Spiny worm solves skin graft problem

A parasitic worm that latches onto the intestines of fish by inflating its head has led to a remarkable invention for keeping skin grafts in place, even when the surface of the wound is wet. Reporting in the journal Nature Communications on Tuesday, US researchers devised a patch studded with tiny cone-shaped needles as a replacement for surgical staples, a potential source of tissue damage and infection. The needles are made of a stiff core made of plastic and a tip that is rigid when dry but swells up on contact with water in surface tissue. Within 10 minutes, the tips are plumped up and secure the patch firmly on the skin, clamping grafts on burns and other injuries. "The unique design allows the needles to stick to soft tissues with minimal damage," said Jeffrey Karp, a biomedical engineer at Brigham and Women's Hospital, an affiliate of Harvard Medical School in New England. "Moreover, when it comes time to remove the adhesive, as opposed to staples, there is less trauma inflicted to the tissue, blood and nerves, as well as a reduced risk of infection." Inspiration for the patch came from Pomphorhynchus laevis, a spiny worm which penetrates the intestinal wall of sea fish and then plumps up its elongated cactus-like head so that it cannot be dislodged. The microneedles provide not just good anchorage, say the researchers. They also offer potential for channelling antibiotics and anti-inflammatory drugs into wounds at minute doses.