Nanobots Getting Tangled Up? The Octopus May Have an Answer

In research that may one day find application in keeping nanobots from sticking to each other or tying themselves in knots, a study published in Current Biology details a Hebrew University of Jerusalem research team's efforts to understand how octopuses avoid getting tangled up in their own long, flexible, suction cup-lined arms.

Such research matters in the medical device space, because nanobots could be a medtech game-changer in coming years. (For example, Topol as chief academic officer at San Diego-based Scripps Health has been working with Axel Scherer, PhD, of Caltech on tiny blood stream nano sensor chips that might sense the precursor of a heart attack.) It also might help if there were easier ways to prevent surgical robots from getting their arms tangled up.

In "Self-Recognition Mechanism between Skin and Suckers Prevents Octopus Arms from Interfering with Each Other," co-first authors Nir Nesher and Guy Levy conducted experiments to discover how octopuses manage the no-tangling feat even though their brains are unaware of what their arms are doing.

It turns out, the researchers say, that a chemical produced by octopus skin temporarily prevents their suckers from sucking.

"We were surprised that nobody before us had noticed this very robust and easy-to-detect phenomena," says Levy, who carried out the research with Nesher. "We were entirely surprised by the brilliant and simple solution of the octopus to this potentially very complicated problem."

Writing for EurekAlert.org, Mary Beth O'Leary reports that Binyamin Hochner and his colleagues had been working with octopuses for many years, focusing especially on their flexible arms and body motor control. They say there is a very good reason that octopuses don't know where their arms are exactly, in the same way that people or other animals do.

"Our motor control system is based on a rather fixed representation of the motor and sensory systems in the brain in a format of maps that have body part coordinates," Hochner explains.

That works for us because our rigid skeletons limit the number of possibilities. "It is hard to envisage similar mechanisms to function in the octopus brain because its very long and flexible arms have an infinite number of degrees of freedom," Hochner continues. "Therefore, using such maps would have been tremendously difficult for the octopus, and maybe even impossible."

"The results so far show, and for the first time, that the skin of the octopus prevents octopus arms from attaching to each other or to themselves in a reflexive manner," the researchers wrote.

O'Leary says that this self-avoidance strategy might even find its way into bioinspired robot design.

"Soft robots have advantages [in] that they can reshape their body," Nesher says. "This is especially advantageous in unfamiliar environments with many obstacles that can be bypassed only by flexible manipulators, such as the internal human body environment."

In fact, the researchers are sharing their findings with European Commission project STIFF-FLOP, aimed at developing a flexible surgical manipulator in the shape of an octopus arm. "We hope and believe that this mechanism will find expression in such new classes of robots and their control systems," Hochner says.

Stephen Levy is a contributor to Qmed and MPMN.