A team of engineers at Penn State has harnessed the properties of the skin of nature’s most fascinating cephalopods, such as octopuses, squids, and cuttlefish to create stretchy and smart artificial skin. The artificial skin mimics the elasticity and neurological functions of cephalopod skin, and it could be used for a wide range of applications like neurorobotics, skin prosthetics, artificial organs, and more.
The research was published in the Proceedings of the National Academy of Sciences. The team was led by Cunjiang Yu, Dorothy Quiggle Career Development Associate Professor of Engineering Science and Mechanics and Biomedical Engineering.
Recreating Cephalopod Skin
Cephalopod skin is a soft organ that can endure complex deformations like expanding, contracting, bending, and twisting. It also has cognitive sense-and-respond functions that enable the skin to sense light, react, and camouflage to its weather.
These types of artificial skins are not entirely new, and there have been previous versions with similar physical and cognitive capabilities. But, Yu says none has simultaneously exhibited both qualities, which is necessary for advanced, artificially intelligent bioelectric skin devices.
“Although several artificial camouflage skin devices have been recently developed, they lack critical noncentralized neuromorphic processing and cognition capabilities, and materials with such capabilities lack robust mechanical properties,” Yu said. “Our recently developed soft synaptic devices have achieved brain-inspired computing and artificial nervous systems that are sensitive to touch and light that retain these neuromorphic functions when biaxially stretched.”
Achieving Smartness and Stretchability
The researchers set out to achieve both smartness and stretchability at the same time, and they did this by building synaptic transistors made entirely from elastomeric materials. The rubbery semiconductors, which send critical messages back and forth, operate in a similar way to neural connections. They are not impacted by the physical changes in the system’s structure.
Yu says that the key to creating this type of skin device was to use elastomeric rubbery materials for every component, which resulted in the device successfully exhibiting and maintaining neurological synaptic behaviors. It was able to exhibit these behaviors, including image sensing and memorization, even when it was stretched, twisted, and poked.
“With the recent surge of smart skin devices, implementing neuromorphic functions into these devices opens the door for a future direction toward more powerful biomimetics,” Yu said. “This methodology for implementing cognitive functions into smart skin devices could be extrapolated into many other areas, including neuromorphic computing wearables, artificial organs, soft neurorobotics and skin prosthetics for next-generation intelligent systems.”
The research also included co-authors Hyunseok Shim, Seonmin Jang and Shubham Patel, Penn State Department of Engineering Science and Mechanics; Anish Thukral and Bin Kan, University of Houston Department of Mechanical Engineering; Seongsik Jeong, Hyeson Jo and Hai-Jin Kim, Gyeongsang National University School of Mechanical and Aerospace Engineering; Guodan Wei, Tsinghua-Berkeley Shenzhen Institute; and Wei Lan, Lanzhou University School of Physical Science and Technology.