Dual signal amplification strategy for enhancing Eu2Sn2O7 electrochemiluminescence immunosensor for the sensitive detection of N-terminal pro-brain natriuretic peptide

Abstract

Pyrochlore oxide Eu2Sn2O7, an electrochemiluminescence (ECL) emitter, exhibits favorable characteristics such as low toxicity, good stability, and abundant electron vacancies. In this work, the interfacial electron transfer efficiency of Eu2Sn2O7 was significantly enhanced through the in situ surface modification with silver nanoparticles (AgNP). Moreover, we introduced a dual signal-amplification strategy involving AgNP and H2O2. The AgNP as a co-reaction catalyst facilitated the reduction of the co-reactant K2S2O8. The OH• generated through H2O2 reduction on the electrode surface induced the decomposition of K2S2O8 to SO4•−. The MoS2-PEI-AuNP (PEI: polyethylenimine) composite was selected as an ideal substrate. A highly sensitive ECL immunosensor based on Eu2Sn2O7-Ag and MoS2-PEI-AuNP was constructed to detect N-terminal pro-brain natriuretic peptide (NT-proBNP). Under the optimized experimental conditions, the ECL immunosensor demonstrated a linear range of 10 fg·mL−1–50 ng·mL−1, with a detection limit of 2.9 fg·mL−1, and showed excellent stability and specificity. The results demonstrate the potential of the ECL immunosensor for clinical diagnosis applications.