10 June 2015
New research has found that the surface structure of a Queensland gecko’s skin is so extraordinary it could have countless industrial, scientific and medical applications worldwide if replicated.
A team of scientists, led by Dr Greg Watson, now based at the University of the Sunshine Coast, and the University of Hong Kong’s Dr David Green, examined the skin of the box-patterned gecko of Western Queensland.
Their discovery of how the gecko’s skin expels water by making droplets clump together then self-launch like popcorn from the surface, received worldwide attention in April with media coverage including National Geographic and New Scientist and translations into many languages.
"My wife, scientific collaborator and co-author, Jolanta, was the first to notice the phenomenon on the gecko so she coined a new word to describe it – Geckovescence," said Dr Greg Watson.
"The skin has dome-shaped scales covered in very tiny spinules (spine-like hairs) which create this superhydrophobic surface and water droplets literally leap off under their own power. We are currently exploring this phenomena for diverse uses such as water collecting devices to self-propelled micro machines and rotors.
"By automatically keeping itself dry, we assume the gecko avoids potentially harmful microbes and fungi breeding on its skin. We’ve recently tested the surface with droplets of red wine, blood, soy sauce and other common liquids and it resists all of them."
The group’s latest research, published in the international journal of biomaterials science research Acta Biomaterialia, outlines other amazing properties of the skin structure and Dr Watson believes the development of a coating that replicates it has enormous potential for medical and industrial applications.
They found that not only does the gecko skin repel liquids, it self-cleans, resists dirt and pollen and kills bacteria on contact but provides a suitable surface for the growth of human stem cells.
"The gecko skin amazingly has all these features incorporated into a thin, wear-resistant and highly flexible sheet," Dr Watson said.
"We placed the bacteria that causes gingivitis on the gecko skin and found that most were killed quite quickly, which we think is caused by the tiny spinules deforming the bacteria. Though when we applied human stem cells – which are much larger than bacteria – to the surface, they grew very well."
"The development of water-repelling, self-cleaning, anti-bacterial and biocompatible coatings is of great interest from practical, commercial and scientific perspectives worldwide."
"Its uses could include medical and dental implants and other medical equipment such as catheters, syringes, contact lenses and wound-healing architectures. Then there could be self-cleaning indoor and outdoor surfaces, marine structures and membranes used in industrial applications, such as water filters."
Dr Jolanta Watson explained that the couple’s interest in science, including the work they have done on the nanostructure of gecko skin and insect wings, comes from an intense curiosity about how things work in nature.
"Ultimately, we’re interested in how organisms survive," she said. "From that we can learn a heck of a lot because they do survive and have survived for much longer than we have by developing finely tuned strategies to contend with an often hostile environment.
"So far we’ve only looked at the skin of one species of gecko and there are hundreds out there, so who knows what else we might discover?"
Drs Greg and Jolanta Watson previously worked at James Cook University and joined USC in January 2015 to teach chemistry and physics respectively.
Their previous and ongoing research collaborations have included examining the nanostructure and properties of insect wings, especially cicadas.
Some of the gecko skin research was carried out at JCU and the University of Queensland with two of the report’s contributing authors – Professor Lin Schwarzkopf (JCU) and Dr Bronwen Cribb (UQ).
— Jane Cameron