개질화된 덱스트란 고분자를 이용한 효과적인 유전자 전달체의 합성 및 특성 연구

Abstract

Non-viral delivery systems for gene therapy have been increasingly proposed as an alternative to viral vector with safety and stability in storage, including synthetic cationic polymer such as poly(L-lysine) (PLL), polyethylenimine (PEI), and cationic lipid. However, lack of transfection efficiency is the main hurdle to the success of gene therapy. In this study, to render this barrier, we has modified dextran, a biodegradable natural polysaccharide, with functional groups to give “cell specificity[chapter II]” and “cell penetrating capacity[chapter III]” respectively which play key roles in increasing transfection efficiency as a non-viral polymeric gene carrier. Dextran-g-spermine (Dex-Spm) was successfully synthesized by oxidation of dextran under favorable conditions, followed by chemical modification through reductive amination. In chapter II, for achieving cell specific-targeting, galactosylated cucurbituril (galCB) was bound to the cationic polysaccharides via host-guest interaction between spermine and galCB, which is named as Dex-spm40k-gCB. In chapter III, guanidinium side groups incorporated on dextran backbone, gua-dex70k-spm, have been known to enhance gene transfer efficacy due to cell membrane-penetrating properties, forming possible hydrogen bonding with phosphate anions of cell membrane as well as maintaining higher ionic interaction ability with DNA. The formation and substitution degree of modified dextrans were confirmed by NMR, IR, GPC and elemental analysis. The physicochemical properties of modified dextrans were analyzed by particle size measurement and zeta potential assay. The transfection efficiency and cytotoxicity of modified dextrans were investigated in a variety of cell lines. Furthermore, the movement of polymer carriers complexed with genes that were labeled with fluorescence was observed via FACS and CLSM.