Sneaky Color-Changing Octopus Inspires Deception Tech

An octopus that can change the size and color of patterns on its skin has inspired a deception technology platform for use in a variety of fields, including the military, medicine, robotics, and sustainable energy.

This article was written by Brian Bell-UC Irvine and originally published by Futurity.

With a split-second muscle contraction, the greater blue-ringed octopus can change the size and color of the namesake patterns on its skin for purposes of deception, camouflage, and signaling.

The new devices will benefit from dynamically adjustable fluorescent and spectroscopic properties, ease of manufacturing, and potential for scaling to areas large enough to cover vehicles, billboards, and even buildings, the inventors say.

A study of bio-inspired creation appears in Nature Communications.

Hapalochlaena lunulata is a species of octopus native to the Western Pacific Ocean and Indian Ocean. It uses a neurotoxin venom to stun its prey and can ward off predators with a flash of its blue rings. These iridescent circles on a brown background on the creature’s skin are what drew the researchers’ attention.

“We are fascinated by the mechanisms underpinning the blue-ringed octopus’ ability to rapidly switch its skin markings between hidden and exposed states,” says senior coauthor Alon Gorodetsky, professor of chemical and biomolecular engineering at the University of California, Irvine.

“For this project, we worked to mimic the octopus’ natural abilities with devices from unique materials we synthesized in our laboratory, and the result is an octopus-inspired deception and signaling system that is straightforward to fabricate, functions for a long time when operated continuously, and can even repair itself when damaged.”

The architecture of the innovation calls for a thin film consisting of wrinkled blue rings surrounding brown circles—much like those on the octopus—sandwiched between a topmost transparent proton-conducting electrode and an underlying acrylic membrane, with another identical electrode underneath.

Further technical creativity by the researchers occurs at the molecular level as they explored the use of acenes, which are organic compounds made up of linearly fused benzene rings. Designer nonacene-like molecules (with nine linearly fused rings) used by the team help give the platform some of its outstanding capabilities, according to Gorodetsky.

“For our devices, we conceptualized and designed a nonacene-like molecule with a unique architecture,” says co-lead author Preeta Pratakshya, who recently received her PhD from UCI’s chemistry department. “Acenes are organic hydrocarbon molecules with a host of advantageous characteristics, including ease of synthesis, tunable electronic characteristics, and controllable optical properties.

“Our nonacene-like molecules are exceptional among acenes because they can survive years of storage in air and over a day of continuous irradiation with bright light in air. No other expanded acene displays this combined long-term stability under such harsh conditions.”

The type of molecules used to fabricate the colored blue ring layer are what endow the devices with their most favorable features, including adjustable spectroscopic properties, the facilitation of straightforward benchtop manufacturing, and ambient-atmosphere stability under illumination, Gorodetsky says.

“Our coauthor Sahar Sharifzadeh, a Boston University professor of electrical and computer engineering, demonstrated that the stimuli-responsive properties of the molecules can be computationally predicted, which opens paths for the in silico design of other camouflage technologies.”

In their laboratory tests, the team found that the bioinspired devices could change their visible appearance over 500 times with little or no degradation, and they also could autonomously self-repair without user intervention.

The invention was demonstrated to possess a desirable combination of capabilities in the ultraviolet, visible light, and near-infrared parts of the electromagnetic spectrum, according to Gorodetsky. This would enable the devices to disguise other objects from detection or to clandestinely signal observers.

“The photophysical robustness and general processability of our nonacene-like molecule—and presumably its variants—opens opportunities for future investigation of these compounds within the context of traditional optoelectronic systems such as light-emitting diodes and solar cells,” Gorodetsky says.

Additional coauthors are from UC Irvine and Boston University.

The Office of Naval Research, the Defense Advanced Research Projects Agency, and the National Science Foundation supported the work.

Source: UC Irvine