potential-resolved anodic electrochemiluminescence multiplexing immunoassay with CuInS2@ZnS nanocrystals and [Ru(bpy)2(dcbpy)]2+ as emitters

Abstract Discriminating the electrochemiluminescence (ECL) of differed luminophores is crucial for ECL multiplexing. However, because of the limited potential window for ECL assay and the overlapped triggering-potential-range between different luminophores, the potential-resolved ECL multiplexing with good resolutions (Rs) is still a great challenge. Herein, a single anodic ECL from two luminophores in the aqueous solution was discriminated completely (baseline separation, Rs≥1.5) in a potential-resolved way with the water-soluble CuInS2@ZnS (CIS@ZnS) nanocrystals (NCs) and [Ru(bpy)2(dcbpy)]2+ as luminophores and N2H4 as the co-reactant. N2H4 could be electrochemically oxidized to reducing radicals and then reacted with the electrochemically oxidized CIS@ZnS NCs and [Ru(bpy)2(dcbpy)]2+ in sequence to produce co-reactant ECL. The potential-resolved ECL of CIS@ZnS NCs/N2H4 and [Ru(bpy)2(dcbpy)]2+/N2H4 could be well defined and distinguished from each other upon potential scanning (Rs=2.60) and utilized for simultaneously determining human prostate specific antigen and carcinoma antigen 125 at the pathological cut-off concentration (Rs=1.56).