|Brown, Eleanor - Ellie|
Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2004
Publication Date: 5/1/2005
Citation: Lastowka, A.M., Brown, E.M., Maffia, G.J. 2005. A comparison of chemical, physical and enzymatic cross-linking of bovine type i collagen fibrils. Journal of American Leather Chemists Association. 100(5):196-202. Interpretive Summary: Bovine corium, a by-product of the leather industry, is an economical source of collagen, a protein useful for applications in biotechnology including artificial organ scaffolding and skin grafts. To prepare collagen for these applications, the protein chains can be bonded, or cross-linked together. Cross-links are beneficial since they increase molecular size, mechanical strength, and structural stability of the protein. In this study, chemical, physical, and enzymatic methods were used to cross-link collagen. All treatments increased the size of the collagen aggregates. Chemical crosslinking, using glutaraldehyde, produced large, stable molecular complexes. Dehydrothermal drying, a physical treatment, fragmented some protein strands, and made the collagen structure less stable. Enzymatic crosslinking produced a narrower range of stable aggregates. These results suggest that the desired properties of the end product should inform the selection of crosslinking technique.
Technical Abstract: Insoluble type I collagen fibrils are used in several biotechnological research applications including artificial organ scaffolding, skin grafts and cell immobilization beads for fluidized bed reactors. In these applications, collagen is usually strengthened against enzymatic degradation and physical stresses by the addition of cross-links. A suitable collagen source for these purposes appears to be bovine corium, a by-product of the leather industry. The present study on ball-milled bovine type I collagen examined the documented cross-linking capabilities of glutaraldehyde and dehydrothermal drying with the relatively new enzymatic cross-linking technique involving microbial transglutaminase. To assess the degree of cross-linking by each technique, free amine groups remaining after cross-linking, collagenase resistance and size of cross-linked complexes were determined. Glutaraldehyde cross-linking resulted in the least number of free amines, highest molecular weight aggregates and highest resistance to collagenase degradation. Dehydrothermal drying also produced high molecular weight aggregates, but partially hydrolyzed the protein, making the fibril more susceptible to collagenase resistance. Microbial transglutaminase treated collagen produced large molecular weight aggregates and was more resistant to collagenase degradation than control collagen. This new cross-linking technique warrants additional research attention.