Decorated rods: a "bottom-up" self-assembly of monomolecular DNA complexes.
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.
DeRouchey
Jason
J
Department of Physics, Ludwig-Maximilians-Universität, D-80539 Munich, Germany. deroucja@mail.nih.gov
Walker
Greg F
GF
Wagner
Ernst
E
Rädler
Joachim O
JO
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
D046911:Macromolecular Substances; C521156:branched polyethyleneimine-block-polyethylene glycol; D011092:Polyethylene Glycols; D011094:Polyethyleneimine; D004247:DNA