Catanante Gaëlle, Mishra Rupesh K, Hayat Akhtar, Marty Jean-Louis
Laboratoire B.A.E., Université De Perpignan Via Domitia, 52 Avenue Paul Alduy, Perpignan Cedex 66860, France.
Laboratoire B.A.E., Université De Perpignan Via Domitia, 52 Avenue Paul Alduy, Perpignan Cedex 66860, France; Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS Institute of Information Technology (CIIT), Lahore 54000, Pakistan.
Talanta. 2016 Jun 1;153:138-44. doi: 10.1016/j.talanta.2016.03.004. Epub 2016 Mar 4.
This work demonstrates the development of a folding based electrochemical aptasensor using methylene blue (MB) tagged anti-Ochratoxin A (OTA) aptamers. Different aptamer coupling strategies were tested using Hexamethylenediamine, polyethylene glycol, simple adsorption and diazonium coupling mechanism. The best sensitivity was recorded by oxidation of amines using hexamethylenediamine (HDMA) on screen printed carbon electrode (SPCE). To achieve the direct detection of OTA, aptamer conjugated redox probe was used and detection was demonstrated based on the conformational changes in aptamer structure upon OTA sensing. Signaling in this class of sensors arises from changes in electron transfer efficiency upon target-induced changes in the conformation/flexibility of the aptamer probe. These changes can be readily recorded electrochemically. The developed aptasensor is unique in its own mechanism as redox probe tagged aptamer coupling such as MB has never been tried to immobilize using long carbon chain spacers as, addition of spacers would provide more sensitive detection methods. A good dynamic range 0.01-5ng/ml was obtained for OTA with Limit of detection (LOD) 0.01ng/ml and Limit of quantification (LOQ) of 0.03ng/ml respectively. The good reproducibility was recorded with RSD% of 3.75. The obtained straight line equation was y=0.4035x+0.90311, r=0.9976. We believe that the sensor design guidelines outlined here represents a general strategy for developing new folding-based electrochemical aptasensors. The developed aptasensor was extended to screen cocoa samples for OTA contamination. The cocoa samples were extracted and purified using molecular imprinted polymer (MIP) columns. The aptasensor displayed good recovery values in the range 84-85% thus, exhibited the effectiveness of proposed aptasensor for such complex matrices.
这项工作展示了一种基于折叠的电化学适体传感器的开发，该传感器使用亚甲基蓝（MB）标记的抗赭曲霉毒素A（OTA）适体。使用六亚甲基二胺、聚乙二醇、简单吸附和重氮耦合机制测试了不同的适体偶联策略。通过在丝网印刷碳电极（SPCE）上使用六亚甲基二胺（HDMA）氧化胺记录到了最佳灵敏度。为了实现对OTA的直接检测，使用了适体共轭氧化还原探针，并基于OTA传感时适体结构的构象变化进行了检测演示。这类传感器中的信号来自于目标诱导适体探针构象/柔韧性变化时电子转移效率的变化。这些变化可以很容易地通过电化学记录下来。所开发的适体传感器在其自身机制上是独特的，因为从未尝试使用长碳链间隔物固定诸如MB这样的氧化还原探针标记的适体偶联物，因为添加间隔物会提供更灵敏的检测方法。对于OTA，获得了0.01 - 5ng/ml的良好动态范围，检测限（LOD）为0.01ng/ml，定量限（LOQ）为0.03ng/ml。记录到了良好的重现性，相对标准偏差（RSD%）为3.75。得到的直线方程为y = 0.4035x + 0.90311，r = 0.9976。我们相信这里概述的传感器设计指南代表了开发新型基于折叠的电化学适体传感器的一般策略。所开发的适体传感器被扩展用于筛查可可样品中的OTA污染。使用分子印迹聚合物（MIP）柱对可可样品进行提取和纯化。该适体传感器在84 - 85%的范围内显示出良好的回收率，因此，展示了所提出的适体传感器对这类复杂基质的有效性。
