Interactions between xanthan gum and phenolic acids.

The molecular and colloidal-level interactions between two major phenolic acids, gallic and caffeic acid, with a major food polysaccharide, xanthan gum, were studied in binary systems aiming to correlate the stability of the binary systems as a function of pH and xanthan-polyphenol concentrations. Global stability diagrams were built, acting as roadmaps for examining the phase separation regimes followed by the fluorimetry-based thermodynamics of the interactions. The effects of noncovalent interactions on the macroscopic behavior of the binary systems were studied, using shear and extensional rheometry.

Microcalorimetry of the intestinal mucus: Hydrogen bonding and self-assembly of mucin.

The effect of mucin hydrogen bonding on the structure of intestinal mucus has been studied with micro-differential scanning mirocalorimetry (μ-DSC), supported by spectroscopy. The experiments were performed in water-dimethyl sulfoxide (DMSO) solutions, using either water-DMSO mixtures of an appropriate DMSO content or water as blanks, as to isolate the effects of the solvent to hydrogen bonding. When using matched water-DMSO blanks, thermal events at low temperatures are linked to the negation of mucin-DMSO interactions, while events at higher temperatures are linked to the break-up of hydrogen bonds connecting the sugars of the individual macromolecules.

Fibrinogen adsorption on zinc oxide nanoparticles: a Micro-Differential Scanning Calorimetry analysis.

Understanding the interactions between proteins and surfaces (nanoparticles or films) is crucial for the fabrication and improvement of biomedical devices in direct contact with human blood. The aim of this work is the study of the interaction of fibrinogen (Fib) with zinc oxide nanoparticles. The nanoparticles were either synthesized chemically or were commercially available, having different size.

Atomic force microscopy probing platelet activation behavior on titanium nitride nanocoatings for biomedical applications.

There is increasing interest in developing novel coatings to enhance the biocompatibility of medical implants. A key issue in biocompatibility research is platelet activation and aggregation on the biomaterials' surface. Stoichiometric and nonstoichiometric titanium nitride (TiN(x)) films were developed by sputtering as case study materials, for probing platelet activation behavior onto them.

Impact of surface electric properties of carbon-based thin films on platelets activation for nano-medical and nano-sensing applications.

Electric surface properties of biomaterials, playing key role to various biointerfacial interactions, were related to hemocompatibility and biosensing phenomena. In this study, the examination of surface electric properties of amorphous hydrogenated carbon thin films (a-C:H) was carried out by means of electrostatic force microscope (EFM) and observation of differences in spatial charge distribution on the surface of the examined films during platelets adhesion was made. The thrombogenic potential of a-C:H thin films developed by magnetron sputtering with approximately 42% sp(3) content and hydrogen partial pressure during deposition was evaluated, by in situ observation with atomic force microscope (AFM) of platelets' activation and their subsequent adhesion.