脱氧核酶
检出限
生物传感器
核酸外切酶 III
纳米棒
电化学
滚动圆复制
石墨烯
组合化学
劈开
水溶液中的金属离子
胸腺嘧啶
化学
DNA
适体
材料科学
纳米技术
电极
离子
色谱法
生物化学
DNA复制
物理化学
有机化学
基因
生物
大肠杆菌
遗传学
作者
Hui Liu,Jinshui Wang,Huali Jin,Min Wei,Wenjie Ren,Yurong Zhang,WU Ligen,Baoshan He
标识
DOI:10.1016/j.snb.2020.129215
摘要
A sensitive electrochemical biosensor was constructed for Hg2+ detection based on peonylike Cu-MOFs in situ growth of PtPd NPs bimetallic label S1 and Mg2+-dependent DNAzyme-driven DNA Walker dual amplification signal strategy. The hairpin DNA (HP) and signal label [email protected] NPs/S1 were first used to self-assemble on the gold nanorods/poly (diallyldimethylammonium chloride) functionalized graphene (AuNRs/PDDA-Gr) modified electrode, at this time, Cu ions can undergo a valence change to produce a larger initial signal. Here, we designed S2 that can perform dual functions and contains two sequences, on was a substrate sequence of the Mg2+-dependent DNAzyme and the other was a sequence complementary to HP. In the presence of target Hg2+, HP was opened and hybridized with enzymatically sequenced DNA Walker (S2) to preferentially form thymine-Hg2+-thymine (T-Hg2+-T). Then, DNA Walker exhibited catalytic activity of DNAzyme in the presence of Mg2+ to continuously cleave [email protected] NPs/S1, resulting in a decrease of electrochemical signal. Under optimal conditions, the change of current was linearly related to the negative logarithm of the Hg2+ concentration in the detection range of 0.001–100 nM with a low detection limit of 0.52 pM. Moreover, the proposed aptasensor was successfully applied in detection of milk powder samples.
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