Synthesis and characterization of stearyl protamine and investigation of their complexes with DNA for gene delivery

A novel gene carrier, stearyl protamine (SP) was synthesized by the reaction of natural protamine with an N-hydroxysuccinimide (NHS) ester of stearic acid. This SP was characterized by FT-IR, stearyl content measurement and dynamic light scattering (DLS). Then, the SP was evaluated as a gene delivery carrier. The SP with higher stearyl group content(SP3) can self-assemble into aggregates with an average diameter of ca. 110nm in water and has relatively higher in vitro gene transfection efficiency than protamine and SP with lower stearyl group content. A possible mechanism is proposed for the formation of complex of SP/DNA. The SP also shows a low cytotoxicity similar to protamine. (C) 2009 Elsevier B.V. All rights reserved.