New microneedle skin graft patch outperforms surgical staples
By Ben Coxworth
April 17, 2013
You’ve gotta love those Pomphorhynchus laevis worms. Although the parasites may feed on fish by attaching themselves to the inside of the host animal’s intestines, they’ve also provided the inspiration for a new system of keeping skin grafts secured over wound sites.
The worms are able to secure themselves within the intestines by penetrating the intestinal wall with their spiny head, and then plumping that head up to keep it wedged in place. A team led by Dr. Jeffrey Karp from Harvard-affiliated Brigham and Women’s Hospital sought to recreate that same sort of attachment mechanism for skin grafts.
What resulted is a patch with an array of cone-shaped microneedles on its underside. Each of those needles has a rigid polystyrene core, covered with a tip made from a plastic that remains rigid when dry, but that swells when wet.
The idea is that a skin graft will first be laid in place over a burn, infection, incision or other wound site, and then the patch gets placed over top of it. The microneedles easily penetrate all the way through the graft, and into the underlying tissue. As the tips come into contact with body fluids they expand, thus interlocking with the surrounding tissue, and keeping both the patch and the graft securely in place. The swelling process can be reversed when it’s time to take the patch off.
Currently, grafts are held in place using sutures or surgical staples. The microneedle patches, however, reportedly produce over three times the adhesion strength. They also offer a more uniformly-distributed source of adhesion, they cause less trauma to body tissue, and present less of a risk of infection.
The patches could also conceivably be used to close incisions in internal surgical procedures, and to deliver medication into the surface of wounds.
This isn’t the first animal-inspired microneedle patch to be developed at scientists at Brigham and Women’s Hospital. In another study that included colleagues from MIT, they created a patch with needles inspired by porcupine quills, that could find use as a surgical adhesive.
A paper on the worm-inspired patch was published yesterday in the journal Nature Communications.
Source: Brigham and Women’s Hospital