Self-assembled PEI nanomicelles with a fluorinated core for improved siRNA delivery

Polyethylenimine (PEI) is widely used as delivery vector for nucleic acids. However, the clinical application is limited by relatively low transfection efficacy and high toxicity. To address this problem, here fluorinated polymer technology have been proposed to modify PEI. We synthesized fluorinated PEI and prepared nanomicelles with a fluorinated core for siRNA delivery. Nanomicelles were formed by fluorous interactions. The nanomicelles possessed good buffering capacity and siRNA binding ability. Nanomicelles could protect siRNA from the RNase A degradation and show excellent colloidal stability. More importantly, the fluorinated PEI and nanomicelles achieved efficient gene transfection capacity at relatively low w/w ratios, which ensured low cytotoxicity of the formulations. In addition, the nanomicelles exhibited high levels of cellular uptake and endosomal escape, which was consistent with high transfection activity. The results suggest that fluorination of PEI and preparation of nanomicelles are a promising strategy in the design of highly efficient siRNA delivery vectors.