title: A signal-on electrochemiluminescence aptamer biosensor for the detection of ultratrace thrombin based on junction-probe.
abstract: 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)(3)(2+)-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)(3)(2+)-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)(3)(2+). 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)(3)(2+), 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(-15) M has been developed. The success in the present biosensor served as a significant step towards the development of monitoring ultratrace thrombin in clinical detection.
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Pingping
authors.initials: P
authors.lastname: Chen
authors.forename: XiaoYan
authors.initials: X
authors.lastname: Wu
authors.forename: JingHua
authors.initials: J
authors.lastname: Chen
authors.forename: LiangJun
authors.initials: L
authors.lastname: Xu
authors.forename: GuoNan
authors.initials: G
authors.lastname: Chen
authors.forename: FengFu
authors.initials: F
authors.lastname: Fu
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008163:Luminescent Measurements / Q000295:instrumentation*; D008832:Microchemistry / Q000295:instrumentation*; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D013917:Thrombin