Bioreducible crosslinked low molecular weight branched PEI-PBLG as an efficient gene carrier

Low molecular weight polyethylenimine-poly(gamma-benzyl L-glutamate) (PEI-PBLG) was crosslinked by N,N'-cystamine-bisacrylamide (CBA) to get the polymer named as CBA-PEI-PBLG (CPP). CPP not only inherits PEI-PBLG's amphiphilic advantages, but also possesses reducible properties. CPP can complex with DNA to form nanoparticles. CPP/DNA complex particles were characterized by particle size and zeta potential analysis. The result showed that the complex particles have suitable size and surface charges for gene delivery. And gel retardation assay also prove CBA-PEI-PBLG has proper condensing ability for DNA. CPP has good reducible property, and also has good biocompatibility because of introducing PBLG segment. The cytotoxicity of CPP was evaluated using MTT assay, and the results showed CPP has lower cytotoxicity compared with PEI 25 K. The transfection properties were characterized in different cells by using plasmid DNA as a reporter. CPP showed higher transfection efficiencies and lower cytotoxicity in HeLa cells. This was attributed to bioreducible and biocompatibility properties of the CPP. These results suggested that CPP is a promising low-toxic, highly effective non-viral gene carrier.