Effect of potential drugs on model membranes - An AFM study

Poster (2005)

Effects of bioactive amphiphiles on model cell membranes

in 11th W. Mejbaum-Katzenellenbogen's Molecular Biology Seminar: amphiphiles and their aggregates in basic and applied science (2005)

Nanoscale Properties Of Mixed Fengycin/Ceramide Monolayers Explored Using Atomic Force Microscopy

in Langmuir (2005), 21(6),

To gain insight into the interactions between fengycin and skin membrane lipids, mixed fengycin/ceramide monolayers were investigated using atomic force microscopy (AFM) (monolayers supported on mica) and ... [more ▼]

To gain insight into the interactions between fengycin and skin membrane lipids, mixed fengycin/ceramide monolayers were investigated using atomic force microscopy (AFM) (monolayers supported on mica) and surface pressure-area isotherms (monolayers at the air-water interface). AFM topographic images revealed phase separation in mixed monolayers prepared at 20 °C/pH 2 and composed of 0.25 and 0.5 fengycin molar ratios, in the form of two-dimensional (2-D) hexagonal crystalline domains of ceramide surrounded by a fengycin-enriched fluid phase. Surface pressure-area isotherms as well as friction and adhesionAFMimages confirmed that the two phases had different molecular orientations: while ceramide formed a highly ordered phase with crystalline chain packing, fengycin exhibited a disordered fluid phase with the peptide ring lying horizontally on the substrate. Increasing the temperature and pH to values corresponding to the skin parameters, i.e., 37 °C/pH 5, was found to dramatically affect the film organization. At low fengycin molar ratio (0.25), the hexagonal ceramide domains transformed into round domains, while at higher ratio (0.5) these were shown to melt into a continuous fengycin/ceramide fluid phase. These observations were directly supported by the thermodynamic analysis (deviation from the additivity rule, excess of free energy) of the monolayer properties at the air-water interface. Accordingly, this study demonstrates that both the environmental conditions (temperature,pH)andfengycin concentration influence the molecular organization of mixed fengycin/ceramide monolayers.Webelieve that the ability to modulate the formation of 2-D domains in the skin membrane may be an important biological function of fengycin, which should be increasingly investigated in future pharmacological research. [less ▲]

Nanoscaleorganization of mixed fengycin/lipid monolayers

Poster (2004)

Study of surfactin penetration into lipid monolayers by using AFM

Poster (2004)

Les lipopeptides de Bacillus subtilis: des biosurfactants à structure particulière présentant des activités biologiques prometteuses

Scientific conference (2004)

Interactions of amphiphilic bioactive molecules with membrane-mimetic systems

Conference (2004)

From renewable vegetable resources to microorganisms: new trends in surfactants

in Comptes Rendus de la Chimie (2004), 7

Des produits foisonnés aux agents anti-infectieux: l'avenir est aux agents tensioactifs naturels

Poster (2003)

Interaction Of Surfactin With Membranes: A Computational Approach

in Langmuir (2003), 19(8),