Dots With Hela, Cos-7 Cells

The usages of semiconductor nanocrystal material, quantum dots have displayed an increasing tendency over the past decade in scientific researches and industrial fields, as well as the transition from electronic materials science to biological science applications. The application of quantum dots in life science has substantially impacted many research areas, such as biological imaging, photo therapy, drug/gene delivery and solar battery. The key problem is how to implement the interactions between quantum dots and cell through adjusting and controlling properties of quantum dots. In view of the special structure of quantum dots, scientists pay more attention to the research of their potential toxicity based on the properties of quantum dots in the applications of cell biology. In this thesis, the promising applications of quantum dots in biology and medicine were studied, some interesting results were reported as the followings.1. The biolobgical mechianism of cellular taking up quantum dots was studied by fluorescent spectrometry of nanoparticles. Quantum dots enter Hela via caveolin-mediated endocytic pathway with closely related to temperature. Uptake of quantum dots were driven by the electrostatic interaction between positive surface charge of quantum dots with negative surface charge of Hela cells and Cos-7 cells. The cellular uptake of silica-coated nanoparticles is depended on nanoparticle concentration and incubation time. The quantum dots show that quantum dots penetrate plasma into Hela cells and COS-7 cells via clathrin-mediated endocytosis. The surface charge of nanoparticles and the serum in cell culture medium also affected the cellular uptake. These results offered a theoretical foundation for better application of quantum dots in cell biology by pertinent modification of its surface to improve its stability in cell culture medium.2. Based on the last part work, we further investigated the transportation and location of fluorescent nanoparticles in HeLa cells. The fluorescent quantum dots are mainly located in organelle lysosome after entering the HeLa cells through endocytosis. The endoeytosised quantum dots and the cells were exmained under confocal:The disruption of cytoplasm around nanopartieles, tumefaction, expansion of endoplasmic reticulums, swelling and collapsing of mitoehondrias, disorder of mitohcondrias crista, expansion of nuclear space, shrinkage of nuclear envelope, After incubation with quantum dots, the Hela cells appeared'ladder', which could be concluded that quantum dots induced apoptosis of Hela cells.