Biohybrid tensegrity actuator driven by selective contractions of multiple skeletal muscle tissues

Abstract

Biohybrid robots are robots composed of both biological and artificial materials that can exhibit the unique characteristics commonly found in living organisms. Skeletal muscle tissues can be utilized as their actuators due to their flexibility and ON/OFF controllability, but previous muscle-driven robots have been limited to one-degree-of-freedom (DOF) or planar motions due to their design. To overcome this limitation, we propose a biohybrid actuator with a tensegrity structure that enables multiple muscle tissues to be arranged in a 3D configuration with balanced tension. By using muscle tissues as tension members of tensegrity structure, the contraction of muscle tissues can cause the movement of the actuator in multiple degrees of freedom. We demonstrate the fabrication of the biohybrid tensegrity actuator by attaching three cultured skeletal muscle tissue made from C2C12 cells and fibrin-based hydrogel to an actuator skeleton using a snap-fit mechanism. When we applied an electric field of more than 4 V mm-1 to the skeletal muscle tissue, the fabricated actuator had a structure to tilt in multiple directions through the selective displacement of about 0.5 mm in a specific direction caused by the contractions of muscle tissue, resulting in 3D multi-DOF tilting motion. We also show that the actuator possesses superior characteristics of tensegrity structure such as stability and robustness by assessing the response of the actuator to external force. This biohybrid tensegrity actuator provides a useful platform for the development of muscle-driven biohybrid robots with complex and flexible movements.

Pillar electrodes embedded in the skeletal muscle tissue for selective stimulation of biohybrid actuators with increased contractile distance

“…Greater selective resolution and contractile distance enable the biohybrid robots to perform more complex and lifelike movements [5]. Among biological tissues, skeletal muscle tissue is a popular choice for biohybrid actuators due to its flexibility, ON-OFF controllability, and high output efficiency [6][7][8]. Previous studies have enabled biohybrid robots to achieve biomimetic movements such as swimming [4], gripping [9], pumping [10], and rotating [11].…”