State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, People's Republic of China.
Anal Chem. 2013 Jul 2;85(13):6279-86. doi: 10.1021/ac4004437. Epub 2013 Jun 19.
In this paper, the efficient quenching effect of deoxyguanosine-5'-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-DNA 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-QDs 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 1-200 nM and a low detection limit of 0.1 nM. The second method exploited aptamer-thrombin binding to protect probes against Exo I degradation for sensitive signal-on detection of thrombin, giving a linear response over a range of 1-150 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-nucleic acid interactions.
本文首次报道脱氧鸟苷 5'-磷酸(dGMP)对碲化镉/硫化锌量子点(CdTe/ZnS QDs)阳极电化学发光(ECL)的高效猝灭效应。这种 ECL 猝灭是针对游离 dGMP 的，而在不同 DNA 结构中 dGMP 残基则观察不到。然后，利用独特的基于 dGMP 的 QDs ECL 猝灭，开发了一种通用的生物传感策略，通过外切酶 Exo I 水解 DNA 并释放 dGMP，来确定各种蛋白-DNA 相互作用。以单链 DNA 结合蛋白(SSB)和凝血酶为例，基于 dGMP-QDs ECL 策略，开发了两种新的检测模式。第一种方法使用发夹探针和 Exo I 促进的探针切割，通过 ECL 信号关闭，实现对 SSB 的简便检测，线性范围为 1-200 nM，检测限低至 0.1 nM。第二种方法利用适配体-凝血酶结合来保护探针免受 Exo I 降解，用于灵敏检测凝血酶，通过 ECL 信号开启，在 1-150 nM 的范围内呈现线性响应，检测限低至 0.1 nM。这两种方法均为均相且无需标记，无需 QDs 或 DNA 修饰。因此，这种基于 dGMP 的 QDs ECL 猝灭提供了一种有前途的检测机制，适用于探测各种蛋白-核酸相互作用。
