Journal Article

PreJuSER-18193

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Colloidal Structure and Stability of DNA/Polycations Polyplexes investigated by Small Angle Scattering

Prevost, S. ; Riemer, S. ; Fischer, W. ; Haag, R. ; Böttcher, C. ; Gummel, J. ; Grillo, I. ; Appavou, M.-S.FZJ* ; Gradzielski, M.

2011
American Chemical Soc. Columbus, Ohio

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Please use a persistent id in citations: doi:10.1021/bm201184w

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.

Keyword(s): Colloids: chemistry (MeSH) ; DNA: chemistry (MeSH) ; DNA: metabolism (MeSH) ; DNA: ultrastructure (MeSH) ; Polyamines: chemistry (MeSH) ; Polymers: chemistry (MeSH) ; Scattering, Small Angle (MeSH) ; Health and Life (1st) ; Health and Life (1st) ; Soft Condensed Matter (2nd) ; Colloids ; Polyamines ; Polymers ; polycations ; pentaethylenehexamine ; DNA ; J

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.

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Contributing Institute(s):

1. Neutronenstreuung (ICS-1)
2. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
3. Neutronenstreuung (JCNS-1)
4. Streumethoden (JCNS-2)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)
2. Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) (P55)

Experiment(s):

1. KWS-2: Small angle scattering diffractometer (NL3ao)

Appears in the scientific report 2011

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