脱氧核酶
适体
化学
血红素
劈开
G-四倍体
DNA
组合化学
检出限
基质(水族馆)
A-DNA
酶
线性范围
生物物理学
生物化学
分子生物学
色谱法
海洋学
地质学
生物
血红素
作者
Sheng Lei,Lingling Xu,Zi Li,Lina Zou,Gaiping Li,Baoxian Ye
标识
DOI:10.1016/j.aca.2019.07.005
摘要
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 Mg2+-dependent DNAzyme (in the loop region) and the G-quadruplex forming segment (in the stem region). The DNA walker (TBA2-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 Mg2+, 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.
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