Abstract We describe a real-time, label-free aptasensor that utilizes the orientational properties of nematic liquid crystals (LCs) for detection of thrombin. The imaging principle is based on the homeotropic orientation of LC films, which can be influenced by thrombin-specific aptamers and N,N-dimethyl-N-(3-(trimethoxysilyl)propyl)-1-octadecanaminiuchloride (DMOAP) immobilized on glass slides. The interactions between thrombin and its specific aptamer, including ionic and hydrogen bonds, can interfere with the homeotropic alignment of LCs, leading to changes from ‘dark’ to ‘bright’ responses that can be visualized simply using crossed polarizers. We describe the condition for maintaining the homeotropic state of LCs, which are suitable for thrombin-specific aptamer experiments, and reactions between aptamer and several enzymes, including thrombin. This novel simple LC-based aptasensor has not only high specificity, but also high sensitivity (low detection limit of 1 pg/mL (26.7 fM)). We also note the blood coagulation reaction between fibrinogen and thrombin, which confirms that the aptamer-bound thrombin is auto-enzymatic. Our result shows that the sensitivity of the proposed sensor increases (1 pg/mL to 0.1 pg/mL) using fibrinogen.

中文翻译：

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使用基于液晶的适体传感器对凝血酶进行无标记光学检测

摘要 我们描述了一种实时的、无标记的适体传感器，它利用向列液晶 (LC) 的取向特性来检测凝血酶。成像原理基于 LC 膜的垂直取向，这可能受凝血酶特异性适体和固定在载玻片上的 N,N-二甲基-N-(3-(三甲氧基甲硅烷基)丙基)-1-十八烷基胺 (DMOAP) 的影响. 凝血酶与其特定适体（包括离子键和氢键）之间的相互作用会干扰 LC 的垂直排列，导致从“暗”响应到“亮”响应的变化，只需使用交叉偏振器即可看到。我们描述了维持 LC 垂直状态的条件，这适用于凝血酶特异性适体实验，以及适体与包括凝血酶在内的几种酶之间的反应。这种新型简单的基于 LC 的适体传感器不仅具有高特异性，而且具有高灵敏度（低检测限为 1 pg/mL (26.7 fM)）。我们还注意到纤维蛋白原和凝血酶之间的凝血反应，这证实了适体结合的凝血酶是自酶促的。我们的结果表明，使用纤维蛋白原，所提出的传感器的灵敏度增加（1 pg/mL 至 0.1 pg/mL）。