γ-Ray-Radiation-Scissioned Chitosan as a Gene Carrier and Its Improved in vitro Gene Transfection Performance

Chitosan (CS) is expected to be an ideal gene carrier for its high biosafety. In this work, CS with low molecular weight were prepared through the γ -ray radiation on the acetic acid solution of CS. The CS chains were scissioned under the γ -ray radiation, and the molecular weight (MW) of CS decreased with the absorbed dose. When the absorbed dose was above 30 kGy, the molecular weight of CS decreased about an order of magnitude. The γ -ray-radiation-scissioned CS can effectively bind with plasmid (pEGFP) through complex coacervation method, forming pEGFP/ γ -ray-radiation-scissioned CS complex particles with a size of 200–300 nm. The complex particles have good stability and little cytotoxicity. The in vitro gene transfection efficiencies of the pEGFP/ γ -ray-radiation-scissioned CS complex particles were investigated by fluorescence microscope and flow cytometry. The results showed that the gene vectors using γ -ray-radiation-scissioned CS as the carrier will possess better gene transfection efficiency than those using natural high-MW CS as the carrier. The higher the absorbed dose, the smaller the MW of CS and the better transfection efficiency of the corresponding gene vector. This work provides a green and simple method on the preparation of CS-based gene vectors with high efficiency and biosafety.