The interaction of plant polysaccharides with collagen

Abstract

This thesis examines the interaction of several plant polysaccharides with bovine collagen and the effect of these interactions on the physical characteristics of biopolymer wound dressings. Recent research in the field of wound healing has led to the development of biological wound dressings such as Fibracol ™, Sorbsan ™, E.Z.Derm ™, Biobrane ™ which contain protein and/or polysaccharides. When these materials are placed on an open wound the potential exists for soluble polysaccharide to diffuse from the dressing into the wound environment. This may alter the rate and quality of wound healing. Therefore, it is important to understand how the protein/polysaccharide interactions and other physical characteristics affect this diffusion. Initially the rheology and co-precipitation of collagen/polysaccharide solutions were studies to determine any polysaccharides which were interacting with collagen. Polysaccharides of interest were then studies in an insoluble system by forming polysaccharide/fibrous collagen wound dressing materials. The effect of different polysaccharides, their charge density, degree of polymerisation, chemical composition, and ionic crosslinking, on the diffusion of molecules from the wound dressing materials were studied. The tensile strength and the absorbency of these materials were also studied. In addition, the effect of different collagen (soluble, insoluble, denatured and chemically modified) were investigated. It was found that the degree of polymerization and chemical composition of the polysaccharide, and the form of collagen used to produce the materials influenced the amount of polysaccharide that was eluted from the material. Calcium ions were also shown to significantly reduce the level of diffusion in materials containing alginate. It appears that the rate and extent of diffusion is controlled by a combination of polymer entrapment and specific polymer-polymer interactions. Different polysaccharides were shown to have no significant effect on either the absorbency or tensile strength of the materials, therefore, it can be concluded that most of the physical characteristics are imparted by the collagen matrix. In summary the results obtained from this work have led to a greater understanding of the factors which control the release of polysaccharides from collagen/polysaccharide composite materials and have given some insight into how the rate of diffusion may be altered to suit a particular application