They’re no suckers: why octopuses don’t get their tentacles in a twist

The octopus has a built-in non-stick mechanism that may have medical uses, according to researchers. Plus: When liquid meets solid

Thu, May 22, 2014, 01:00

Ever wondered why an octopus doesn’t get its limbs all stuck together in a tangle? The answer could lie in molecules produced by the animal’s skin that appear to prevent the suckers from sticking to it, according to a new study of Octopus vulgaris.

The local “don’t stick here” signal, described in the journal Current Biology, is a simple solution to a complicated problem, explains researcher Dr Guy Levy from the Hebrew University of Jerusalem.

“Instead of having to calculate where and when its arms touch each other in order to prevent non-voluntary manipulations between them . . . this mechanism prevents any such manipulations without any calculations,” he says.

The researchers are thinking about how this could be translated into robotic systems – they are part of the European Commission- funded project Stiff-Flop to build a “soft manipulator” in the shape of an octopus arm for medical uses.

“This soft manipulator can be programmed to avoid manipulating obstacles on the way to the target in the same way that octopus arms are programmed to avoid manipulating each other,” says Levy. “For example, if this manipulator will be inserted into a human intestine . . . [to] reach a target, it can be programmed to avoid grabbing and manipulating the internal walls of the intestine on the way, using chemical recognition of these walls.”

Research simmers away at solid-liquid interface A biology teacher who swapped the classroom for the university lab has developed a new way to look closely at what goes on at the interface between solids and liquids.

The solid-liquid interface, or nanoscale boundary where a solid and liquid meet, is an important site for many processes such as energy storage, corrosion and even the biochemistry of our bodies.

However, it can be difficult to get information about both the structure and chemistry of the interface together, explains Liam Collins.

A PhD student with the Nanoscale Function Group at University College Dublin, he is first author on a paper published this week in Nature Communications that describes an approach to overcome that technical hurdle. Called electrochemical force microscopy, it measures not only the structural landscape of the solid-liquid interface, but also how chemical ions behave over time.

“[It] is based on the atomic force microscope and can be implemented without any modifications to the existing microscope, making it applicable across a broad range of fields in research,” says Collins.

He initially studied science education and did his teacher training in schools in Galway and Mayo before moving into university-based research at UCD’s Conway Institute.

It was a long process to develop the approach, he adds, and it involved collaborators in the US and Ukraine.

But Collins hopes that the data it generates will offer new levels of insight.

“We know very little about the electrochemical processes that happen at solid-liquid interfaces but now we have a new way to probe these processes in situ at the nanoscale,” he says.

“And being better able to understand what is going on at this level could ultimately lead to more effective energy storage devices, new biomaterials for use in biological systems and, hopefully, even new insights into disease.”