RuSi@Ru(bpy)32+/Au@Ag2S Nanoparticles Electrochemiluminescence Resonance Energy Transfer System for Sensitive DNA Detection

This work describes a new electrochemiluminescence resonance energy transfer (ECL-RET) system with graphene oxide(GO)–Au/RuSi@Ru(bpy)32+/chitosan (CS) composites as the ECL donor and Au@Ag2S nanoparticles (NPs) as ECL the acceptor for the first time. The ECL signal observed by the application of GO–Au/RuSi@Ru(bpy)32+/CS composites was enhanced for 5-fold compared to that of RuSi@Ru(bpy)32+/CS in the presence of coreactant tripropylamine (TPA) due to the increased surface area and improved electrical conductivity by using graphene oxide–gold nanoparticles (GO–Au) composite materials. In addition, we synthesized Au@Ag2S core–shell NPs, whose UV–vis absorption spectrum shows good spectral overlap with the ECL spectrum of GO–Au/RuSi@Ru(bpy)32+/CS composites by adjusting the amount of Na2S and AgNO3 in the process of synthesis. The distance between energy donor and acceptor was studied to get the highly effective ECL-RET. Then, this ECL-RET system was developed for sensitive and specific detection of target DNA, and the ECL quenching efficiency (ΔI/I0, ΔI = I0 – I) was found to be logarithmically related to the concentration of the target DNA in the range from 10 aM to 10 pM.