Specific adsorption of functionalized colloids at the surface of living cells: a quantitative kinetic analysis of the receptor-mediated binding.

This paper presents a statistical experimental study of the adsorption of colloids onto the plasma membrane of living cells mediated by specific ligand-receptor interactions. The colloids consist of lipid multilamellar liposomes (spherulites) functionalized by Shiga toxin B-subunit (STxB), while cells are cervix carcinoma epithelial cells expressing the Shiga toxin receptor, the glycolipid globotriaosyl ceramide (Gb3). The specificity of the colloid adsorption is demonstrated using both confocal microscopy and flow cytometry, while a thorough cytometry study on living cells allows characterizing the kinetics of this specific adsorption.

Intracellular trafficking of Shiga-toxin-B-subunit-functionalized spherulites.

Background Information: Spherulites are multi-lamellar lipidic vesicles that can encapsulate biomolecules and may be used as carriers for drug delivery. STxB (Shiga toxin B-subunit) is known to bind the glycosphingolipid Gb3 (globotriaosyl ceramide), which is overexpressed by various human tumours. After Gb3 binding, the toxin enters the cytoplasm via the retrograde route, bypassing the degrading environment of the late endosomes/lysosomes.

Key role of receptor density in colloid/cell specific interaction: a quantitative biomimetic study on giant vesicles.

This paper presents an experimental study of the adsorption of colloids on model membranes mediated by specific ligand-receptor interactions. The colloids consist of lipid multilamellar liposomes (spherulites) functionalized with the B-subunit of Shiga Toxin (STxB), while the membranes are lipid Giant Unilamellar Vesicles (GUV) containing STxB lipid receptor, Globotriaosylceramide (Gb3). Through confocal microscopy and flow cytometry, we show the specificity of the adsorption.

Confined diffusion of hydrophilic probes inserted in lyotropic lamellar phases.

The dynamic behaviour of three hydrophilic probes (two dyes and one fluorescently-labelled protein) inserted in the water layers of lyotropic lamellar phases has been studied by confocal fluorescence recovery experiments. Two different, ionic (AOT/NaCl/ H(2)O and non-ionic ( C(12)E(5) /hexanol/ H(2)O host systems were studied. The confinement effect has been carefully monitored using the swelling properties of the lamellar phases.

Stability of thin nematic films. Commentary on "Morphology and structure of thin liquid-crystalline films at nematic-isotropic transition" by P. Ziherl and S. Zumer.

We discuss the peculiarity of thin nematic films on solid substrates with a free surface, underlining the differences with what is usually seen in dewetting. We review the thermodynamic basis of the coupled phase/thickness separation that has previously been shown experimentally. We give new experimental evidences for the origin of the coupling force chosen in our previous theoretical model.