LAUSR

Gene delivery is now a part of our therapeutic arsenal for vaccination and treatments of inherited or acquired diseases. Polymers represent an opportunity to develop new synthetic vectors for gene transfer, with a prerequisite of improved delivery and reduced toxicity compared to existing polymers. Here, we report the synthesis in a two-step's procedure of linear poly(ethylenimine-b-2-isopropyl-2-oxazoline) block copolymers with the linear polyethylenimine (lPEI) block of various molar masses; the molar mass of the poly(2-isopropyl-2-oxazoline) (PiPrOx) block been set to 7 kg.mol-1 . Plasmid DNA condensation is successfully achieved, and in vitro transfection efficiency of the copolymers is at least comparable to that obtained with the lPEI of same molar mass. lPEI-b-PiPrOx block copolymers are however less cytotoxic than their linear counterparts. PiPrOx could be a good alternative to PEG which is often used in drug delivery systems. The grafting of histidine moieties on the lPEI block of lPEI-b-PiPrOx does not provide any real improvement of the transfection efficiency. A weak DNA condensation is observed, due to increased steric hindrance along the lPEI backbone. The low cytotoxicity of lPEI-b-PiPrOx makes of this family a good candidate for future gene delivery developments. This article is protected by copyright. All rights reserved.