Abstract
New polyurethane 2‐diethylaminoethylamine‐polyurethane (LGEA‐PU) containing poly(ethylene glycol) segments and tertiary amines was synthesized. LGEA‐PU self‐assembled readily with the plasmid DNA (pCMV‐βgal) in HEPES buffer and was characterized by dynamic light scattering, zeta potential, atomic force microscopy, and XTT cell viability assays. To examine the effect of molecular weight of LGEA‐PU systems on transfection, LGEA‐PU systems of four different molecular weights (LGEA‐PU99, LGEA‐PU59, LGEA‐PU24, and LGEA‐PU7) were prepared. This study found that LGEA‐PU99, LGEA‐PU59, and LGEA‐PU24 were able to bind plasmid DNA and yielded positively charged complexes with a nano‐sized transfection (<200 nm). The LGEA‐PU59/DNA complexes were able to transfect COS‐7 cells in vitro with higher transfection efficiency than the other LGEA‐PU systems. These results demonstrated that molecular weights of LGEA‐PU systems had a significant effect on transferring ability, except for LGEA‐PU99, which showed the strongest DNA condensation. Examination of the cytotoxicity of PEI and LGEA‐PU systems revealed that LGEA‐PU systems had lower cytotoxicity. In this article, LGEA‐PU59 seemed to be a novel cationic polyurethane for gene delivery and an interesting candidate for further study. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006