Thioflavin T as an Efficient G-Quadruplex Inducer for the Highly Sensitive Detection of Thrombin Using a New F枚ster Resonance Energy Transfer System

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• 作者：Xingfen Liu ; Xiaoxiao Hua ; Quli Fan ; Jie Chao ; Shao Su ; Yan-Qin Huang ; Lianhui Wang ; Wei Huang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：August 5, 2015
• 年：2015
• 卷：7
• 期：30
• 页码：16458-16465
• 全文大小：371K
• ISSN：1944-8252

文摘

We report a new F枚ster resonance energy transfer (FRET) system that uses a special dye, thioflavin T (ThT), as an energy acceptor and a water-soluble conjugated polymer (CP) with high fluorescence as an energy donor. A simple, label-free, and sensitive strategy for the detection of thrombin in buffer and in diluted serum was designed based on this new system using ThT as an efficient inducer of the G-quadruplex. The difference between the blank and the positive samples was amplified due to distinctive FRET signals because thrombin has little effect on the intercalation of ThT into the G-quadruplex. In the absence of the target, ThT induces the aptamer to form a G-quadruplex and intercalates into it with strong fluorescence. The electrostatic attractions between the negatively charged G-quadruplex and positively charged CP allow a short donor鈥揳cceptor distance, resulting in a high FRET signal. However, in the presence of the target, the aptamer forms a G-quadruplex鈥搕hrombin complex first, followed by the intercalation of ThT into the G-quadruplex. A long distance exists between the donor and acceptor due to the strong steric hindrance from the large-sized thrombin, which leads to a low FRET signal. Compared with previously reported strategies based on the FRET between the CP and dye, our strategy is label-free, and the sensitivity was improved by an order of magnitude. Our strategy also shows the advantages of being simple, rapid (about 50 min), sensitive, label-free, and low-cost in comparison to strategies based on the FRET between quantum dots and dyes.