Gene Expression and Pulmonary Toxicity of Chitosan-graft- Polyethylenimine as Aerosol Gene Carrier.

Chitosan-graft-polyethylenimine (CHI-g-PEI) copolymer has been used for the improvement of low transfection efficiency of chitosan. The present study aims to test the pulmonary toxicity and efficiency of CHI-g-PEI as an aerosol gene carrier. Mice were exposed to aerosol containing green-fluorescent protein (GFP)-polyethylenimine (PEI) or GFP-CHI-g-PEI complexes for 30 min during the development of our nose-only exposure chamber (NOEC) system. CHI-g-PEI-mediated aerosol delivery demonstrated 15.65% enhancement of the fluorescence intensity. Compared to PEI, CHI-g-PEI showed no significant pulmonary toxicity. In summary, using CHI-g-PEI is safe and shows high transfection in aerosol gene delivery to animals, and enhanced efficiency was achieved through our aerosol gene delivery system. Therefore, CHI-g-PEI and this system would be applicable to future study for aerosol gene therapy.