Healing wounds with leather, meat waste

Various tissues available as inedible by-products in abattoirs can be successfully used for biomedical applications

Utility: Collagen scraps generated during leather-making can be used in regenerative medicine, says Chellappa Muralidharan (left).

Protein extracted from discarded animal tissues can now be put to better use — wound healing and human tissue engineering. This waste-to-wealth feat was demonstrated by researchers from the Chennai-based CSIR-Central Leather Research Institute (CSIR-CLRI).

In the meat industry, tonnes of animal tissues that are rich in collagen (protein) go waste. The researchers have found that various collagenous tissues available as inedible by-products in abattoirs can be successfully used for the production of collagen-based products for biomedical applications. “Collagen has been reported to play a major role in healing of tissues, but their low mechanical strength and fast biodegration has restricted its use. We tried to overcome these limitations by incorporating the collagen with another biopolymer, chitosan, obtained from shells of crustaceans,” says Dr. Chellan Rose, the corresponding author of the paper published in RSC Advances, who has now retired from CLRI.

The collagen-chitosan scaffold was cross-linked with an amino-acid L-arginine to impart stability. It also helps avoid side-effects caused by toxic chemical cross linkers.

Wound healing studies

The freshly prepared 3D scaffolds were first tested

in vitro on mouse fibroblasts. The cell population increased significantly in 48 hours suggesting that they were able to anchor to the 3D scaffold and proliferate. For in vivo studies, a small cutaneous wound was created on a lab rat and treated with the new scaffold and covered using micropore tape. Complete wound closure was seen at the end of 14 days with no scar formation.

Computer simulation studies further examined the possible interactions of the collagen with arginine and chitosan. Molecular docking revealed that the compounds bind well and the arginine helped the stability of collagen-chitosan interaction.

Structure of the scaffold

Scanning electron microscopy studies showed that the scaffold had a uniform, interconnected porous structure with pore size of about 50-400 micrometre. The decreased pore size but high porosity of the material helped in water uptake by the scaffold and facilitated cell migration, adherence and proliferation.

“This hybrid scaffold is specifically developed for highly exudating wounds to absorb the fluid and to keep the wound dry for faster healing,” explains Mr. S. Udhayakumar, first author of the paper.

“Even the collagen scraps generated during the different operations of leather making can be used as biomaterial in the field of regenerative medicine. The scaffolds will cost less than the existing collagen-based healing products. Human clinical trials are in progress and the results are encouraging,” says Dr. C. Muralidharan at the Leather Processing Division, CLRI and one of the authors of the paper.