基于主客体竞争模式的凝血酶适配体传感器的研究

基于β-环糊精(β-CD)主客体竞争模式,构建了开关型凝血酶适配体电化学传感器.将末端修饰了二茂铁(Fc)的核酸适配体通过与β-CD的主客体识别固定在金电极表面,当凝血酶存在时,适配体由原来的直立线状构型变为"G-四链体",远离电极表面,适配体探针的氧化还原电流强度减小,即"Signal-off".利用此效应对凝血酶进行了灵敏检测,结果表明,在5.0×10-13~5.0×10-9 mol/L浓度范围内,凝血酶的浓度与电化学响应信号呈良好的线性关系,检出限为2.0×10-13 mol/L(3σ).与其它蛋白分子相比,本方法对凝血酶蛋白的检测具有高特异性.本传感器构建简单,再生性好,为生物血清样本中凝血酶的实时高效检测提供了方法.

Preparation of Thrombin Aptamer Sensor Based on Host Guest Competition Model

A switch thrombin aptamer sensor was constructed based on the host-guest competition mode ofβ-cyclodextrin (β-CD ) . The aptamer that modified with ferrocene ( Fc ) at its terminal was fixed on the surface of the gold electrode via the host-guest recognization with β-CD. When thrombin was present, the configuration of aptamer transformed from vertical linear to "G-quadruplex" and far away from the electrode surface, which resulted in a decrease in the redox current of the aptamer probe and produce "Signal-off"effect. On the basis of this, a high sensitive detection of thrombin was made. The detection result indicated that the thrombin concentration had a consideration linear response to the signal of aptasensor between 5 . 0 × 10-13-5. 0 × 10-9 mol/L, and as low as 2. 0 × 10-13 mol/L thrombin had been detected. This method for thrombin detection showed a higher specificity compared to other protein molecules. Besides, the sensor was constructed easily and possessed excellent regeneration, which provided a significant platform for highly efficient real-time detection of thrombin in biological serum samples.