Triple Quenching of a Novel Self-Enhanced Ru(II) Complex by Hemin/G-Quadruplex DNAzymes and Its Potential Application to Quantitative Protein Detection

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• 作者：Min Zhao ; Ni Liao ; Ying Zhuo ; Ya-Qin Chai ; Ji-Peng Wang ; Ruo Yuan
• 刊名：Analytical Chemistry
• 出版年：2015
• 出版时间：August 4, 2015
• 年：2015
• 卷：87
• 期：15
• 页码：7602-7609
• 全文大小：452K
• ISSN：1520-6882

文摘

Herein, a novel 鈥渙n鈥搊ff鈥?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 鈥渙n鈥搊ff鈥?thrombin aptasensor was developed with a wide linear detection range of 1.0 脳 10^鈥?4 M to 1.0 脳 10^鈥?0 M and a detection limit down to the femtomolar level.