OBJECTIVETo prepare chitosan nanoparticles (NPs) as gene carriers and study its pharmaceutical characteristics and gene transfection efficiency in vitro.

METHODSThe plasmid expressing green fluorescent protein (pGFP) was used as the reporter gene, and the chitosan-pGFP NPs were prepared using a complex coacervation process. The binding of pDNA was evaluated by agarose gel electrophoresis analysis, and the encapsulation rate was determined with colorimetry. The size distribution and polydispersity of the NPs were measured by nanoparticle size analyzer, and their morphologies observed by atomic force microscope. The transfection studies were performed with LoVo cells in vitro.

RESULTSThe results of gel electrophoresis demonstrated full binding of chitosan with the pDNA by electrostatic interaction. The encapsulation rates for these NPs all exceeded 90%. The morphology of the chitosan NPs was mostly spherical and well distributed, with a mean diameter of about 209 nm and polydispersity of 0.32. The in vitro transfection of chitosan-pGFP NP was efficient in LoVo cells and the expression of green fluorescent proteins was observed under fluorescent microscope.

CONCLUSIONSChitosan NP prepared by complex coacervation can bind to the pDNA efficiently with high encapsulation rate and diameter distribution of 100 to 500 nm. These NPs allow efficient delivery of the reporter genes into cells in vitro for their expression. The chitosan-pDNA NPs may serve as an effective non-viral carrier for delivery of nucleotides into cells.