Katalin F. Csáki

Synthetic surfactant food additives can cause intestinal barrier dysfunction

In addition to genetic factors and antigen exposure, intestinal barrier dysfunction plays a key role in the pathogenesis of numerous allergic and autoimmune diseases. The hypothesis of this article is that synthetic surfactant food additives (also called emulsifiers) - which are applied in relatively high concentrations in even the most frequently consumed foods -cause increased intestinal permeability, hence they can play a significant role in the increasing incidence of numerous allergic and autoimmune diseases. In many cases the surfactants added to foods are exactly the same as the ones used in pharmaceutics as absorption enhancers. Numerous synthetic surfactant food additives have been shown to increase the intestinal permeability through paracellular and/or transcellular mechanisms and some of them were also shown to inhibit P-glycoprotein. Additionally, based on the general characteristics of surfactants it can be predicted that they decrease the hydrophobicity of the mucus layer, which has also been shown to associate with increased intestinal permeability.

Simultaneous competitive adsorption of polymers from ternary solutions at solid/liquid interfaces

Abstract Individual adsorption and simultaneous competitive adsorption from ternary solutions of uncharged polymers on aqueous dispersions of polystyrene lattices with different particle sizes were studied. The effects of the ratio of the polymers competing in simultaneous adsorption for the particle surfaces, and of the extent of the surface area available for the molecules, respectively, on the adsorption preference were investigated. Based on the experimental results, preferential adsorption parameters for polymers in pairs were established and used as a measure of the affinity of the macromolecules competing for the solid surfaces.

Kinetic effects in mixed polymer layers at particle/solution interfaces: non-equilibrium states of uncharged polymers

Abstract The interfacial processes controlling the structure of mixed adsorption layers of uncharged polymers at particle/solution interfaces were studied. Under equilibrium conditions for simultaneous competitive adsorption from ternary polymer solutions, preferential adsorption parameters for the polymers in pairs have been determined on negatively charged colloidal dispersions and used as a measure of the affinity for surface sites of chemically different polymer molecules. The spatial properties of the interfacial polymer layers after various contact times were investigated by photon correlation spectroscopy (PCS), laser Doppler-electrophoresis (LDE) and at low polymer dosages, by flocculation kinetic measurements. It was found that long-term kinetic effects have a marked effect on the structure of composite interfacial layers. At low surface coverages, competition for partially covered particle surfaces of suitable polymers may lead to the formation of extended mixed adsorption layers. Displacement from the interfaces of the less preferred polymer results in either increase or decrease in time of both the hydrodynamic and the electrophoretic thicknesses in the mixed layers. The non-equilibrium states of the adsorbed macromolecules, existing over much longer period in the mixed layers than in the individual polymer layers, closely correlate to the preferential affinity for surface sites of the competing macromolecules.

Autophobic Wetting and Captation

Not all cases of spreading equilibrium can be described by the Young equation. However, assuming that the wetting is achieved in two steps – the equilibrium state is developed not directly on the solid surface but on the liquid film formed on the solid surface – the Young equation perfectly describes this latter state.

On the Magnitude of Line Tension

It was shown in our analysis of the internal energy determining the state of the capillary system that the magnitude of the intensive and non-canonical line tension depends on the size of the penetrating zone. Therefore, its effect is negligible for macroscopic systems.