title: Amphiphilic and biodegradable hy-PEI-g-PCL-b-PEG copolymers efficiently mediate transgene expression depending on their graft density.
abstract: Novel biodegradable amphiphilic copolymers hy-PEI-g-PCL-b-PEG were prepared by grafting PCL-b-PEG chains onto hyper-branched poly(ethylene imine) as non-viral gene delivery vectors. Our investigations focused on the influence of graft densities of PCL-b-PEG chains on physico-chemical properties, DNA complexation and transfection efficiency. We found that the transfection efficiencies of these polymers increased at first towards an optimal graft density (n=3) and then decreased. The buffer-capacity-test showed almost exactly the same tendency as transfection efficiency. Cytotoxicity (MTT-assay) depended on the cooperation of PEG molecular weight and graft density of PCL-b-PEG chains. With increasing the graft density, cytotoxicity, zeta-potential, affinity with DNA, stability of the polyplexes and CMC-values were reduced strongly and regularly. Increasing the excess of polymer over DNA was shown to result in a decrease of the observed particle size to 100-200 nm.
authors: Department of Pharmaceutics and Biopharmacy, Philipps-Universität, Ketzerbach 63, D-35032 Marburg, Germany.
authors: Mengyao
authors: M
authors: Zheng
authors: Yu
authors: Y
authors: Liu
authors: Olga
authors: O
authors: Samsonova
authors: Thomas
authors: T
authors: Endres
authors: Olivia
authors: O
authors: Merkel
authors: Thomas
authors: T
authors: Kissel