Geckos can stick to walls and zip across ceilings thanks to the adhesive properties of tiny nanoscale projections on their feet. By mimicking this nanotopography, an international team of scientists has developed a waterproof, biocompatible, biodegradable adhesive that could be used to seal wounds (Proc. Natl. Acad. Sci. USA 2008, 105, 2307). Jeffrey M. Karp, of Harvard Medical School, and Robert S. Langer, of MIT, spearheaded the effort inspired by the grabbing power of gecko feet. To create their adhesive, Karp and Langer's team casts a poly(glycerol sebacate acrylate) elastomer into a mold that's studded with tiny cavities. They then cure the material with UV light at room temperature for a few minutes. To enhance the sticking power of the resulting array of microscopic pillars (shown), the researchers coat the material with a thin layer of oxidized dextran containing aldehyde groups, which promote covalent cross-linking with tissue. Tests show the material sticks well to the abdominal tissue of living rats and causes only mild inflammation.