School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
Biosens Bioelectron. 2019 Sep 1;140:111352. doi: 10.1016/j.bios.2019.111352. Epub 2019 May 28.
Atrazine (ATZ) is one of the most widely used and highly toxic triazine herbicides in the world. Photoelectrochemical (PEC) method is an attractive and sensitive alternate for ATZ. However, for conventional PEC sensors, recognition elements usually need to immobilize on electrode surface, where a complex procedure is unavoidable and the reproducibility of sensors fabrication is usually poor. Therefore, we herein proposed a new and feasible strategy for developing a signal-on immobilization-free PEC aptasensor to ATZ. Aptamer for ATZ is combined with graphene to obtain APT-GN complex, serving as the recognition element in solution. TiO nanotubes (NTs) electrode deposited with Au nanoparticles (NPs) is used as the substrate electrode. After further self-assembled with 1-Mercaptooctane (MCT), the photo-generated carriers transfer between the resultant electrode and the electrolyte will be blocked, leading to a signal-off of the photocurrent. But when sensing ATZ, aptamers on APT-GN will be grasped by ATZ, leaving free graphene to assemble onto MCT/Au NPs/TiO NTs, which will largely "turn on" the photocurrent response of the substrate electrode due to the efficient carrier transport efficiency of graphene. Meanwhile, simultaneous addition of deoxyribonuclease I (DNase I) can bring about further cycling amplification of the signal enhancement. The as-designed PEC aptasensor exhibits a linear range from 50.0 fM to 0.3 nM with detection limit of 12.0 fM for ATZ. Since the reaction of recognition elements and targets ATZ occurs in homogeneous solution rather than on the photoelectrode surface, this PEC aptasensor exhibits advantages of high stability, anti-interference ability, reproducibility, and wide pH and ion strength feasibility range. A promising immobilization-free aptasensing platform has thus been provided not only for ATZ but also for other kinds of environmental pollutants.
阿特拉津（ATZ）是世界上使用最广泛、毒性最强的三嗪类除草剂之一。光电化学（PEC）方法是一种有吸引力和敏感的替代方法。然而，对于传统的 PEC 传感器，识别元件通常需要固定在电极表面上，这是一个不可避免的复杂过程，并且传感器制造的重现性通常很差。因此，我们在此提出了一种新的可行策略，用于开发用于 ATZ 的信号开启无固定化 PEC 适体传感器。ATZ 的适体与石墨烯结合，获得 APT-GN 复合物，作为溶液中的识别元件。沉积有金纳米颗粒（NPs）的 TiO 纳米管（NTs）电极用作基底电极。进一步与 1-巯基辛烷（MCT）自组装后，所得电极与电解质之间的光生载流子转移将被阻断，导致光电流信号关闭。但是，当检测 ATZ 时，APT-GN 上的适体将被 ATZ 捕获，留下游离的石墨烯组装到 MCT/Au NPs/TiO NTs 上，由于石墨烯的高效载流子传输效率，这将大大“开启”基底电极的光电流响应。同时，同时添加脱氧核糖核酸酶 I（DNase I）可以进一步循环放大信号增强。所设计的 PEC 适体传感器对 ATZ 的线性范围为 50.0 fM 至 0.3 nM，检测限为 12.0 fM。由于识别元件和靶标 ATZ 的反应发生在均相溶液中，而不是在光电电极表面上，因此该 PEC 适体传感器具有高稳定性、抗干扰能力、重现性以及宽 pH 和离子强度可行性范围的优点。因此，不仅为 ATZ 而且为其他类型的环境污染物提供了一种有前途的无固定化适体传感平台。
