Star-Shaped Cationic Polymers by Atom Transfer Radical Polymerization from beta-Cyclodextrin Cores for Nonviral Gene Delivery

摘要

Cationic polymers with low cytotoxicity and high transfection efficiency have attracted considerable attention as nonviral carriers for gene delivery.Herein,well-defined and star-shaped CDPD consisting of beta-CD cores and P(DMAEMA)arms,and CDPDPE consisting of CDPD and P(PEGEEMA)end blocks(where CD=cyclodextrin,P(DMAEMA)=poly(2-(dimethylamino)ethyl methacrylate),P(PEGEEMA)=poly(poly(ethylene glycol)ethyl ether methacrylate))for gene delivery were prepared via atom transfer radical polymerization(ATRP)from the bromoisobutyryl-terminated beta-CD core.The CDPD and CDPDPE exhibit good ability to condense plasmid DNA(pDNA)into 100-200 nm size nanoparticles with positive zeta potentials of 25-40 mV at nitrogen/phosphate(N/P)ratios of 10 or higher.CDPD and CDPDPE exhibit much lower cytotoxicity and higher gene transfection efficiency than high molecular weight P(DMAEMA)homopolymers.A comparison of the transfection efficiencies between CDPD and P(DMAEMA)homopolymer indicates that the unique star-shaped architecture involving the CD core can enhance the gene transfection efficiency.In addition to reducing cytotoxicity,the introduction of a biocompatible P(PEGEEMA)end block to the P(DMAEMA)arms in CDPDPE can further enhance the gene transfection efficiency.