The characteristics and transfection efficiency of cationic poly (ester-co-urethane) - short chain PEI conjugates self-assembled with DNA

To improve the transfection efficiency of polycations with DNA, we synthesized poly(ester-co-urethane)(PEU-g-PE1800) with short chain PE1800 in the side chain, and poly(ester-co-urethane)(PEU) without short chain PE1800. Both PEU-g-PE1800 and PEU, readily self-assembled with plasmid DNA (pCMV-beta gal) in a HEPES buffer, were characterized by dynamic light scattering and zeta-potential. The results reveal that PEU-g-PE1800 and PEU were able to self-assemble particles with DNA and yield nano-sized complexes (<200 nm) with positive charge at N/P ratios of 20/1 and 120/1, respectively. The degradation studies indicate that the half-life of PEU-g-PE1800 and PEU in the HEPES buffer were 14 and 35 h at pH 7.4, respectively. Titration studies were performed to determine the buffering capacities of the polymers. The COS-7 cell viabilities in the presence of PEU-g-PE1800/DNA, PEU/DNA, and PE125k/DNA were studied. In addition, The PEU-g-PE1800/DNA complexes were able to transfect COS-7 cells in vitro with a high efficiency comparable to a well-known gene carrier PE125k. The results indicate that PEU-g-PE1800 is an attractive cationic poly (ester-co-urethane) for gene delivery and an interesting candidate for further study. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.