title: Triple Quenching of a Novel Self-Enhanced Ru(II) Complex by Hemin/G-Quadruplex DNAzymes and Its Potential Application to Quantitative Protein Detection.
abstract: Herein, a novel "on-off" electrochemiluminescence (ECL) aptasensor for highly sensitive determination of thrombin has been constructed based on the triple quenching of the effect of hemin/G-quadruplex DNAzymes upon the Ru(II) complex-based ECL system. First, a strong initial ECL signal was achieved by the dual amplification strategies of (i) intramolecular coreaction of a self-enhanced Ru(II)-based molecule (PTCA-PEI-Ru(II)) and (ii) intermolecular coreaction between PTCA-PEI-Ru(II) and nicotinamide adenine dinucleotide (NADH), which was named the signal-on state. Then, a novel triple quenching of the effect of multifunctional hemin/G-quadruplex DNAzymes upon the Ru(II) complex-based ECL system was designed to realize the desirable signal-off state, which was outlined as follows: (i) the hemin/G-quadruplex DNAzymes mimicked NADH oxidase to oxidize NADH and in situ generate the H2O2, consuming the coreactant of NADH; (ii) its active center of hemin could oxidize the excited state PTCA-PEI-Ru(II)* to PTCA-PEI-Ru(III), making the energy and electron transfer quench; (iii) it also acted as horseradish peroxidase (HRP) to catalyze the H2O2 for in situ producing the quencher of O2. Based on triple quenching of the effect of hemin/G-quadruplex DNAzymes, the highly sensitive "on-off" thrombin aptasensor was developed with a wide linear detection range of 1.0 × 10(-14) M to 1.0 × 10(-10) M and a detection limit down to the femtomolar level.
authors.affiliation: †Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhao
authors.affiliation: †Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.|‡College of Biological and Chemical Engineering, Panzhihua University, Panzhihua 617000, China.
authors.forename: Ni
authors.initials: N
authors.lastname: Liao
authors.affiliation: †Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuo
authors.affiliation: †Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Ya-Qin
authors.initials: YQ
authors.lastname: Chai
authors.affiliation: †Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Ji-Peng
authors.initials: JP
authors.lastname: Wang
authors.affiliation: †Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D021881:DNA, Catalytic / Q000737:chemistry*; D054856:G-Quadruplexes; D006427:Hemin / Q000737:chemistry*; D057230:Limit of Detection; D049449:Luminescence; D012428:Ruthenium / Q000737:chemistry*; D013917:Thrombin / Q000032:analysis
chemical_list: D056831:Coordination Complexes; D021881:DNA, Catalytic; D006427:Hemin; D012428:Ruthenium; D013917:Thrombin