title: Biodegradable tri-block copolymer poly(lactic acid)-poly(ethylene glycol)-poly(l-lysine)(PLA-PEG-PLL) as a non-viral vector to enhance gene transfection.
abstract: Low cytotoxicity and high gene transfection efficiency are critical issues in designing current non-viral gene delivery vectors. The purpose of the present work was to synthesize the novel biodegradable poly (lactic acid)-poly(ethylene glycol)-poly(l-lysine) (PLA-PEG-PLL) copolymer, and explore its applicability and feasibility as a non-viral vector for gene transport. PLA-PEG-PLL was obtained by the ring-opening polymerization of Lys(Z)-NCA onto amine-terminated NH(2)-PEG-PLA, then acidolysis to remove benzyloxycarbonyl. The tri-block copolymer PLA-PEG-PLL combined the characters of cationic polymer PLL, PLA and PEG: the self-assembled nanoparticles (NPs) possessed a PEG loop structure to increase the stability, hydrophobic PLA segments as the core, and the primary ɛ-amine groups of lysine in PLL to electrostatically interact with negatively charged phosphate groups of DNA to deposit with the PLA core. The physicochemical properties (morphology, particle size and surface charge) and the biological properties (protection from nuclease degradation, plasma stability, in vitro cytotoxicity, and in vitro transfection ability in HeLa and HepG2 cells) of the gene-loaded PLA-PEG-PLL nanoparticles (PLA-PEG-PLL NPs) were evaluated, respectively. Agarose gel electrophoresis assay confirmed that the PLA-PEG-PLL NPs could condense DNA thoroughly and protect DNA from nuclease degradation. Initial experiments showed that PLA-PEG-PLL NPs/DNA complexes exhibited almost no toxicity and higher gene expression (up to 21.64% in HepG2 cells and 31.63% in HeLa cells) than PEI/DNA complexes (14.01% and 24.22%). These results revealed that the biodegradable tri-block copolymer PLA-PEG-PLL might be a very attractive candidate as a non-viral vector and might alleviate the drawbacks of the conventional cationic vectors/DNA complexes for gene delivery in vivo.
authors.affiliation: Department of Pharmacy, Shandong Medical College, 5460 Bicyclic Nan Road, Ji'nan, 250002 Shandong Province, China; E-Mail: Chunhua@163.com (C.F.).
authors.forename: Chunhua
authors.initials: C
authors.lastname: Fu
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Sun
authors.forename: Donghua
authors.initials: D
authors.lastname: Liu
authors.forename: Zhijing
authors.initials: Z
authors.lastname: Chen
authors.forename: Zaijun
authors.initials: Z
authors.lastname: Lu
authors.forename: Na
authors.initials: N
authors.lastname: Zhang
mesh_terms: D063566:Biodegradable Plastics / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D004247:DNA / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry; D011091:Polyesters / Q000737:chemistry* / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000494:pharmacology; D011107:Polylysine / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000494:pharmacology; D014162:Transfection / Q000379:methods*
chemical_list: D063566:Biodegradable Plastics; D011091:Polyesters; C542623:monomethoxypolyethyleneglycol-polylactide block copolymer; C000594643:poly(lactic acid)-poly(ethylene glycol)-poly(lysine); D011107:Polylysine; D011092:Polyethylene Glycols; D004247:DNA