?Signal-on? molecularly imprinting-aptamer electrochemiluminescence platform for ultrasensitive detection of thrombin

A novel ?signal-on? molecular imprinting-aptamer electrochemiluminescence (ECL) platform is designed for ultrasensitive bioanalysis of thrombin (TB) based on the SiO2 loaded with Ru(bpy)32+/polyetherimide-graphene oxide (RuNP/PEI-GO) nanocomposite as signal labels. Specifically, ?signal-on? ECL sensing strategy and molecular imprinting technology is combined together to fabricate sensing platform. The nanocavity corresponding to TB produced by molecular imprinting can be used for multiple specific recognition of TB together with aptamers. Moreover, high-quality ECL nanocomposite luminophore is achieved by means of RuNP/PEI-GO nanocomposite with significant ECL efficiency and stability. Simultaneously, PEI, as a co-reaction, can shorten the electron-transfer path of this ECL system to reduce the energy loss, resulting in the enhancement of ECL signal effectively. ECL signal strength of RuNP/PEI-GO is about 7 times higher than that of RuNP due to the synergy effect of PEI, GO and RuNP, thus further expanding the detection range of TB. This ECL sensing platform for TB detection shows satisfactory sensitivity with a low detection limit of 28.73 fM in the concentration range from 10-13 M to 10-8 M. This developed ?signal-on? ECL platform with RuNP/PEI-GO nanocomposite is expected to become a promising tool for detecting other biomarkers in the future.