Safer, More Sensitive Biohybrid Robots Could Be Created Using 3D-Printed "Soft Ceramic" Nerves

Researchers from the Soft Robotics Laboratory at ETH Zurich, the Empa Swiss Federal Laboratories for Material Science and Technology, and the University of Tokyo have developed a way to boost the sensitivity of future biohybrid robots — with ceramic-enhanced soft sensors combined with artificial muscles.

"Today's robotic systems are big, clunky and very strong. They can be dangerous for humans," says Frank Clemens, Empa research group leader and materials scientist, of the team's work. "If you accidentally touch another person, you automatically pull away. We want to give robots the same reflex."

"We work with so-called highly filled systems," Clemens continues. "We take a matrix made of a thermoplastic and fill it with as many ceramic particles as possible without compromising the elasticity of the matrix."

These "soft ceramics" can be used as "nerves" within equally-flexible components through 3D printing, demonstrated using prototypes for measuring pressure or temperature in a prosthetic hand — capable of using the ceramic sensors to track the flexion of its digits and the temperature of a touched surface, with a sensitivity the team says would be of use in both robotics and for human prostheses.

The team's latest work combines these ceramic sensors with artificial muscles to develop a biohybrid robot, using the "nerves" to track the contraction or extension state of each muscle.

"We expect our system to help improve the contractile ability of bioactuators by enabling the integration of sensors throughout the tissue differentiation and maturation process," the researchers conclude. "Our concept to sensorize bioactuators will enable biohybrid robots to overcome the challenge of full operative integration."

The team's work is to be published in the journal Advanced Intelligent Systems, with an early-access copy available in the Wiley Online Library under open-access terms.

Main article image courtesy of Empa.