Cationic star polymer siRNA transfectants interconnected with a piperazine-based cationic cross-linker

Cationic star polymers of 2-(dimethylamino)ethyl methacrylate (DMAEMA) were prepared via the "arm-first" method under group transfer polymerization (GTP) conditions, and were interconnected using a novel, hydrophilic, positively ionizable dimethacrylate cross-linker which is essentially the cyclic dimer of DMAEMA, thus ensuring that the building units of the arms and the core of the star polymers were identical. After their physicochemical characterization, these star-like polyamines were evaluated for their ability to transfer small interfering RNA (siRNA) to murine myoblast cells. Suppression efficiency was found to increase with polymer loading and star branch size, attaining sufficiently high values, comparable to that observed with standard non-viral siRNA transfection systems, while cytotoxicity was kept reasonably low.