Interdisciplinary Research Center in Biomedical Materials (IRCBM), COMSATS University Islamabad, Lahore, Pakistan.
Bioengineering Laboratory, Higher National School of Biotechnology, Constantine, Algeria.
Anal Biochem. 2022 Feb 15;639:114540. doi: 10.1016/j.ab.2021.114540. Epub 2021 Dec 25.
We present in this work, an aptasensing strategy based on the DNA-templated electrodeposition of silver nanoparticles (AgNPs). The homogeneous electro-deposition of AgNPs on screen printed carbon electrode (SPCE) surface was achieved based on a unique aptamer scaffold. This was constructed by immobilizing a DNA aptamer on SPCE by electrochemical oxidation of its amine groups. The electrodeposition of AgNPs was investigated before and after the addition of the aptamer's specific target; the mycotoxin, ochratoxin A (OTA). Electrochemical characterization by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) showed the effect of the scaffold layer on the electrodeposition of AgNPs. The conformational change induced by aptamer after binding its targeted molecule affects AgNPs electrodeposition and the electron transfer thus allowing OTA detection by cyclic voltammetry. The voltammograms showed a good proportionality between the analyte concentration and the current response. The constructed platform allowed the quantitative aptasensing of OTA within the range of (1.56-400 ng/mL) and the detection limit of 0.6 ng/mL. In term of aptasensor applicability, the proposed strategy showed excellent performance in rice samples.
我们在这项工作中提出了一种基于适体的银纳米粒子（AgNPs）电沉积的适体传感策略。基于独特的适体支架，在丝网印刷碳电极（SPCE）表面上实现了 AgNPs 的均匀电沉积。该支架通过电化学氧化其胺基将 DNA 适体固定在 SPCE 上。在添加适体的特定靶标（真菌毒素 ochratoxin A（OTA））前后，研究了 AgNPs 的电沉积情况。通过循环伏安法（CV）和电化学阻抗谱（EIS）进行的电化学表征显示了支架层对 AgNPs 电沉积的影响。适体结合其靶向分子后诱导的构象变化影响 AgNPs 的电沉积和电子转移，从而允许通过循环伏安法检测 OTA。伏安图显示分析物浓度与电流响应之间存在良好的比例关系。该构建平台允许在（1.56-400 ng/mL）范围内对 OTA 进行定量适体感应，检测限为 0.6 ng/mL。就适体传感器的适用性而言，所提出的策略在稻米样品中表现出优异的性能。
