White Ryan J, Plaxco Kevin W
Department of Chemistry and Biochemistry University of California, Santa Barbara, Santa Barbara, CA 93106-9510.
Proc SPIE Int Soc Opt Eng. 2009;7321:732105. doi: 10.1117/12.820419.
Electrochemical aptamer-based sensors (E-AB sensors) represent a promising new approach to the detection of small molecules. E-AB sensors comprise an aptamer that is attached at one end to an electrode surface. The distal end of the aptamer probed is modified with an electroactive redox marker for signal transduction. Herein we report on the optimization of a cocaine-detecting E-AB sensor via optimization of the geometry of the aptamer. We explore two new aptamer architectures, one in which we concatenate three cocaine aptamers into a poly-aptamer and a second in which we divide the cocaine aptamer into pieces connected via an unstructured, 60-thymine linker. Both of these structures are designed such that the reporting redox tag will be located farther from the electrode in the unfolded, target-free conformation. Consistent with this, we find that signal gains of these two constructs are two to three times higher than that of the original E-AB architecture. Likewise all three architectures are selective enough to deploy directly in complex sample matrices, such as undiluted whole blood, with all three sensors successfully detecting the presence of cocaine. The findings in this ongoing study should be of value in future efforts to optimize the signaling of electrochemical aptamer-based sensors.
基于电化学适配体的传感器（E-AB传感器）是检测小分子的一种很有前景的新方法。E-AB传感器包含一个适配体，该适配体一端连接到电极表面。被探测的适配体远端用一个电活性氧化还原标记物进行修饰，用于信号转导。在此，我们报告通过优化适配体的几何结构对可卡因检测E-AB传感器进行优化。我们探索了两种新的适配体结构，一种是将三个可卡因适配体连接成一个多适配体，另一种是将可卡因适配体分成通过一个无结构的60个胸腺嘧啶连接子连接的片段。这两种结构的设计都是为了使报告氧化还原标签在未折叠的、无靶标的构象中距离电极更远。与此一致的是，我们发现这两种构建体的信号增益比原始E-AB结构高两到三倍。同样，所有三种结构都具有足够的选择性，可以直接部署在复杂的样品基质中，如未稀释的全血，所有三种传感器都成功检测到了可卡因的存在。这项正在进行的研究结果对于未来优化基于电化学适配体的传感器信号传导的努力应该具有价值。
