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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
School of Pharmaceutical Science, Shandong University, 44 Wenhua Xi Road, Ji’nan, 250012 Shandong Province, China
Department of Pharmacy, Shandong Medical College, 5460 Bicyclic Nan Road, Ji’nan, 250002 Shandong Province, China
School of Chemistry and Chemical Engineering, Shandong University, 27 Shanda Road, 250010 Ji’nan, China
These authors contributed equally to this work.
* Author to whom correspondence should be addressed.
Received: 28 December 2010; in revised form: 29 January 2011 / Accepted: 15 February 2011 / Published: 23 February 2011
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 NH2-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 ε-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.
Keywords: PLA-PEG-PLL; nanoparticles; non-viral gene vector; gene transfection; tri-block copolymer
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MDPI and ACS Style
Fu, C.; Sun, X.; Liu, D.; Chen, Z.; Lu, Z.; Zhang, N. 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. Int. J. Mol. Sci. 2011, 12, 1371-1388.
Fu C, Sun X, Liu D, Chen Z, Lu Z, Zhang N. 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. International Journal of Molecular Sciences. 2011; 12(2):1371-1388.
Fu, Chunhua; Sun, Xiaoli; Liu, Donghua; Chen, Zhijing; Lu, Zaijun; Zhang, Na. 2011. "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." Int. J. Mol. Sci. 12, no. 2: 1371-1388.