articles Synergistic Effect of Low Cytotoxic Linear Polyethylenimine and Multiarm Polyethylene Glycol: Study of Physicochemical Properties and In Vitro Gene Transfection Ran Namgung,† Jihoon Kim,† Kaushik Singha,† Chun Ho Kim,‡ and Won Jong Kim*,† Department of Chemistry, BK21 Program, Polymer Research Institute, Pohang UniVersity of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea, and Lab of Tissue Engineering, Korea Institute of Radiological and Medical Sciences, 215-4, Gongneung-Dong, Nowon-Gu, Seoul 139-706, Korea Received April 1, 2009; Revised Manuscript Received August 11, 2009; Accepted September 30, 2009
Abstract: Novel star-shaped copolymers consisting of multiarm polyethylene glycol and low molecular weight linear polyethylenimines (MAPEG-LPEIs) with a high transfection efficiency and low cytotoxicity were designed and synthesized as nonviral gene delivery carriers. The cationic polymers were prepared by conjugating low molecular weight linear PEI (2.5 kDa) to six-arm PEG-NHS (10 kDa) in two different compositions. Two copolymers, MAPEG-LPEI3 and MAPEG-LPEI6 with molecular weights of 17.5 kDa and 25 kDa respectively, were synthesized. The MAPEG-LPEI3/pDNA and MAPEG-LPEI6/pDNA polyplexes are stably dispersed in aqueous media with a narrowly distributed size range of 1000 nm) with pDNA, both MAPEGLPEI6 and MAPEG-LPEI3 can condense pDNA effectively into smaller polyplex particles (
