Tetanus-driven biohybrid multi-joint robots powered by muscle rings with enhanced contractile force

Biohybrid actuators utilizing muscle rings have been limited to twitching
movements and are unsuitable for sustained contractile force applications.
In this study, we developed muscle rings capable of generating high
contractile forces under tetanus stimulation. By enhancing the rigidity of
pillar-shaped supports and increasing myoblast density through reduced
extracellular matrix, we promote the formation of dense, well-aligned
muscle fiber bundles. The optimized muscle rings exhibit significantly
higher contractile forces compared to traditional methods. Integrating
these muscle rings with C-shaped anchors efficiently converts contractile
force into bending motion. We demonstrate the application of these muscle
rings in gripper and slither-type biohybrid robots, achieving large
deformation and undulatory movement. This work advances biohybrid robotics
by enabling sophisticated movements requiring continuous and powerful
muscle contractions.