Nanoparticles composed by oligochitosan and polyethylenimine for gene delivery

Cationic carriers including polyethylenimine, liposomes, and chitosan have been used to transfer plasmid DNA in vitro by condensing anionic DNA. Here, oligochitosan (OC) was found to have capacity for in-vitro gene delivery in four cell lines. Plasmid containing green fluorescent protein (GFP) gene was used as a reporter gene. The transfection efficacy and cell viability of the transfection vehicles were analyzed by using a high-throughput image analyzer. We found that DNA polyplexes formed by high dosage of OC could be efficiently delivered into the cells. The combination of OC and polyethylenimine (PEI) were found to significantly enhance the fluorescence protein expression. The introduction of oligochitosan in PEI-mediated transfection could increase the transfection efficacy and could reduce the toxicity of PEI. Additionally, the synergistic effects of PEI and OC were confirmed in CHO, Caco2, Hep-SK, and 3T3 cell lines. The detailed mechanism of PEI and oligochitosan on transfection was investigated by using gel retardation and DNase degradation experiments. A facile and inexpensive construction of gene delivering vehicles was developed herein by using oligochitosan and PEI.