Study On The Interaction Of Silica-coated Fluorescent Nanoparticles With Cells And Its Application In Labeling Lysosome

Recently developed biocompatible silica-coated nanoparticles with the advantages of easy preparation and good dispersity have provided an efficient method and a novel technology for the illumination of the mechanism of life activity, study of the pathogenesis, and the diagnose and treatment in clinic medicine. Our laboratory has made great progresses and breakthrough in silica-coated nanoparticles preparation and application in biomedicine. We have also lucubrated and probed into the formation mechanism and biocompatibility of silica-coated nanoparticles. But there is still no research of the interaction between silica-coated nanoparticles and cells, and the biological mechanism of cellular uptake of silica-coated nanoparticles reported in the literature. In this paper, we investigated the interaction between silica-coated fluorescent nanoparticles and cells, and for the first time, applied silica-coated fluorescent nanoparticles to label organelle lysosome. Part â… . Research on cellular uptake of silica-coated fluorescent nanoparticles with different surface charge Uptake of amino-modified SiO₂ nanoparticles with positive surface charge and SiO₂ nanoparticles with negative surface charge by HepG cells, MCF-7 cells and L-02 cells was investigated by using the rhodamine B isothiocyanate doped in silica-coated fluorescent nanoparticles as a synchronous fluorescent signal indicator. Cellular uptake of silica-coated nanoparticles depended on nanoparticle concentration and incubation time. 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 silica-coated nanoparticles in cell biological field by pertinent modification of its surface to improve its stability in cell culture medium. Part â…¡. Primary discussion of the biolobgical mechianism of cellular uptake SiO₂ fluorescent nanoparticles The biological mechanism of uptake of SiO₂ fluorescent nanoparticles by HeLa cells was primarily discussed based on above work. Uptake of SiO₂ fluorescent nanoparticles by HeLa cells was a concentraion-, time-, and energy-dependent endocytic process. And the nanoparticle uptake increased with increasing nanoparticle concentration in the culture medium and gradually reached to saturation. Cellular uptake was inhibited by hyperosmolarity sucrose solution, K+ depletion and microtubule inhibitor nocodazole in culture medium. Thus, silica-coated nanoparticles could be transported into HeLa cells partly through adsorptive endocytosis and partly through fluid-phase endocytosis. Additionally, microtubule could be playing a certain role in controlling the transportation of silica-coated nanoparticles in cells. Part â…¢. A novel lysosome marker based on SiO2 fluorescent nanoparticles Based on the second part work, we further investigated the transportation and location of SiO2 fluorescent nanoparticles in HeLa cells. SiO2 fluorescent nanoparticles mainly located in organelle lysosome after entering the HeLa cells through endocytosis. Moreover, the high negative surface charge on the nanoparticles hindered the nanoparticles escaping from the lysosome. Based on this we constructed a novel lysosome marker. Compared with traditional lysosome marker, SiO2 fluorescent nanoparticles prepared in this paper had some advantages in photostability and circulation time in cells. So SiO2 fluorescent nanoparticles could be potentially used as a novel lysosome marker.