Preparation And Properties Of Cationic Curdlan Gene Nano-carriers With Transmembrane Function

In the process of gene therapy,construction of high safety and hightransfection delivery carrier is the prerequisite and key to the realization of gene therapy.As a kind of natural polysaccharide,beside a variety of biological functions,curdlan are attracting wide attention in biomedical field in that there are a large number of active groups on the main chain,which are easy to be chemically modified to synthesize derivatives with various functions.In this thesis,curdlan was chemically modified by"click"reaction,and abetter water-soluble aminated curdlan?Cur-PLG?was prepared,then aminated curdlan was modified with appropriate amount of lactose acid?Lac?or urocanic acid?UA?to produce curdlan derivatives?Cur-Lac and Cur-UA?.The structure of compounds were confirmed by FTIR,¹H NMR and ¹³CNMR,and their molecular weight is measured by GPC.The morphology and diameter were observed by scanning electron microscope?SEM?and dynamic light scattering?DLS?.The cytotoxicity,hydrogen loading and DNA binding ability of compounds were determined by MTT assay,gel electrophoresis and acid-base titration.The results demonstrate that the average size of Cur-Lac is between 100-200nm,that is less than100nm for Cur-UA.Those two kinds of nanoparticles can combine well with DNA under suitable nitrogen and phosphorus ratio.Cur-Lac with a variety of degrees of substitution?Cur-Lac5%,Cur-Lac10%and Cur-Lac20%?showed extremely low cytotoxicities to A549 cell and Hela cell,and Cur-UA with lower substitution?Cur-UA5%and Cur-UA10%?degree showed low cytotoxicities to A549 and Hela cell.Generally,we synthesized two kinds of gene nanocarriers based on curdlanwith transmembrane ability,which are expected to be used for gene delivery in vivo and in vitro.The results provide advanced methods and useful references for the development of new-style curdlan gene carriers.