By mimicking a technique used by an intestinal parasite of fish, researchers have developed a flexible patch studded with microneedles that holds skin grafts in place more strongly than surgical staples do. After burrowing into the walls of a fish's intestines, the spiny-headed worm Pomphorhynchus laevis inflates its proboscis to better embed itself in the soft tissue. In the new patch (sample shown in main image), the stiff polystyrene core of the 700-micrometer-tall needles (inset) penetrates the tissue; then a thin hydrogel coating on the tip of each needle—a coating based on the material in disposable diapers that expands when it gets wet—swells to help anchor the patch in place. In tests using skin grafts, adhesion strength of the patch was more than three times higher than surgical staples , the researchers report online today in Nature Communications. Because the patch doesn't depend on chemical adhesives for its gripping power, there's less chance for patients to have an allergic reaction. And because the microneedles are about one-quarter the length of typical surgical staples, the patches cause less tissue damage when they're removed, the researchers contend. Besides holding grafts in place, the patch could be used to hold the sides of a wound or an incision together—even, in theory, ones inside the body if a slowly dissolving version of the patch can be developed. Moreover, the researchers say, the hydrogel coating holds promise as a way to deliver proteins, drugs, or other therapeutic substances to patients.
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