Rapid confocal imaging of vesicle-to-sponge phase droplet transition in dilute dispersions of the CE surfactant.

The lamellar-to-sponge phase transition of fluorescently labelled large unilamellar vesicles (LUVs) of the non-ionic surfactant triethylene glycol mono n-decyl ether (CE) was investigated in situ by confocal laser scanning microscopy (CLSM). Stable dispersions of micrometer-sized CE LUVs were prepared at 20 °C and quickly heated at different temperatures close to the lamellar-to-sponge phase transition temperature. Phase transition of the strongly fluctuating individual vesicles into micrometre-sized sponge phase droplets was observed to occur via manyfold multilamellar morphologies with increasing membrane confinement through inter- and intra- lamellar fusion.

Interaction of jack bean (Canavalia ensiformis) urease and a derived peptide with lipid vesicles.

Ureases are metalloenzymes that catalyze the hydrolysis of urea to ammonia and carbon dioxide. Jack bean (Canavalia ensiformis) produces three isoforms of urease (Canatoxin, JBU and JBURE-II). Canatoxin and JBU display several biological properties independent of their ureolytic activity, such as neurotoxicity, exocytosis-inducing and pro-inflammatory effects, blood platelets activation, insecticidal and antifungal activities.

Scraping and stapling of end-grafted DNA chains by a bioadhesive spreading vesicle to reveal chain internal friction and topological complexity.

Stained end-grafted DNA molecules about 20 μm long are scraped away and stretched out by the spreading front of a bioadhesive vesicle. Tethered biotin ligands bind the vesicle bilayer to a streptavidin substrate, stapling the DNAs into frozen confinement paths. Image analysis of the stapled DNA gives access, within optical resolution, to the local stretching values of individual DNA molecules swept by the spreading front, and provides evidence of self-entanglements.

Spreading of bio-adhesive vesicles on DNA carpets.

Cell-adhesion events involve often the formation of a contact region between phospholipid membranes decorated with a variety of bio-macromolecular species. We mimic here such hairy bio-adhesive contact zones by spreading phospholipid vesicles onto surfaces carpeted with end-grafted λ-phage DNA. Our study reveals that the spreading front acts as a scraper that strongly stretches the DNA molecules, and that the multiple bonds created during vesicle spreading effectively staple the stretched chains in the gap between the membrane and the substrate.