title: Synthesis, characterization, and evaluation as transfection reagents of double-hydrophilic star copolymers: effect of star architecture.
abstract: Five star polymers of the ionizable hydrophilic 2-(dimethylamino)ethyl methacrylate (DMAEMA) and the nonionic hydrophilic methoxy hexa(ethylene glycol) methacrylate (HEGMA) were prepared by group transfer polymerization (GTP) using ethylene glycol dimethacrylate (EGDMA) as coupling agent. In particular, four isomeric star copolymers, one heteroarm, two star block and one statistical star, with 90% mol DMAEMA and 10% mol HEGMA, plus one star homopolymer of DMAEMA with degrees of polymerization of the arms equal to 20 were synthesized. The polymers were characterized in terms of their molar masses (MMs) and compositions using gel permeation chromatography (GPC) and proton nuclear magnetic resonance (1H NMR) spectroscopy, respectively. The hydrodynamic diameters in water indicated some aggregation for all the star polymers except for the statistical copolymer star, while the pK values of the DMAEMA units were around 7 for all star polymers. All the star polymers were evaluated for their ability to transfect human cervical HeLa cancer cells with the modified plasmid pRLSV40 bearing the enhanced green fluorescent protein (EGFP) as the reporter gene. All four star copolymers showed decreased toxicity compared to that of the DMAEMA star homopolymer for the same amounts of star polymer tested. The star block copolymer with outer DMAEMA blocks exhibited the highest overall transfection efficiency, 11%, compared to that of all the star polymers examined in this study. This efficiency was the same as that of the commercially available transfection reagent SuperFect.
authors.affiliation: Department of Chemistry, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus, Department of Materials Science and Technology, University of Crete, P.O. Box 2208, 710 03 Heraklion, Crete, Greece.
authors.forename: Theoni K
authors.initials: TK
authors.lastname: Georgiou
authors.forename: Maria
authors.initials: M
authors.lastname: Vamvakaki
authors.forename: Leonidas A
authors.initials: LA
authors.lastname: Phylactou
authors.forename: Costas S
authors.initials: CS
authors.lastname: Patrickios
mesh_terms: D001671:Biochemistry / Q000379:methods; D001672:Biocompatible Materials / Q000737:chemistry*; D002850:Chromatography, Gel; D004247:DNA / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005026:Ethylene Glycols / Q000737:chemistry*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008689:Methacrylates / Q000737:chemistry*; D008956:Models, Chemical; D009391:Nephelometry and Turbidimetry; D010957:Plasmids / Q000378:metabolism; D011108:Polymers / Q000737:chemistry*; D012542:Scattering, Radiation; D014162:Transfection; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D005026:Ethylene Glycols; D046911:Macromolecular Substances; D008689:Methacrylates; D011108:Polymers; C507588:hydrophilic methoxy hexa(ethylene glycol) methacrylate; D014867:Water; D049452:Green Fluorescent Proteins; C004919:ethylene dimethacrylate; D004247:DNA; C049840:2-(dimethylamino)ethyl methacrylate