Abstract

This study aimed to develop an aptasensor for paraquat detection by gold nanoparticles. The specific aptamer for paraquat was selected by using the SELEX process via capillary electrophoresis. Sixty-three aptamer candidates were amplified by asymmetric PCR and screened for paraquat binding using gold nanoparticles (AuNPs). Aggregation of AuNPs was specifically induced by desorption of paraquat binding aptamers from the surface of AuNPs as a result of aptamer–target interaction leading to the color change from red to purple. Aptamer 77F with the following sequence: 5′-AGGCTTACACCTGAAAAGCGGCTTAATTTACACTACTGTAT-3′ was selected as a highly specific aptamer for paraquat. The detection limit of paraquat was 0.267 µg/mL by colorimetry and 1.573 µg/mL by the quartz crystal microbalance (QCM) technique. This aptamer showed specificity for paraquat by colorimetry. Dimethyl phophite, diethyl phophite and O,O diethyl thiophosphate potassium salt did not react by colorimetry but, exhibited a weak nonspecific reaction by QCM. This is first time that an aptasensor was used for detection of paraquat based on QCM. However, the aptasensor based on the colorimetric method simply uses a generation of a signal that can be detected by the naked eye. This technique is rapid, low cost easy to use and suitable for on-site detection of herbicide residue.

摘要

这项研究旨在开发一种适用于金纳米颗粒百草枯检测的适体传感器。百草枯的特异性适体是通过毛细管电泳通过SELEX工艺选择的。通过不对称PCR扩增了63个适体候选物，并使用金纳米颗粒（AuNPs）筛选了百草枯的结合物。百草枯结合适体从AuNPs的表面解吸，特别是诱导了AuNP的聚集，这是由于适体与靶标相互作用导致颜色从红色变为紫色。选择具有以下序列的适体77F：5'-AGGCTTACACCTGAAAAGCGGCTTAATTTACACTACTGTAT-3'作为百草枯的高度特异性适体。用比色法测定百草枯的检出限为0.267 µg / mL，用石英晶体微量天平（QCM）技术测定的为1.573 µg / mL。该适体通过比色法显示出对百草枯的特异性。亚磷酸二甲酯，亚磷酸二乙酯和O，O二乙基硫代磷酸钾盐未通过比色法反应，但通过QCM表现出较弱的非特异性反应。这是第一次将适体传感器用于基于QCM的百草枯检测。然而，基于比色法的适体传感器仅使用可以由肉眼检测的信号的产生。该技术快速，低成本，易于使用，适用于现场检测除草剂残留。基于比色法的适体传感器仅使用可以通过肉眼检测到的信号来生成信号。该技术快速，低成本，易于使用，适用于现场检测除草剂残留。基于比色法的适体传感器仅使用可以通过肉眼检测到的信号来生成信号。该技术快速，低成本，易于使用，适用于现场检测除草剂残留。