Versatile Electrochemiluminescent Biosensor for Protein鈥揘ucleic Acid Interaction Based on the Unique Quenching Effect of Deoxyguanosine-5鈥?phosphate on Electrochemiluminescence of CdTe/ZnS Quantum Dot

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• 作者：Peng Zhao ; Lifen Zhou ; Zhou Nie ; Xiahong Xu ; Wang Li ; Yan Huang ; Kaiyu He ; Shouzhuo Yao
• 刊名：Analytical Chemistry
• 出版年：2013
• 出版时间：July 2, 2013
• 年：2013
• 卷：85
• 期：13
• 页码：6279-6286
• 全文大小：378K
• 年卷期：v.85,no.13(July 2, 2013)
• ISSN：1520-6882

文摘

In this paper, the efficient quenching effect of deoxyguanosine-5鈥?phosphate (dGMP) on anodic electrochemiluminescence (ECL) of the CdTe/ZnS quantum dots (QDs) is reported for the first time. This ECL quenching was found to be specific for free dGMP and not observed for dGMP residues in different DNA structures. The unique dGMP-based QDs ECL quenching was then utilized to develop a versatile biosensing strategy to determine various protein鈥揇NA interactions with the assistance of exonuclease, Exo I, to hydrolyze DNA and liberate dGMP. Taking single-stranded DNA binding protein (SSB) and thrombin as examples, two novel detection modes have been developed based on dGMP鈥換Ds ECL strategy. The first method used hairpin probes and SSB-promoted probe cleavage by Exo I for facile signal-off detection of SSB, with a wide linear range of 1鈥?00 nM and a low detection limit of 0.1 nM. The second method exploited aptamer鈥搕hrombin binding to protect probes against Exo I degradation for sensitive signal-on detection of thrombin, giving a linear response over a range of 1鈥?50 nM and a detection limit as low as 0.1 nM. Both methods were homogeneous and label-free without QDs or DNA modification. Therefore, this dGMP-specific QDs ECL quenching presents a promising detection mechanism suitable for probing various protein鈥搉ucleic acid interactions.