College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, 450001, PR China.
College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, 450001, PR China.
Anal Chim Acta. 2019 Nov 12;1081:59-64. doi: 10.1016/j.aca.2019.07.005. Epub 2019 Jul 10.
Herein, a signal-on electrochemical aptasensor for highly sensitive detection of thrombin (TB) was constructed based on the DNAzyme-driven DNA walker strategy. We developed a new dual functional hairpin DNA (HP) containing a substrate sequence of the Mg-dependent DNAzyme (in the loop region) and the G-quadruplex forming segment (in the stem region). The DNA walker (TBA-DWs), containing a TB aptamer and an enzymatic sequence, was introduced onto gold electrode (GE) by aptamers-target specific recognition, and thus initiated the enzymatic sequences to hybridize with the substrate sequence. Then, the DNA walker could repeatedly bind and cleave HP in the assistance of Mg, unlocking many active G-quadruplex forming sequences. Finally, hemin can further bind the G-quadruplex to form G-quadruplex/hemin complexes and generate enhanced current output. The aptasensor for TB assay showed a linear detection range from 1 pM to 60000 pM with a lower detection limit of 0.58 pM. And more, the proposed detection strategy was enzyme-free and label-free.
本文基于 DNA zyme 驱动的 DNA walker 策略，构建了一种用于高灵敏检测凝血酶 (TB) 的信号开启型电化学适体传感器。我们开发了一种新型双功能发夹 DNA (HP)，其中包含 Mg 依赖性 DNA zyme 的底物序列（在环区）和 G-四链体形成片段（在茎区）。含有 TB 适体和酶序列的 DNA walker (TBA-DWs) 通过适体靶向特异性识别被引入金电极 (GE)，从而引发酶序列与底物序列杂交。然后，在 Mg 的辅助下，DNA walker 可以反复结合和切割 HP，释放许多活性的 G-四链体形成序列。最后，血红素可以进一步结合 G-四链体形成 G-四链体/血红素复合物，并产生增强的电流输出。用于 TB 测定的适体传感器的线性检测范围为 1 pM 至 60000 pM，检测下限为 0.58 pM。此外，所提出的检测策略是无酶和无标记的。
