Investigating the interactions of hyaluronan derivatives with biomolecules. The use of diffusional NMR techniques

[Chemical structure: see text] The interactions between a biomaterial and biomolecules present in body fluids often determine the fate of the biomaterial. This paper presents a study on hyaluronan (HA)-containing materials (in soluble or colloidal form) that focuses on their interactions with lipids and proteins and for the first time uses PFG NMR as an analytical technique for probing these events. The interactions of HA-based polymers with phospholipids (DPPC and DPPG liposomes) are shown to depend both on charge and hydrophobicity factors. Despite the difference in behavior between albumin (substantially non-adhesive) and fibrinogen (adhesive), the interactions of the polymers with proteins do not seem to be based on hydrophobic effects but on surface polar interactions.     

Thermal Methods of Organic Matter Maturation Monitoring During a Composting Process

The possibility to use thermal analysis for a quick characterisation of chemical changes in the organic matter of composted materials was tested. Nine samples were taken at progressive stages of maturation from the same trench of a fully automated composting plant. DSC and TG were simultaneously performed in static air conditions on whole ground composts. Progressive stages in the composting process yielded samples whose DSC traces revealed appreciable modifications in thermal patterns that agreed well with quantitative data obtained from TG measurements. The ratio between the mass losses associated with the two main exothermic reactions (R1) showed a good sensitivity in detecting the changes in the level of stabilisation during the composting process. Thermal methods seem to be a valid comparative method in evaluating the level of bio-transformation of materials during a composting process. This revised version was published online in July 2006 with corrections to the Cover Date.