Research On Gene Transfection Of Mesoporous Silica Nanoparticles In Vitro

The mesoporous silica nanoparticles get more and more important in the application of biological field with the development of research in recent years. Especially using as a gene or drug carrier, new direction and the possibility are provided for development of biological gene thearapy technology with its superior properties. In this paper, it is expected to make the nanoparticles carry the small nucleic acid molecules to purpose cells safely and efficiently.In this paper, a series of characterization of mesoporous silica nanoparticles were detected by SEM, TEM, XRD, Zeta potential and BET. The characterization results show that the nanoparticle is a kind of homogeneously dispersed spherical nanoparticles with average particle diameter about 400nm, pore diameter about 2.6nm, surface area of 795.3m2/g and highly ordered mesoporous structure. After modifying with the amino group, the Zeta potential of nanoparticles had changed to positive charge but the other characterizations did not changed. The detection of materials of the morphological characteristics shows that the material is suitable for the study of cells uptake.The herring sperm DNA(100bp), 20bp DNA and 21bp FAM-siRNA were selected to be the objective nucleic acids according to the pore diameter of the mesoporous silica nanoparticles that were used in the experiment. Then different nucleic acid were absorbed by nanoparticles.While the results of the agarose gel electrophoresis showed that the nanoparticles were able to protect the nucleic acid that absorbed into the porous from enzyme digestion and the nucleic acids can get full release from material/nucleic acid compound in certain conditions.However, the most important experiment was the research of two kinds of cancer cell (HeLa and HepG2) uptake of nanoparticles that carried different DNA and labeled with FITC in free serum. The cell uptake results got from the confocal laser microscope and flow cytometric showed that the uptake of the nanoparticles that carried different DNA was different in the same cells, of which the nanoparticles without any modification were almost no uptake. But it is interested that the cell uptake of the nanoparticles that carried higher amount of small fragments DNA was the highest, and about 90% HeLa cells internalized the MSN. While the uptake of the nanoparticles that carried low amount of DNA was more below than that of the amino modified particles without any DNA. There was not too much difference of the different cells uptake. The HeLa cell uptake of the amino modified nanoparticles that carried the siRNA with spontaneous fluorescent (FAM-siRNA) by confocal laser detection, the figure showed that the cell uptake was even higher than the uptake of the nanoparticles that absorbed higher amount of 20bp DNA.In addition, the HeLa cell uptake of mesoporous silica nanoparticles in the medium of different serum concentrations was discussed. The confocal laser microscope results showed that the concentration of serum did not affect the cell uptake. And the cells were able to have a high uptake quantity under the condition of no serum medium or completely medium.At last, the cell toxicity of nanoparticles was analyzed through MTT method. The results showed that the nanoparticles have a good biocompatibility. And both the nanoparticles modified with amino group or without any modification and the nanoparticles carried different nucleic acid all did not have an impact on the growth and the proliferation of different cancer cells.The research of the uptake of mesoporous silica nanoparticles and the cell toxicity detection provide a good theoretical basis for the application in the biological carrier and the nanoparticles carried siRNA to the targeted cells and play gene silencing effect to get gene diagnosis and treatment.