Construction And Evaluation Of Modified Chitosan Super-fine Particles As DNA Delivery System

The traditional double emulsion (water-in-oil-in-water) method to prepare hydrophilic DNA-loaded nanoparticles (NPs) was modified and improved to get smaller NPs and high encapsulation efficiency of DNA; Poly (D, L-lactide-co-glycolic acid) (PLGA) and chitosan-lysine(CS-LYS) or o-carboxymethyl chitosan (O-CMC) were chosen to microencapsulate pEGFP and pGL3 by improved W/O/W method due to their attractive degradation and physicochemical properties; Plasmid-loaded NPs were created to realize the transfection to the tumour cell.Two kinds of modified chitosan,CS-LYS and O-CMC was synthesized.In order to character the structure of them,FTIR and NMRwas used.The optimal synthesis condition was discussed.The results of characterizing all kinds of nanoparticles showed that: Mean size of CS-LYS/PLGA without DNA is 107.96nm Zeta potenial is 50.23eV while DNA-loaded NPs is 201.2nm, Zeta potenial is 1.71eV. O-CMC/PLGA NPs without DNA is 98.97nm Zeta potenial is 35.35eV while DNA-loaded NPs is 197.2nm, Zeta potenial is -2.00eV, hydrophilicity of both NPs are very good.The Researche of DNA release behavior from NPs showed that release kinetics of DNA from NPs was coincidence with Huguchi release,which was accordance with Zero-level release.Cell viability in vitro demonstrated that biocompatibility of PLGA/CA-LYS and PLGA/O-CMC NPs was good. The transfection of pEGFP was operated successfully by both NPs. Lipofectamine was used as a contrast.The result demostrate that the NPs is inefficient compare to the Lipofectamine. The quantitative transfection efficiency was measured by the expression of the luciferase reporter.By the transfection of pGL-3,the optimal proportion of the DNA and NPs was also measured.The transfection rate of NPs was dramatic higher than naked DNA.