Novel polyethylenimine nanogels as potential gene carriers produced via photochemistry in surfactant-free aqueous solution

Cationic polymer nanogels, positively-charged submicrometer polymeric particles that swell in water, have attracted an increasing research attentions in recent years because of their potential applications as gene carriers. In this paper, we report a novel method to synthesize polyethylenimine (PEI) nanogels with sizes ranging from 80 nm to 200 nm via UV irradiation at room temperature in aqueous solution without adding any kind of surfactants. The morphology of the nanoparticles is determined to be spherical. The nanogels are of high stability, high transfection efficiency, low toxicity and low immunogenicity, as having been confirmed by in vivo tests with mice as an animal model, and by in vitro tests with human lung and liver cancer cells as well.