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

Abstract

• N 2 H 4 enables CIS@ZnS NCs and [Ru(bpy) 2 (dcbpy)] 2+ for multiplexing ECL in both potential-resolved and color-resolved way. • Baseline separated potential-resolved ECL multiplexing is achieved with CIS@ZnS NCs and [Ru(bpy) 2 (dcbpy)] 2+ as emitters. • Simultaneously determining PSA and CA125 is performed at the pathological cut-off concentration level. 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 ( R s ) is still a great challenge. Herein, a single anodic ECL from two luminophores in the aqueous solution was discriminated completely (baseline separation, R s ≥ 1.5) in a potential-resolved way with the water-soluble CuInS 2 @ZnS (CIS@ZnS) nanocrystals (NCs) and [Ru(bpy) 2 (dcbpy)] 2+ as luminophores and N 2 H 4 as the co-reactant. N 2 H 4 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/N 2 H 4 and [Ru(bpy) 2 (dcbpy)] 2+ /N 2 H 4 could be well defined and distinguished from each other upon potential scanning ( R s = 2.60) and utilized for simultaneously determining human prostate specific antigen and carcinoma antigen 125 at the pathological cut-off concentration ( R s = 1.56).