Electroluminescent aptasensor based on RuSiO nanoparticles for detection cytochrome c using ferrocene as quenching probe.

A stable sandwiched electrochemiluminescence (ECL) aptasensor was originally constructed established upon Ru(bpy)-doped silica nanoparticles (RuSiO NPs) with ferrocene carboxylic acid-aptamer (Fc-aptamer) to quantitatively detect cytochrome c (Cyt C). Herein, RuSiO NPs and Fc-aptamer were respectively prepared through the microemulsion method and amide reaction to fabricate the ECL aptasensor. Furthermore, Fc-aptamer was used as quenching probe for quenching the ECL emission of RuSiO NPs. In detail, RuSiO NPs were primarily immobilized onto the electrodes by the film-forming function of chitosan. Subsequently, the aptamer was incubated onto the decorated GCE via crosslinking with glutaraldehyde (GA). After Cyt C was connected to the GCE via immunoreaction, Fc-aptamer was immobilized onto the modified electrodes owing to the specific recognition between antigens and aptamer. Ultimately, ECL signals markedly descended owing to the poor electricity conductivity of proteins and superior quenching effect of Fc-aptamer. Under optimum conditions, the designed ECL aptasensor indicated an accurate analysis for Cyt C in a rang of 0.001-100 nM with a detection limit of 0.48 pM (S/N = 3).