Cryo-transmission electron microscopy

Fast Fonrier Transform cryo-TEM has been found to be a suitable replacement to SAXS to study the nano-structure of microemulsions (Sagalowicz et al, 2006). This technique offers the advantage of being able to study individual particles as well the co-existence of particles with varying structural details in the same sample (Leser et al, 2006 Sagalowicz 

Finally, a novel technique is freeze-fracture direct imaging, where sensitive samples such as microemulsions can be studied without the need for a replica. This technique does not have a blotting step (as per cryo-TEM) that can damage micioemulsion structures (Belkoura et al, 2004 Gradzielski, 2008). 

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Goldraich M, Talmon Y (2000) Direct-imaging cryo-transmission electron microscopy in the study of colloids and polymer solutions. In Alexandridis P, Lindman B (eds) Amphiphilic block copolymers self assembly and applications. Elsevier, Amsterdam... 

Marchin, S., Putaux, J.L., Pignon, F., Leonil, J. (2007). Effects of the environmental factors on the casein micelle structure studied by cryo-transmission electron microscopy and small-angle X-ray scattering/ultra-small-angle X-ray scattering. Journal of Chemical Physics, 126, 45-101. 

Cryo-Transmission Electron Microscopy of Vitreous Skin Sections. 37... 

To better understand the structure, function, and dynamics of the endogenous lipid matrix of the stratum corneum intercellular space some general principles of lipid phase behavior, dynamics, and structural organization may represent a useful starting point. Further follows a short overview of some basic physico-chemical principles that may be of relevance for stratum corneum lipid research, followed by a presentation of the new technique cryo-transmission electron microscopy of fully hydrated vitreous skin sections and how this technique recently has been applied to the study of the structural organization and formation of the lipid matrix of the stratum corneum intercellular space. 

CRYO-TRANSMISSION ELECTRON MICROSCOPY OF VITREOUS SKIN SECTIONS... 

Norlen, L.P.O., Al-Amoudi, A., and Dubochet, J. (2003) A cryo-transmission electron microscopy study of skin barrier formation. J. Invest. Dermatol. 120 555-560. 

Siegel, D. P, Green, W., and Talmon, J. (1989), Intermediates in membrane fusion and bilayer/nonbilayer phase transitions imaged by time-resolved cryo-transmission electron microscopy, Biophys /., 56,161-169. 

Egelhaaf, S.U., Schurtenberger, P., and Muller, M. (2000). New controlled environment vitrification system for cryo-transmission electron microscopy design and application to surfactant solutions. J. Microsc. 200, 128-139. 

Flavanol self-association has been demonstrated by means of NMR (Dufour and Bayonove 1999 Mirabel et al. 1999a) and mass spectrometry (Sarni-Manchado and Cheynier 2002) and their aggregation has been studied by means of dynamic light scattering (Poncet-Legrand et al. 2003 Riou et al. 2002 Saucier et al. 1997a) and cryo-transmission electron microscopy (Poncet-Fegrand et al. 2003). 

Ponsinet, V. and Talmon, Y. (1997) Direct imaging of lamellar phases by cryo-transmission electron microscopy. Langmuir, 13, 7287-7292. 

Belkoura, L., Stubenrauch, C. and Strey, R. (2004) Freeze fracture direct imaging A new freeze fracture method for specimen preparation in cryo-transmission electron microscopy. 

M. Ahngren, K. Edwards, G. Karlsson, Cryo transmission electron microscopy of liposomes and related structures. Colloid Surf. A-Physicochem. Eng. Asp., 2000, 174, 3-21. 

N. Berclaz, Studies on the formation and transformation of protein-containing vesicles using cryo-transmission electron microscopy. Ph.D. dissertation Nr. 13493, ETH Zurich, 1999. 

Structural Analysis of MxA Oligomers by Cryo-transmission Electron Microscopy... 

Boettcher et al. showed that when hot solutions (> 80 °C) of A-dodecanoyl (d- or l-) serine (Figure lOh) in toluene were cooled to room temperature, they produced gels consisting of LNTs and vesicles. Cryo-transmission electron microscopy allowed the first direct comparison of the nanotubes (diameters, 80-130 nm) obtained from the serine-amphiphile derivative under normal and reversed polarity conditions. All the assemblies had similar multilayers with a periodicity of 3.30nm both in water and in toluene. These materials gave normal bilayers with the hydrophilic head groups oriented toward the aqueous environment and inverse bilayers with the alkyl chains oriented toward the hydrophobic toluene phase, respectively. 

D. Danino and Y. Tahnon, Direct-Imaging and Freeze-Fracture Cryo-Transmission Electron Microscopy of Molecular Gels, ChaptCT 9 in Molecular Gels, Materials with... 

Abstract Self-assembly is an important phenomenon that leads to formation of interesting and novel structures in colloidal dispersions. We present experimental evidence for the existence of a cubatic phase in a colloidal dispersion of disc-like particles of nickel hydroxide colloidal dispersions. In this structure, disc-like particles self-assemble as domains of a few parallel discs and the orientation tends to be orthogonal in adjacent domains. This phase has been predicted previously by computer simulations. The domains are approximately equiaxial and are predicted to exist only within a limited range of aspect ratios and volume fractions. We have used the real space technique of cryo-transmission electron microscopy in our studies as this locally ordered structure could not be identified readily using scattering techniques, since the patterns are expected to be similar to those of isotropic liquid phases. 

The endproduct of a nanomaterial sample can be in the form of a solid powder or in solution/suspension. For a dried powder in solution, concentration is easily determined by dispersing a known amount of sample (in grams) into a known amount of solvent (in liters). For the best measurement of particles in solution, cryo-transmission electron microscopy should be used. Usually, a known volume of sample is used when preparing nanoparticles in suspension for cryo-TEM analysis. After images are taken from the sample, the nanoparticles in each micrograph are counted. 

Sagalowicz, L., Michel, M., Adrian, M., Frossard, P., Rouvet, M., Watzke, H. J., Yaghmur, A., de Campo, L., Glatter, O., and Leser, M. E. 2006 Crystallography of dispersed liquid crystalline phases studied by cryo-transmission electron microscopy. J. Microsc., 221, 110-121. 

Microemulsion structure can be observed by electron microscopy (EM). Jahn and Strey (4) were the first to publish reliable electron microscopy images of microemulsions. Their systematic study involved both droplet and bicontinuous structures, using the so-called freeze-fracture technique where a replica of the sample is made which is then monitored by the electron microscope. Another technique, Cryo transmission electron microscopy (Cryo-TEM), is probably less suitable for microemulsions with larger oil contents. In this technique, a thin slice of the sample is directly monitored... 

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