title: Characterization of vectors for gene therapy formed by self-assembly of DNA with synthetic block co-polymers.
abstract: Cationic polymers can self-assemble with DNA to form polyelectrolyte complexes capable of gene delivery, although biocompatibility of the complexes is generally limited. Here we have used A-B type cationic-hydrophilic block co-polymers to introduce a protective surface hydrophilic shielding following oriented self-assembly with DNA. Block co-polymers of poly(ethylene glycol)-poly-L-lysine (pEG-pLL) and poly-N-(2-hydroxypropyl)methacrylamide-poly(trimethylammonioethyl methacrylate chloride) (pHPMA-pTMAEM) both show spontaneous formation of complexes with DNA. Surface charge measured by zeta potential is decreased compared with equivalent polycation-DNA complexes in each case. Atomic force microscopy shows that pHPMA-pTMAEM/DNA complexes are discrete spheres similar to those formed between DNA and simple polycations, whereas pEG-pLL/DNA complexes adopt an extended structure. Biological properties depend on the charge ratio of formation. At optimal charge ratio, pEG-pLL/DNA complexes show efficient transfection of 293 cells in vitro, while pHPMA-pTMAEM/DNA complexes are more inert. Both block co-polymer-DNA complexes show only limited cytotoxicity. Careful selection of block co-polymer structure can influence the physicochemical and biological properties of the complexes and should permit design of materials for specific applications, including targeted delivery of genes in vivo.
authors.affiliation: CRC Institute for Cancer Studies, University of Birmingham, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Wolfert
authors.forename: E H
authors.initials: EH
authors.lastname: Schacht
authors.forename: V
authors.initials: V
authors.lastname: Toncheva
authors.forename: K
authors.initials: K
authors.lastname: Ulbrich
authors.forename: O
authors.initials: O
authors.lastname: Nazarova
authors.forename: L W
authors.initials: LW
authors.lastname: Seymour
mesh_terms: D002470:Cell Survival; D002478:Cells, Cultured; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure; D004587:Electrophoresis, Agar Gel; D005696:Galactosidases / Q000235:genetics; D005786:Gene Expression Regulation; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000737:chemistry* / Q000648:ultrastructure*; D006801:Humans; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D011108:Polymers / Q000138:chemical synthesis*; D013499:Surface Properties; D014162:Transfection
chemical_list: D011108:Polymers; D004247:DNA; D005696:Galactosidases