title: Plasmid DNA encapsulation within cationic diblock copolymer vesicles for gene delivery.
abstract: We report the design and structural characterization of cationic diblock copolymer vesicles loaded with plasmid DNA based on a single emulsion technique. For this purpose, a DNA solution was emulsified in an organic solvent and stabilized by an amphiphilic diblock copolymer. The neutral block forms an interfacial brush, whereas the cationic attachment complexes with DNA. A subsequent change of the quality of the organic solvent results in the collapse of the brush and the formation of a capsule. The capsules are subsequently dispersed in aqueous medium to form vesicles and stabilized with an osmotic agent in the external phase. Inside the vesicles, the plasmid is compacted in a liquid-crystalline fashion as shown by the appearance of birefringent textures under crossed polarizers and the increase in fluorescence intensity of labeled DNA. The compaction efficiency and the size distribution of the vesicles were determined by light and electron microscopy, and the integrity of the DNA after encapsulation and subsequent release was confirmed by gel electrophoresis. We demonstrate reverse transfection of in vitro cultured HeLa cancer cells growing on plasmid-copolymer vesicles deposited on a glass substrate.
authors.affiliation: Leiden Institute of Chemistry, Leiden University, P. O. Box 9502, 2300 RA Leiden, The Netherlands.
authors.forename: A V
authors.initials: AV
authors.lastname: Korobko
authors.forename: C
authors.initials: C
authors.lastname: Backendorf
authors.forename: J R C
authors.initials: JR
authors.lastname: van der Maarel
mesh_terms: D002412:Cations; D002463:Cell Membrane Permeability; D004247:DNA / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics; D004355:Drug Stability; D004655:Emulsions; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008858:Microscopy, Phase-Contrast; D008859:Microscopy, Polarization; D010957:Plasmids / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics; D011145:Polyvinyls / Q000737:chemistry*; D014162:Transfection
chemical_list: D002412:Cations; D004655:Emulsions; D011145:Polyvinyls; C485184:enhanced green fluorescent protein; C521575:poly(butadiene-b-N-methyl-4-vinylpyridinium iodide); D049452:Green Fluorescent Proteins; D004247:DNA