Synthesis and evaluation of degradable polyurea block copolymers as siRNA delivery agents

Degradable polyurea block copolymers prepared by diisocyanate chain extension were investigated for use as siRNA delivery agents. This approach enabled the synthesis of polymers with defined molecular weight and architecture. The polymer, reducible PEG-b-multi-(polyhexylurea-co-oligo-l-lysine)-b-PEG, was capable of electrostatically condensing siRNA to form nano-sized polyplexes. These polyplexes were delivered to cells in vitro to achieve green fluorescent protein silencing without toxicity.