title: Effects of incorporation of poly(gamma-glutamic acid) in chitosan/DNA complex nanoparticles on cellular uptake and transfection efficiency.
abstract: Chitosan (CS)/DNA complex nanoparticles (NPs) have been considered as a vector for gene delivery. Although advantageous for DNA packing and protection, CS-based complexes may lead to difficulties in DNA release once arriving at the site of action. In this study, an approach through modifying their internal structure by incorporating a negatively charged poly(gamma-glutamic acid) (gamma-PGA) in CS/DNA complexes (CS/DNA/gamma-PGA NPs) is reported. The analysis of small angle X-ray scattering results revealed that DNA and gamma-PGA formed complexes with CS separately to yield two types of domains, leading to the formation of "compounded NPs". With this internal structure, the compounded NPs might disintegrate into a number of even smaller sub-particles after cellular internalization, thus improving the dissociation capacity of CS and DNA. Consequently, after incorporating gamma-PGA in CS/DNA complexes, a significant increase in their transfection efficiency was found. Interestingly, in addition to improving the release of DNA intracellularly, the incorporation of gamma-PGA in CS/DNA complexes significantly enhanced their cellular uptake. We further demonstrated that besides a non-specific charged-mediated binding to cell membranes, there were specific trypsin-cleavable proteins involved in the internalization of CS/DNA/gamma-PGA NPs. The aforementioned results indicated that gamma-PGA played multiple important roles in enhancing the cellular uptake and transfection efficiency of CS/DNA/gamma-PGA NPs.
authors.affiliation: Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan, ROC.
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Peng
authors.forename: Mei-Ju
authors.initials: MJ
authors.lastname: Yang
authors.forename: Chun-Jen
authors.initials: CJ
authors.lastname: Su
authors.forename: Hsin-Lung
authors.initials: HL
authors.lastname: Chen
authors.forename: Po-Wei
authors.initials: PW
authors.lastname: Lee
authors.forename: Ming-Cheng
authors.initials: MC
authors.lastname: Wei
authors.forename: Hsing-Wen
authors.initials: HW
authors.lastname: Sung
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival; D048271:Chitosan / Q000737:chemistry*; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure; D004587:Electrophoresis, Agar Gel; D015870:Gene Expression; D006801:Humans; D018613:Microscopy, Confocal; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010957:Plasmids / Q000648:ultrastructure; D011099:Polyglutamic Acid / Q000737:chemistry*; D053838:Scattering, Small Angle; D014162:Transfection; D014961:X-Ray Diffraction
chemical_list: D011099:Polyglutamic Acid; D004247:DNA; D048271:Chitosan