Ring-Opening Polymerization for Hyperbranched Polycationic Gene Delivery Vectors with Excellent Serum Tolerance

摘要

In order to improve the transfection efficiency (TE) and biocompatibility, we synthesized a series of hyperbranched cationic polymers by ring-opening polymerization between diepoxide and several polyamines. These materials can condense plasmid DNA efficiently into nanoparticles that have much lower cytotoxicity than those derived from bPEL In vitro transfection experiments showed that polymers prepared from branched or cyclic polyamine (PI and P5) exhibited TE several times higher than 25KDa bPEI. More sigmhcantly, serum seemed to have no negative effect on PI—PS mediated transfection. On the contrary, the TE of PI improved, even when the serum concentration reached 70%. Several assays demonstrated the excellent serum tolerance of such polycationic vectors: bovine serum albumin (BSA) adsorption assay revealed considerably lower protein adsorption of PI—PS than PEL; PI showed better DNA protection ability from degradation by DNase I than PEL flow cytometry results suggested that any concentration of serum may not decrease the cellular uptake of Pl/DNA polyplex; and confocal laser scanning microscopy also found that serum has little effect on the transfection. By using specific cellular uptake inhibitors, we found that the polyplexes enter the cells mainly via caveolae and microtubule-mediated pathways. We believe that this ring-opening polymerization may be an effective synthetic approach toward gene delivery materials with high biological activity.