The Synthesized Of Complex Non-viral Vecor And The Study Of Its Biological Properties

Cationic liposomes is sensitive for anionic polyelectrolyte anion.It can transfer charged DNA into cells high negatively but also transfer RNA, ribosomal, large charged molecules and other macromolecules. The transfection efficiency is many times higher than other lioosomes. However, The transfection efficiency of cationic liposomes, compared with the viral vector, is less efficient, and it has cell cytotoxicity. Cationic lipids synthesized by our group were prepared into liposomes with different additives. The ability of complexing of liposomes and pDNA were analyzed. The transfection efficiency and cell cytotoxicity in vitro are studied.Cationic liposomes were prepared by thin-film ultrasonic technique. The condensation of plasmid DNA (pGFP-N2) was studied through agarose gel electrophoresis and the morphology was analyzed by atomic force microscope (AFM). The transfection efficiency of lipoplex of Hep-2 cells was obtained based on green fluorescent protein (GFP) expression by inverted fluorescent microscopy using lipofectamine2000 and DOTAP as contrast. Transfection conditions were optimized and the cell toxicity was evaluated using MTT assay.The complexing ability was enhanced by adding little or equimolar DOPE, but descend. The complexing ability is no change by adding sucrose ester and increased obsviously after adding chitosan. chitosan. Transfection efficiency was decreased after adding sucrose ester, increased after adding DOPE and can increased obsviously after adding chitosan. After vacuum drying we could observe the appearance of the sample particles by atomic force microscopy. Cationic liposomes formed in the mica particles were spherical or oval shape, and their distribution was more uniform; cationic liposome /DNA complexes on mica particles were irregular shape, their distribution was uneven and larger compared with blank liposomes. Chitosan-modified liposome / DNA complexes particle size become larger, and the shape is more irregular. Adding sucrose ester and DOPE, the transfection efficiency become higher; the transfection efficiency of chitosan-modified liposome has improved significantly. But the MTT Cytotoxicity has shown that adding DOPE and chitosan into liposomes reduced Cytotoxicity, while adding sucrose esters liposomes increased Cytotoxicity.