基于壳聚糖包埋二氧化硅-亚甲基蓝纳米复合物的电流型癌胚抗原免疫传感器的研究

Amperometric immunosensor for carcinoembryonic antigen based on chitosan entrapped SiO2 and methylene blue nanocomposite

合成了一种新型的SiO2-亚甲基蓝(SiO2-MB)纳米复合物。SiO2-MB纳米复合物具有不同于一般的纳米SiO2的性质,它能将MB的电子转移到电极表面,而且更重要的是减小了MB的渗漏。SiO2-MB纳米复合物作为免疫传感器的媒介体使用,并采用壳聚糖(CS)包埋此复合物形成CS-SiO2-MB复合膜滴涂于洁净的玻碳电极(GCE)表面,然后在复合膜的表面固定纳米金(nano-Au)并吸附癌胚抗体(anti-CEA),制备出了性能良好的电流型免疫传感器。通过循环伏安考察了电极的电化学特性,并采用透射电子显微镜(TEM)对SiO2-MB纳米复合物的微观结构进行了表征。在最优条件下,该传感器在癌胚抗原(CEA)浓度为1～80ng/mL范围内有良好的线性关系,检测下限为0.3ng/mL(3倍信噪比)。而且,该传感器制作简单,检测快速,稳定性较好。

A novel inorganic - organic nanocomposite was synthesized by SiO2 and methylene blue （MB） in our experiment. The prepared material had some characteristics with different from common SiO2 nanoparticles spheres, which was able to transfer the electron of the MB to electrode, and it was important that it reduced leakage of the MB. The SiO2 - MB nanocomposite was acted as mediator of the immunosensor, and was entrapped by CS forming CS - SiO2 - MB composite membrane to dip on the surface of clean glass carbon electrode, then gold nanopartieles colloid （nano - Au） were adsorbed on the composite film. Carcinoembryonie antibody （Anti - CEA） was finally modified onto nano - Au/CS - SiO2 - MB film, so that constructed a good immunosensor. The fabricated procedures and electro- chemical behaviors were characterized with cyclic voltammetry （CV）, and the microstructure of SiO2 - MB nanocom-posite was also characterized with transmission electron microscope （TEM） . Under optimal conditions, the immunosensor was sensitive to CEA with a detection limit of 0. 3 ng/mL （at 3δ） and the linear range was from 1 to 80 ng/mL. Moreover, the simplification, rapidity and stability of the prepared immunosensor were acceptable.