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@ARTICLE{Prevost:18193,
      author       = {Prevost, S. and Riemer, S. and Fischer, W. and Haag, R. and
                      Böttcher, C. and Gummel, J. and Grillo, I. and Appavou,
                      M.-S. and Gradzielski, M.},
      title        = {{C}olloidal {S}tructure and {S}tability of
                      {DNA}/{P}olycations {P}olyplexes investigated by {S}mall
                      {A}ngle {S}cattering},
      journal      = {Biomacromolecules},
      volume       = {12},
      issn         = {1525-7797},
      address      = {Columbus, Ohio},
      publisher    = {American Chemical Soc.},
      reportid     = {PreJuSER-18193},
      pages        = {4272},
      year         = {2011},
      note         = {For allocation of SANS and SAXS beam times, we are grateful
                      to the HZB, ILL, JCNS, and ESRF. For help with the
                      scattering experiments, we would like to thank T. Narayanan
                      (ESRF, ID2). For her constant help during the SANS and SAXS
                      measurements, we are indebted to P. Heunemann. N. Graeber
                      and A. Walther are thanked for preparation of samples. SANS
                      experiments at the HZB and JCNS have been supported by the
                      European Commission under the 7th Framework Program through
                      the Key Action: Strengthening the European Research Area,
                      Research Infrastructures, Contract No. 226 507 (NMI3). The
                      research project has been supported and funded by the SFB
                      448 of the Deutsche Forschungsgemeinschaft.},
      abstract     = {Polyplexes of short DNA-fragments (300 b.p., 100 nm) with
                      tailor-made amine-based polycations of different
                      architectures (linear and hyperbranched) were investigated
                      in buffer solution as a function of the mixing ratio with
                      DNA. The resulting dispersed polyplexes were characterized
                      using small-angle neutron and X-ray scattering (SANS, SAXS)
                      as well as cryo-TEM with respect to their mesoscopic
                      structure and their colloidal stability. The linear
                      polyimines form rather compact structures that have a high
                      tendency for precipitation. In contrast, the hyperbranched
                      polycation with enzymatic-labile pentaethylenehexamine arms
                      (PEHA) yields polyplexes colloidally stable for months. Here
                      the polycation coating of DNA results in a homogeneous
                      dispersion based on a fractal network with low structural
                      organization at low polycation amount. With increasing
                      polycation, bundles of tens of aligned DNA rods appear that
                      are interconnected in a fractal network with a typical
                      correlation distance on the order of 100 nm, the average
                      length of the DNA used. With higher organization comes a
                      decrease in stability. The 3D network built by these beams
                      can still exhibit some stability as long as the material
                      concentration is large enough, but the structure collapses
                      upon dilution. SAXS shows that the complexation does not
                      affect the local DNA structure. Interestingly, the
                      structural findings on the DNA polyplexes apparently
                      correlate with the transfection efficiency of corresponding
                      siRNA complexes. In general, these finding not only show
                      systematic trends for the colloid stability, but may allow
                      for rational approaches to design effective transfection
                      carriers.},
      keywords     = {Colloids: chemistry / DNA: chemistry / DNA: metabolism /
                      DNA: ultrastructure / Polyamines: chemistry / Polymers:
                      chemistry / Scattering, Small Angle / Colloids (NLM
                      Chemicals) / Polyamines (NLM Chemicals) / Polymers (NLM
                      Chemicals) / polycations (NLM Chemicals) /
                      pentaethylenehexamine (NLM Chemicals) / DNA (NLM Chemicals)
                      / J (WoSType)},
      cin          = {ICS-1 / JCNS (München) ; Jülich Centre for Neutron
                      Science JCNS (München) ; JCNS-FRM-II / JCNS-1 / JCNS-2},
      ddc          = {540},
      cid          = {I:(DE-Juel1)ICS-1-20110106 /
                      I:(DE-Juel1)JCNS-FRM-II-20110218 /
                      I:(DE-Juel1)JCNS-1-20110106 / I:(DE-Juel1)JCNS-2-20110106},
      pnm          = {BioSoft: Makromolekulare Systeme und biologische
                      Informationsverarbeitung / Großgeräte für die Forschung
                      mit Photonen, Neutronen und Ionen (PNI)},
      pid          = {G:(DE-Juel1)FUEK505 / G:(DE-Juel1)FUEK415},
      experiment   = {EXP:(DE-MLZ)KWS2-20140101},
      shelfmark    = {Biochemistry $\&$ Molecular Biology / Chemistry, Organic /
                      Polymer Science},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:22074384},
      UT           = {WOS:000297782100013},
      doi          = {10.1021/bm201184w},
      url          = {https://juser.fz-juelich.de/record/18193},
}