Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
Biosens Bioelectron. 2011 Jul 15;26(11):4331-6. doi: 10.1016/j.bios.2011.04.032. Epub 2011 Apr 27.
In this work, a new signal amplification strategy based on hollow PtCo nanochains (HPtCoNCs) functionalized by bi-enzyme-horseradish peroxidase mimicking DNAzyme (HRP-DNAzyme) and glucose oxidase (GOD), as well as ferrocene-labeled secondary thrombin aptamer (Fc-TBA 2), is developed to construct a highly sensitive electrochemical aptasensor. The HRP-DNAzyme contains a special G-quadruplex structure with an intercalated hemin. With the surface area enlarged by HPtCoNCs, the amount of immobilized Fc-TBA 2, hemin and GOD can be enhanced. Under the enzyme catalysis of GOD, d-glucose is rapidly oxidized into gluconic acid accompanying with the generation of H₂O₂, which is further electrocatalyzed by Pt nanoparticles and HPR-DNAzyme to improve the electrochemical signal of Fc. With several amplification factors mentioned above, a wide linear ranged from 0.001 to 30 nM is acquired with a relatively low detection limit of 0.39 pM for thrombin. The present work demonstrates that using HPtCoNCs as labels is a promising way to amplify the analysis signal and improve the sensitivity of aptasensors.
在这项工作中，开发了一种基于双酶-辣根过氧化物酶模拟 DNA 酶（HRP-DNAzyme）和葡萄糖氧化酶（GOD）功能化的空心 PtCo 纳米链（HPtCoNCs）以及铁标记的凝血酶适体（Fc-TBA2）的新信号放大策略，用于构建高灵敏电化学适体传感器。HRP-DNAzyme 包含具有嵌入血红素的特殊 G-四链体结构。通过 HPtCoNCs 增大表面积，可以增强固定的 Fc-TBA2、血红素和 GOD 的量。在 GOD 的酶催化作用下，d-葡萄糖迅速氧化成葡萄糖酸，同时伴随着 H₂O₂的生成，H₂O₂进一步被 Pt 纳米粒子和 HRP-DNAzyme 电催化，从而提高 Fc 的电化学信号。通过上述几种放大因素，获得了从 0.001 到 30 nM 的宽线性范围，凝血酶的检测限相对较低，为 0.39 pM。本工作表明，使用 HPtCoNCs 作为标记物是放大分析信号和提高适体传感器灵敏度的一种很有前途的方法。
