School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
Key Laboratory of Urban Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai 200240, China.
Biosensors (Basel). 2020 Nov 30;10(12):195. doi: 10.3390/bios10120195.
The current work demonstrates an electrochemical aptasensor for sensitive determination of Cd based on the Ti-modified CoO nanoparticles. In this unlabeled system, Ti-modified CoO nanoparticles act as current signal amplifiers modified on the screen-printed carbon electrode (SPCE) surface, while the derivative aptamer of Cd works as a target recognizer. In addition, the sensing is based on the increase in electrochemical probe thionine current signal due to the binding of aptamer to Cd via specific recognition. In the current study, key parameters, including aptamer concentration, pH, and incubation time were optimized, respectively, to ensure sensing performance. Cyclic voltammetry was used not only to characterize each preparation and optimization step, but also to profile the bindings of aptamer to Cd. Under optimal conditions, Cd can be determined in a linear range of 0.20 to 15 ng/mL, with a detection limit of 0.49 ng/mL, significantly below the maximum concentration limit set by the U.S. Environmental Protection Agency. Based on comparative analysis and the results of recovery test with real samples, this simple, label-free but highly selective method has considerable potential and thus can be used as an in-situ environmental monitoring platform for Cd testing.
当前的工作展示了一种基于 Ti 修饰的 CoO 纳米粒子的电化学适体传感器，用于灵敏地测定 Cd。在这个无标记系统中，Ti 修饰的 CoO 纳米粒子作为电流信号放大器修饰在丝网印刷碳电极（SPCE）表面，而 Cd 的衍生适体则作为目标识别器。此外，传感是基于电化学探针硫堇电流信号的增加，这是由于适体通过特异性识别与 Cd 的结合。在本研究中，分别优化了适体浓度、pH 值和孵育时间等关键参数，以确保传感性能。循环伏安法不仅用于表征每个制备和优化步骤，还用于描绘适体与 Cd 的结合。在最佳条件下，Cd 可以在 0.20 至 15 ng/mL 的线性范围内被测定，检测限为 0.49 ng/mL，明显低于美国环境保护署设定的最大浓度限值。基于比较分析和真实样品回收试验的结果，这种简单、无标记但高度选择性的方法具有相当大的潜力，因此可作为 Cd 测试的原位环境监测平台。
