Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 5: Nanoparticles and Composite Materials I (joint CPP/BP)

BP 5.11: Talk

Monday, March 16, 2015, 12:30–12:45, C 243

Nanocomposites of colloidal triglyceride platelets and DNA — •Martin Schmiele, Charlotte Knittel, and Tobias Unruh — Physik Department, Friedrich-Alexander-Universität Erlangen–Nürnberg, Staudtstr. 3, 91058 Erlangen, Germany

Aqueous suspensions of colloidal tripalmitin platelets, stabilized by a mixture of soybean lecithin, Poloxamer 188 (or Polysorbate 80) and the cationic surfactant dioctadecyldimethylammonium bromide (DODAB), are prepared by high-pressure melt homogenization. DODAB provides the platelets with a positive surface charge. DNA complexes are prepared by addition of herring DNA to the suspensions.

The structure of the DNA complexes, ranging from the molecular to the micron scale, is investigated by small- and wide-angle x-ray and neutron scattering, microcalorimetry, photon correlation spectroscopy, transmission electron microscopy and computer simulations.

Complexes prepared from native suspensions with low concentrations of DODAB and high +/− charge ratios (DODAB:DNA) exhibit sizes in the colloidal range. Higher concentrations of DODAB and charge ratios close to the isoelectric point promote platelet agglomeration, leading to very large complexes of several microns.

Small-angle scattering and computer simulations reveal a lamellar arrangement of the platelets in the complexes, with the DNA being most probably sandwiched between the platelets. Such nanocomposites of macromolecules (DNA) and tripalmitin platelets could provide a good protection of the intercalated macromolecules and can be regarded as a potential carrier system for them.