Interfacial Characterization of Ruthenium-Based Amphiphilic Photosensitizers.

Nonreactive surfactant molecules have long been used and characterized for a wide range of applications in industries, life science, and everyday life. Recently, new types of functional amphiphilic molecules have emerged that bear another function, for example, a light-absorbing action, or catalytic properties. However, the surfactant properties of these molecules remain to date essentially unknown.

Microfluidic thin film pressure balance for the study of complex thin films.

Investigations of free-standing liquid films enjoy an increasing popularity due to their relevance for many fundamental and applied scientific problems. They constitute soap bubbles and foams, serve as membranes for gas transport or as model membranes in biophysics. More generally, they provide a convenient tool for the investigation of numerous fundamental questions related to interface- and confinement-driven effects in soft matter science.

Modulation of bacterial multicellularity via spatio-specific polysaccharide secretion.

The development of multicellularity is a key evolutionary transition allowing for differentiation of physiological functions across a cell population that confers survival benefits; among unicellular bacteria, this can lead to complex developmental behaviors and the formation of higher-order community structures. Herein, we demonstrate that in the social δ-proteobacterium Myxococcus xanthus, the secretion of a novel biosurfactant polysaccharide (BPS) is spatially modulated within communities, mediating swarm migration as well as the formation of multicellular swarm biofilms and fruiting bodies. BPS is a type IV pilus (T4P)-inhibited acidic polymer built of randomly acetylated β-linked tetrasaccharide repeats.

Interfacial Properties of N, an Intrinsically Disordered Protein.

Intrinsically disordered proteins (IDPs) lack stable secondary and tertiary structure under physiological conditions in the absence of their biological partners and thus exist as dynamic ensembles of interconverting conformers, often highly soluble in water. However, in some cases, IDPs such as the ones involved in neurodegenerative diseases can form protein aggregates and their aggregation process may be triggered by the interaction with membranes. Although the interfacial behavior of globular proteins has been extensively studied, experimental data on IDPs at the air/water (A/W) and water/lipid interfaces are scarce.

Microbubbles with a Self-Assembled Poloxamer Shell and a Fluorocarbon Inner Gas.

The numerous applications of microbubbles in food science and medicine call for a better understanding and control of the effects of the properties of their shells on their stability and ability to resonate at chosen frequencies when submitted to an ultrasound field. We have investigated both millimetric and micrometric bubbles stabilized by an amphiphilic block copolymer, Poloxamer 188 (e.g.

A study of dilational rheological properties of polymers at interfaces.

Viscoelastic properties of two polymers, partially hydrolyzed polyacrylamide and partially hydrolyzed modified polyacrylamide, widely used in chemical flooding in the petroleum industry, were investigated at three interfaces, water-air, water-dodecane, and water-crude oil, by means of a dilational method provided by I.T. Concept, France, at 85 degrees C.

Transfer of orlistat through oil-water interfaces.

The transfer of radiolabelled orlistat ([14C]orlistat), a potent gastrointestinal lipase inhibitor, through an oil-water interface from a single oil droplet to an aqueous phase was investigated, using an oil drop tensiometer. The absolute transfer fluxes were found to be very low, even in the presence of micellar concentrations of bile salts, which increased their values from 0.2 to 2.