Structural investigations of novel triblock cationic copolymer/DNA complexes

摘要

A series of biodegradable triblock copolymers poly (ethylene glycol)-g-polyethylenimine-b-poly (dimethylaminoethyl l-glutamine) (PEG-g-PEI-b-PDMAEG) as novel vectors for gene therapy were synthesized and evaluated.Poly (ethylene glycol)-g-polyethylenimiene (PEG-g-PEI) was firstly obtained by linking of PEG and PEI using isophorone diisocyanate (IPDI) as coupling reagent.The anionic copolymerization of γ-benzyl l-glutamtae N-carboxyanhydride (BLG-NCA) using PEG-g-PEI as a macroinitiator was carried out,followed by aminolysis with 2-dimethylaminoethylamine to obtain the target water soluble triblock copolymer.The structures from PEG-g-PEI precursor to the triblock copolymers were confirmed by FT-IR.The particle sizes,zeta potentials of polyplexes were evaluated.All polyethylenimine derivates were revealed to compact plasmid DNA effectively to give polyplexes with suitable size (～100 nm) and moderate ζ-potentials (10-15 mV) at N/P ratios of 30.The relationship between the composition of PEG-g-PEI-b-PDMAEG and the size,the ζ-potentials of corresponding copolymer/DNA complexes were also investigated.