Wound dressings for a proteolytic-rich environment

Wound dressings have experienced continuous and significant changes over the years based on the knowledge of the biochemical events associated with chronic wounds. The development goes from natural materials used to just cover and conceal the wound to interactive materials that can facilitate the healing process, addressing specific issues in non-healing wounds. These new types of dressings often relate with the proteolytic wound environment and the bacteria load to enhance the healing. Recently, the wound dressing research is focusing on the replacement of synthetic polymers by natural protein materials to delivery bioactive agents to the wounds. This article provides an overview on the novel protein-based wound dressings such as silk fibroin keratin and elastin. The improved properties of these dressings, like the release of antibiotics and growth factors, are discussed. The different types of wounds and the effective parameters of healing process will be reviewed

Influence of different collagen species on physico-chemical properties of crosslinked collagen matrices

Collagen-based scaffolds are appealing products for the repair of cartilage defects using tissue engineering strategies. The present study investigated the species-related differences of collagen scaffolds with and without 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide/N-hydroxysuccinimide-crosslinking. Resistance against collagenase digestion, swelling ratio, amino acid sequence, shrinkage temp., ultrastructural matrix morphol., crosslinking d. and stress-strain characteristics were detd. to evaluate the physico-chem. properties of equine- and bovine-collagen-based scaffolds. Three-factor ANOVA anal. revealed a highly significant effect of collagen type, crosslinking and time on degrdn. of the collagen samples by collagenase treatment. Crosslinked equine collagen samples showed a significantly reduced swelling ratio compared to bovine collagen samples. The amino acid compn. of equine collagen revealed a higher amt. of hydroxylysine and lysine. Shrinkage temps. of non-crosslinked samples showed a significant difference between equine (60°) and bovine collagen (57°). Three-factor ANOVA anal. revealed a highly significant effect of collagen type, crosslinking and matrix condition on rupture strength measured by stress-strain anal. The ultrastructure, the crosslinking d. and the strain at rupture between collagen matrixes of both species showed no significant differences. For tissue engineering purposes, the higher enzymic stability, the higher form stability, as well as the lower risk of transmissible disease make the case for considering equine-based collagen. This study also indicates that results obtained for scaffolds based on a certain collagen species may not be transferable to scaffolds based on another, because of the differing physico-chem. properties