RIVERSIDE, Calif., Sept. 29 (UPI) -- Only 60 percent of geckos have adhesive toe pads. Of the 40 percent that do not, many belong to the genus Gonatodes, a group of dwarf geckos.
But new analysis suggests one Gonatodes species is on its way to developing adhesion. Researchers at the University of California, Riverside say Gonatodes humeralis offers a "snapshot" of evolution.
"The gecko adhesive apparatus, one of the most spectacular innovations displayed by vertebrates, has been intensively studied for the last 16 years and is of considerable interest to nanotechnologists and biomimeticists," Timothy Higham, a gecko expert and associate professor of biology at UCR, said in a news release. "But almost nothing is known about the origin of this adhesive capability."
While studying Gonatodes geckos, Higham and his research team were surprised to find microscopic hairs, called setae, beneath the toes of Gonatodes humeralis. The hairs produce attractive forces, called van der Waals forces, allowing the gecko to adhere to smooth surfaces.
In the forests of Trinidad and French Guiana, the hairy toes of Gonatodes humeralis allow it to adhere to leaves and bamboo shoots, safe from predators -- places its closest relatives are unable to venture.
Researchers say the species' adhesive toes -- all thanks to the sprouting of a few tiny hairs -- offer it a huge competitive advantage.
"Until now, we had not seen a gecko showing the beginnings of the adhesive system," Higham said. "In all the innovations seen in the animal kingdom, we rarely get to see their beginnings."
Higham says the new findings -- detailed in the Biological Journal of the Linnean Society -- offer further proof of the falsities of "intelligent design" theories.
"Complexity does not start with complexity. Small modifications can, however, lead to complexity," Higham said. "Key innovations can come about in small incremental steps and lead to feedback processes that result in the more complex renditions of such systems. Our research offers more experimental evidence to show this is true."
LEIDEN, Netherlands, Sept. 28 (UPI) -- Graphene is extremely sensitive to its surroundings, making it an ideal source material for biosensors. However, graphene must be mounted on a stable substrate so its structural integrity is maintained.
For applications outside the human body, graphene is typically mounted on hard inorganic materials. But to transport graphene through the human body, scientists need a substrate derived from organic materials.
Recently, researchers at Leiden University found what they were looking for. Scientists in the Netherlands succeeded in placing graphene on top of a stable fatty lipid monolayer -- a first.
Lipids are fat molecules. They form a protective double layer around cell membranes. Researchers believe if they can sandwich a layer of graphene between two layers of lipid molecules, the 2D material will be ready for a journey into the human body.
"[It is] a method that is already used with cancer medicines," Leiden chemist Grégory Schneider said in a news release -- describing the initial success. "We made a single layer of lipids in the lab and transferred graphene on top: a first step towards mimicking the cell membrane."
In their experiments -- detailed in the journal Nanoscale -- Schneider and his researcher partner Lia Lima found the lipid layer enhanced the conductivity of graphene. Measuring the electric conduction of graphene while inside the body is key to its potential as a future biosensor. Electric currents can offer clues as to the presence of acids and proteins.
Now, researchers just need to find a way to build the lipid-graphene sandwich.