In this paper, a sensitive and selective sensor for detecting colon cancer cells based on nanoparticle covalent modified anti-human epithelial cell adhesion molecule (EpCAM) antibody is developed. The transmission electron microscope (TEM) images showed that the nanoparticle and functionalized nanoparticle had good decentrality for application. The NaIO(4) oxidation method, which was used as oxidizing antibody for immobilization of conjugating antibody on the silica-coated fluorescent nanoparticles, maintained the activities of antibodies very well. The fluorescence microscopy imaging and flow cytometer (FCM) experiments demonstrated that the nanosensor could increase the signal intensity obviously and distinguish three kinds of target cells (colo205, sw480 and NCM460) well. The membrane and nuclear staining showed the distribution and abundance of EpCAM in cells' membrane. It also provides a possibility to quantify special membrane proteins on different regions of cells' surface. At the end, the result of detecting a simple sample proved that colo205 cells were selected by anti-EpCAM antibody nanosensors in this environment, and made a good foundation for subsequent research.
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