An ultrasensitive electrochemiluminescence sensor based on luminol functionalized AuNPs@Fe-Co-Co nanocomposite as signal probe for glutathione determination

Abstract In this work, the FeyCo3-y [Co (CN)6]2 Prussian blue analogues (Fe-Co-Co PBAs) was first used as the regenerable co-reaction accelerator in luminol-O2 system to accelerate the electrochemiluminescence (ECL) reaction rate of luminol and the co-reactant of O2 for signal amplification. Remarkably, the ECL intensity of luminol functionalized AuNPs@Fe-Co-Co (luminol-AuNPs@Fe-Co-Co) nanocomposite first synthesized as an ECL probe via a green and simple method exhibited ~41-fold enhancement compared with luminol-AuNPs. Because the Fe-Co-Co PBAs with excellent reversible redox property could accelerate the reduction of dissolved O2 to generate plenty of reactive oxygen species (ROSs) for promoting luminol to emit a strong ECL signal. In addition, Fe-Co-Co PBAs acted as a satisfying nanocarrier to immobilize more luminol-AuNPs. Owing to the strong quenching effect of glutathione (GSH) on the ECL emission of luminol, the constructed ECL sensor for the quantitative analysis of GSH performed an excellent linearity from 1.0 nM to 1.0 mM with a low detection limit of 0.11 nM. Simultaneously, the proposed sensor applied for GSH determination in human serum samples with desirable results. This work introduced a robust co-reaction accelerator into luminol-O2 system to enhance the ECL intensity, further widening the application of luminol-centric ECL sensor in the bioanalysis field.