Polymer gel prevents skin grafts from shrinking

When skin is irreparably damaged by burns, skin taken from other areas of the patient’s body – or created by tissue engineering – is grafted onto the burned area. Although grafts often heal successfully, the skin shrinks significantly in nearly a third of patients. The process is painful and disabling, and particularly common in children.

Karima Bertal and colleagues at the University of Sheffield have now developed an enzyme-inhibiting drug which can halve this contraction, and loaded it into a biocompatible polymer gel to smear onto the graft. Bertal presented the group’s preliminary results at the Royal Society of Chemistry’s Biomaterials conference in Manchester, UK, earlier this month.

Sheila MacNeil, the scientist who leads the research, told Chemistry World that currently the only accepted treatment for graft contraction is to have the patient wear pressure garments – extremely tight clothing that pushes down on the dermis to prevent it forming bumps of contracted tissue.

Her research team found that an enzyme called lysyl oxidase is involved in causing the graft contraction, as it ties together collagen fibres in the deep dermal layer of the skin. Then they identified a compound that inhibits the enzyme, called 3-aminopropionitrile, and combined it with a biocompatible polymer gel invented by chemist Steve Armes, also at Sheffield.

Tests of the drug on human skin samples were successful: ‘The control grafts contract to about 60 per cent of their original size, but [when the drug is applied] they only contract down to 80 per cent,’ Bertal told Chemistry World.

The gel also works as they hoped: ‘Our polymer gel is well tolerated by the skin and releases the drug in a controlled manner over about 48 hours,’ she said.

The team has now started testing the drug-gel combination itself on human skin samples, and early results looks promising, said MacNeil. ‘If they’re successful, we would like to move into the clinic,’ she said.