Gecko Skin Is Surprisingly Un-Sticky

Geckos may have the ability to stick to walls, but it seems that not much sticks to them.

Geckos may have the ability to stick to walls, but it seems that not much sticks to them.

The skin of the box-patterned gecko (Lucasium sp.) is able to prevent the adhesion of everything from household liquids to dirt and bacteria, according to new research. The skin also exhibited self-cleaning properties.

This discovery may have important implications for the design of medical implants, self-cleaning hospital surfaces and even water filters.

"Gecko skin is very thin -- only a few microns deep -- and they live in a hostile environment where bacteria can flourish, so we wondered what other protective measures the skin might confer," says Dr Greg Watson from the University of the Sunshine Coast, one of the leaders of the international team who undertook the research.

They found that the skin of the gecko consists of dome-shaped scales that are made up of super-tiny spinules -- or hairs -- ranging in size from several hundred nanometres to several microns in length.

When the researchers tested the skin's response to a range of contaminants such as pollen and dust, they found that they just didn't stick.

"The skin's topography provides a super-hydrophobic, anti-wetting layer that allows droplets as small as those found in fog to roll and even jump off the peaks and through the valleys in the skin, taking dirt, pollen and other contaminants with them," Watson explains.

Their study is published in Acta Biomaterialia.

Box-patterned geckos are found in the semi-arid Mingela Ranges in Western Queensland.

"The geckos are small, which means they have a high surface area to volume ratio, that is they have a lot of skin relative to their body mass," Watson says.

Watson and team also found that gecko skin shares many of the same structural properties as cicada wings, which are known to repel water and contaminants.

When the researchers placed Porphyromonas gingivalis, the bacteria that causes gingivtus and periodontal disease, on the gecko skin they found that most were killed within less than a day, without any application of chemicals.

Watson says that while they are not certain of what killed the bacteria, it is possible that they were impaled on the skin's spiny surface.

"However when human stem cells (from tooth pulp) were applied to the skin surface, they grew happily."

He says that stem cells are much larger than bacteria, which may explain why they were able to withstand the impact of the spines.

Watson says that the development of water-repelling, self-cleaning, anti-bacterial and biocompatible coatings in terrestrial and aquatic environments is of great interest worldwide.

"The gecko skin's anti-bacterial action may represent a new line of enquiry into such interactions where selective bacterial activity is required," he says.

"It may help deal with the growing problem of antibiotic resistance by providing an alternative way of minimising exposure to bacterial contamination in medical and dental implants, contact lenses, syringes and catheters and on hospital and other surfaces.

"It also has potential applications in marine structures and in membranes in water filters, which will allow water to be cleaned physically, rather than by using chemicals."

June 7, 2011 --

More than 600 new species of animals and plants have been discovered in Madagascar in the past decade, according to a new report by the World Wildlife Fund. The discoveries include 385 plants, 42 invertebrates, 17 fish, 69 amphibians, 61 reptiles and 41 mammals. Although all of these species are new to science, many are believed to be endangered due to threats ranging from deforestation to illegal wildlife trading. Explore some of the most fascinating animals discovered in past decade in this slide show. We begin with this curious-looking chameleon. With a red splash on color on its head and blue spots all over its body, this "glam-rock" chameleon (Furcifer timoni) received its name because of the vibrant colors that adorn its skin. Found in the isolated rainforests of the Montagne d’Ambre in northern Madagascar, it is one of 11 species of chameleon discovered in Madagascar since 1999.

Biologists may have shown up a little too soon when they discovered this new species of frog. In this photo, a male frog (Boophis lilianae) holds onto a female during mating in their native habitat of Ranomafana National Park in Madagascar. Since 1999, nearly 70 amphibian species have been discovered in Madagascar.

Discovered in 2000, this mouse lemur (Microcebus berthae) sure wasn't an easy find. Fully grown, the lemur reaches on average 3.6 inches in length, making it the world's smallest known primate. Found in the Kirindy Mitea National Park in Western Madagascar, this little guy is one of 28 lemurs discovered in the past decade.

This bright yellow frog may appear to have come down with the measles, but this is actually the species' natural coloring. Boophis bottae, a native of the eastern rainforest belt of Madagascar, is already under threat due to habitat loss from a variety of sources, including agriculture, logging, expanding human populations and more.

With a predominantly white body mixed with splashes of black and gray spots throughout, this chameleon (Calumma tarzan) is named after Tarzan. Although partly credited to the fact that the species was discovered near a small village called Tarzanville, the name actually comes from researchers who gave the chameleon its moniker with the hopes that it would raise awareness of the threat to this animal and its habitat.

This earth-toned frog (Gephyromantis tschenki) was first spotted in 2001 in Madagascar's nature preserves.

While this cork bark leaf-tailed gecko may be easy enough to spot against the black background, this animal blends in perfectly with its surroundings in the eastern coastal rainforest of Madagascar. Like many of the animals in this slide show, Uroplatus pietschmanni is threatened by habitat loss and the pet trade.