Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering , Southwest University , Chongqing 400715 , People's Republic of China.
Anal Chem. 2019 Aug 6;91(15):10289-10294. doi: 10.1021/acs.analchem.9b02498. Epub 2019 Jul 8.
Herein, an efficient target-activated enzyme cascade electrocatalysis with low background signal was employed to establish electrochemical biosensor for ultrasensitive detection of thrombin via regulating electrocatalytic efficiency between target-induced hemin/G-quadruplex horseradish peroxidase-mimicking DNAzyme (HRP-mimicking DNAzyme) and glucose oxidase (GOx). Impressively, only when the target thrombin was introduced, the HRP-mimicking DNAzyme acting simultaneously as electrochemical signal probe would be formed to activate high-efficiency enzyme cascade electrocatalysis for reducing background signal significantly, which could overcome the defect of inevitable high background signal during the detection of target in the traditional cascade electrocatalysis of two existing bioenzymes. In addition, the detection sensitivity could be further improved by regulating the side length of rigid DNA tetrahedron (TDN) scaffold anchored HRP-mimicking DNAzyme and GOx at adjacent vertices for high enzyme cascade electrocatalytic efficiency. Consequently, the proposed biosensor demonstrated a low detection limit down to 0.3 fM for target thrombin, which provided a promising method for ultrasensitive monitoring of biomolecules in sensing analysis and disease diagnosis.
本文采用一种高效的靶标激活酶级联电化学生物传感器，具有低背景信号，通过调节目标诱导的血红素/G-四链体辣根过氧化物酶模拟 DNA 酶（HRP-mimicking DNAzyme）与葡萄糖氧化酶（GOx）之间的电催化效率，建立了用于超灵敏检测凝血酶的电化学生物传感器。令人印象深刻的是，只有当引入靶标凝血酶时，作为电化学信号探针的 HRP-mimicking DNAzyme 才会形成，从而激活高效的酶级联电化学生物催化反应，显著降低背景信号，这可以克服传统双生物酶级联电化学生物催化反应中检测靶标时不可避免的高背景信号的缺陷。此外，通过调节刚性 DNA 四面体（TDN）支架锚定的 HRP-mimicking DNAzyme 和 GOx 在相邻顶点的边长，可以进一步提高检测灵敏度，以实现高酶级联电化学生物催化效率。因此，所提出的生物传感器对靶标凝血酶的检测限低至 0.3 fM，为传感分析和疾病诊断中生物分子的超灵敏监测提供了一种有前途的方法。
