Development of functional polyplex micelles for systemic gene therapy

Recent advances in chemistry-based engineering have developed smart nanodevices for realizing targeted therapy by rationally integrating versatile molecular technologies to achieve specific structures and functionalities. Gene therapy is one of the most intriguing targets, because nanodevices to deliver fragile DNA into pathological cells and exert effective transgene expression are indispensable for achieving this innovative therapeutic modality. The largest challenge lies in the development of an appropriate systemic delivery system that can withstand the harsh environment of circulating blood and efficiently accumulate in a targeted location for gene expression. This review focuses mainly on our polymer-based DNA delivery systems, which are fabricated from polyion complexation between plasmid DNA and functionalized poly(ethylene glycol)-based block catiomers, and highlights their development to systemic settings for application to cancer treatment.