title: Decorated rods: a "bottom-up" self-assembly of monomolecular DNA complexes.
abstract: Fluorescence correlation spectroscopy (FCS) and gel electrophoresis measurements are performed to investigate both the number and size of complexes of linear double-stranded DNA (dsDNA) fragments with 1:1 diblock copolymers consisting of a cationic moiety, branched polyethyleneimine (bPEI) of 2, 10, or 25 kDa, covalently bound to a neutral shielding moiety, poly(ethylene glycol) (PEG; 20 kDa). By systematically decreasing the bPEI length, the PEG grafting density along the DNA chain can be directly controlled. For 25 and 10 kDa bPEI-PEG copolymers, severe aggregation is observed despite the presence of the shielding PEG. Upon decreasing the bPEI length to 2 kDa, controlled self-assembly of monomolecular DNA nanoparticles is observed. The resulting complexes are in quantitative agreement with a theoretical model based on a single DNA encased in a dense PEG polymer brush layer. The resulting PEGylated complexes show high stability against both salt and protein and hence are of potential use for in vivo gene delivery studies.
authors.affiliation: Department of Physics, Ludwig-Maximilians-Universität, D-80539 Munich, Germany. deroucja@mail.nih.gov
authors.forename: Jason
authors.initials: J
authors.lastname: DeRouchey
authors.forename: Greg F
authors.initials: GF
authors.lastname: Walker
authors.forename: Ernst
authors.initials: E
authors.lastname: Wagner
authors.forename: Joachim O
authors.initials: JO
authors.lastname: Rädler
mesh_terms: D004247:DNA / Q000138:chemical synthesis / Q000737:chemistry*; D004058:Diffusion; D004591:Electrophoresis, Polyacrylamide Gel; D046911:Macromolecular Substances / Q000138:chemical synthesis / Q000737:chemistry; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*; D011094:Polyethyleneimine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D046911:Macromolecular Substances; C521156:branched polyethyleneimine-block-polyethylene glycol; D011092:Polyethylene Glycols; D011094:Polyethyleneimine; D004247:DNA