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利用CdS QDs/SiO_2纳米粒子作为电子媒介体制备了一种高灵敏度的赭曲霉毒素A(OTA)电化学适配体传感器.实验过程中,首先合成了CdS QDs/SiO_2纳米粒子,之后采用透射电子显微镜、紫外吸收光谱方法等对制备的纳米材料进行了表征.该复合材料在保持了SiO_2纳米粒子良好的生物相容性和均一性的同时增加了CdS QDs的负载量,从而有利于传感器的信号放大.在组装过程中,先将捕获探针(cDNA)固定在金电极表面,适配体与捕获探针杂交形成双链,此时没有电化学信号;当OTA存在时,适配体会与OTA结合而从电极表面脱离,再将标记有CdS QDs/SiO_2纳米复合材料的信号探针(sDNA)与电极上自由的cDNA杂交,产生电化学信号.最优条件下,传感器电化学信号强度增加值与OTA浓度在0.5 pg/m L~10.0 ng/m L范围内呈现良好的线性关系,检测限低至0.091 pg/m L.
A highly sensitive OTA electrochemical aptamer sensor was prepared using CdS QDs / SiO 2 nanoparticles as the electron mediator.In the experiment, CdS QDs / SiO 2 nanoparticles were synthesized firstly, The prepared nanomaterials were characterized by scanning electron microscopy (SEM), UV absorption spectroscopy, etc. The composites increased the loading of CdS QDs while maintaining the good biocompatibility and homogeneity of SiO 2 nanoparticles, which was in favor of the sensor signal In the assembly process, the capture probe (cDNA) is first immobilized on the surface of the gold electrode, and the aptamer is hybridized with the capture probe to form a double-stranded chain without electrochemical signal. When OTA is present, the adapter will react with OTA And then detach from the electrode surface and then hybridize the signal probe (sDNA) labeled with CdS QDs / SiO 2 nanocomposites with the free cDNA on the electrode to generate electrochemical signal.Under the optimal conditions, the increase of sensor electrochemical signal intensity It showed a good linear relationship with OTA concentration in the range of 0.5 pg / mL to 10.0 ng / mL with the detection limit as low as 0.091 pg / mL.