A novel signal-on junction-probe electrogenerated chemiluminescence (ECL) aptamer biosensor has been developed for the detection of ultratrace thrombin based on a structure-switching ECL-quenching mechanism. The ECL aptamer biosensor comprises two main parts: an ECL substrate and an ECL intensity switch. The ECL substrate was made by modifying the complex of Au nanoparticle and ruthenium (II) tris-bipyridine (Ru(bpy)32+-AuNPs) on the surface of gold electrode (GE), and the ECL intensity switch contains three probes designed according to the " junction-probe" strategy. The first probe is capture probe (Cp) which was functionalized with a thiol group at one end and covalently attached to Ru(bpy)32+-AuNPs modified GE through S-Au bonding. The second probe is aptamer probe (Ap), which containing 15-base anti-thrombin DNA aptamer. The third one is ferrocene-labeled probe (Fp), which was functionalized with ferrocene tag at one end. We demonstrated that, in the absence of thrombin, Cp, Ap and Fp will hybridize to form a ternary " Y" junction structure and resulted in a quenching of ECL of Ru(bpy)32+. Whereas, in the presence of thrombin, the Ap prefers to form the G-quadruplex aptamer-thrombin complex and lead to an obvious recovery of ECL of Ru(bpy)32+, which provided a sensing platform for the detection of thrombin. Using this reusable sensing platform, a simple, rapid and selective signal-on ECL aptamer biosensor for the detection of thrombin with a detection limit of 8.0×10-15M has been developed. The success in the present biosensor served as a significant step towards the development of monitoring ultratrace thrombin in clinical detection. © 2010 Elsevier B.V.
Zhang, J., Chen, P., Wu, X. Y., Chen, J. H., Xu, L. J., Chen, G. N., & Fu, F. F. (2011). A signal-on electrochemiluminescence aptamer biosensor for the detection of ultratrace thrombin based on junction-probe. Biosensors and Bioelectronics, 26(5), 2645–2650. https://doi.org/10.1016/j.bios.2010.11.028