Establishing Gene Delivery Systems Based on Small-Sized Chitosan Nanoparticles

摘要

Chitosan is a natural cationic polysaccharide,which is often used for preparing biomedical materials because of its high biocompatibility.In this study,chitosan with a molecular weight of 160kDa was chosen to prepare chitosan nanoparticles(CSNPs)as gene vectors by ionic cross-linking with tripolyphosphate(TPP).CSNPs were characterized in terms of particle size,zeta potential,and polydispersity index(PDI)using a Zetasizer,and morphology was evaluated by transmission electron microscopy(TEM).Fur-thermore,the cytotoxicity and biocompatibility of CSNPs were correspondingly examined by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay and histological examination.Agarose gel electrophoresis and UV spectrophotometric methods were performed to measure the loading capacity.The cell transfection efficiency of CSNPs loaded with plasmids or siRNA was analyzed by fluorescence microscopy or laser scanning confocal microscopy.The results showed that CSNPs were prepared successfully by the ionic gelation method,which had a smaller particle size(100nm-200nm),stable dispersibility,low cytotoxicity,good tissue-biocompatibility,and high gene-loading efficiency.These CSNPs could transfer the plasmids or siRNA to cells.How-ever,CSNPs might have a much higher transfection efficiency for siRNAs than for plasmids,which implies that CSNPs might be a safer and more efficient vector for delivering siRNAs rather than plasmids.