New Adhesive Mimics Geckos' Toe Pads

Geckos (Family Gekkonidae) belong to a group of small lizards that possess a remarkable ability to climb smooth, vertical surfaces with speed and ease. This impressive talent hinges on the geckos' specially adapted toe pads.

Each of the gecko's toe pads is covered with microscopic hair-like stalks known as setae. These tiny bristle-like structures are stiff and frayed at the ends. The setea have unique adhesive properties—they are not sticky or moist like more familiar adhesives (such as tape or glue) yet they attach strongly to a wide range of surfaces. Unlike tape or glue, gecko toe pads stick without marring the surface with adhesive, they are easy to remove, do not stick to one another, and do not collect dirt from the surfaces to which they stick. Setae are formed from stiff hydrophobic keratin that act as a bed of angled springs and adhere to surfaces via molecular forces known as van der Waals forces.

Scientists have now developed a 'next generation' of adhesives that are modeled after geckos' remarkable toes. These new adhesives attach with great strength and release with ease and for that reason are far better than conventional pressure-sensitive adhesives such as tapes and glues (which are either strong and difficult to remove or weak and easily removed).

The development of the new adhesive was possible thanks to a unique team of scientists that included biologists (Professor Keller Autumn from Lewis and Clark College and Robert Full from University of California, Berkely) and engineers (Ron Fearing and his colleages, also from University of California, Berkely).

Find out more:

• The Pitter Patter of Little Feet Climbing Straight Up a Wall (Eurekalert)
• Autumn K, Gravish N. 2008. Gecko adhesion: evolutionary nanotechnology. Philosophical Transactions of the Royal Society. 366: 1575-1590.
• Images of Geckos (AutumnLab Images)
• Autumn K. 2006. How Gecko Toes Stick. American Scientist. 94:124-132.
• Autumn K, et. al. 2006. Evidence for Van der Waals Adhesion in Gecko Setae. Proceedings of the National Academy of Sciences. 99(19)12252–12256.
• Smart Gecko Tape (UC Berkeley)

Photo (top) © K. Autumn / Lewis and Clark College. A gecko sits atop a glass surface in this image from the NIRT laboratory. Photo (bottom) © J. Lee and R.S. Fearing / UC Berkeley. A close-up of the new adhesive material developed to mimic the way gecko toe pads stick to surfaces.