Preparation Of Chitosan Derivatives And Their Application In Gene Delivery

Chitosan, a natural polysaccharide, has a lot of outstanding properties, such asbiocompatibility and biodegradablility. Recently, chitosan is considered as a potential genevector because of its electropositivity. Herein, we synthetized and characterized twochitosan derivatives, which can be applied in gene therapy.A series of N-(2-hydroxy)propyl-3-trimethyl ammonium chitosan chloride (HTCC)samples with three degrees of quaternization (12.4%,28.1%and43.7%) were synthesized.The physical and chemical properties of HTCC were investigated by FT-IR,1H NMR,conductometric titration, XRD and TG analysis. The results showed that HTCC had lowerthermal stability than chitosan. Cytotoxicity results indicated HTCC samples showedobviously lower cytotoxicity than polyethyleneimine. HTCC samples were able to formcomplexes with pGL3luciferase plasmid automaticly. In vitro gene transfection to Helacells results revealed that HTCC had obviously higher transfection efficiency than chitosanin delivering luciferase plasmid. These results suggested that HTCC was a promisingcandidate used for non-viral vectors.Galactosylated chitosan-hydroxypropyltrimethyam-monium (gal-HTCC) wassynthesized by galactosylation and quaternization of chitosan. The degree ofgalactosylation and quaternization are separately13.7%and30.8%. FT-IR,~1H NMR, andXRD analysis characterized the physical and chemical properties of gal-HTCC. It wasfound that water-soluble gal-HTCC showed a much better plasmid condensation capabilitythan galactosylated chitosan. Cytotoxicity results indicated that gal-HTCC showedobviously lower cytotoxicity than polyethyleneimine. In vitro gene transfection resultsrevealed that gal-HTCC had obviously higher transfection efficiency than chitosan andgal-chitosan in delivering plasmid to HepG2cells. All these results suggest that gal-HTCCcan function as a promising non-viral gene vector for efficient liver-targeted gene delivery.