Abstract:

Cryogenic- TEM has long been recognized as an instrumental method for studying the nanostructure of soft materials (e.g., surfactants, lipids, peptides and proteins) at high resolution. The method involves ultra-rapid cooling of liquid suspensions and creation of amorphous, vitrified specimens, which captures the native state of structured liquids thereby allowing to get directly detailed structural information at the nanoscale, as well as to explore self-organization mechanisms and dynamics.

I will briefly review the principles of the two main cryo-TEM technique, direct-imaging and freeze-fracture, and present from our recent studies examples relevant to nanoscience and nanotechnology, including studies with peptide nanotubes [1,2], DNA/lipid systems for gene therapy [3] and oral delivery nano-vehicles [4,5]. 

References:

1.            Ziserman L, Lee HY, Raghavan SR, Mor A, Danino D. Unraveling the Mechanism of Nanotube Formation by Chiral Self-Assembly of Amphiphiles. J Am Chem Soc 133(8), 2511-2517 (2011).

2.            Ziserman L, Mor A, Harries D, and Danino D. Curvature Instability in Chiral Amphiphile
Self-Assembly. Phys Rev Lett 106, 238105 (2011).

3.            Danino D, Kesselman E, Saper G, Petrache H and Harries D. A Lamellar to Hexagonal Phase Transition in DNA/Lipid Complexes Induced by Osmotic Pressure. Biophys J 96(7), L43-45 (2009).

4.            Efrat R, Kesselman E., Aserin A, Garti N and Danino D. Solubilization of hydrophobic guest molecules in the monoolein discontinuous cubic mesophase and its soft nanoparticles.  Langmuir 25(3), 1316-1326 (2009).

5.            Bachar M, Mandelbaum A, Pornaya I, Kesselman E and Danino D. A novel oral drug nanocarrier based on self-assembled beta-casein micelles. (Submitted).