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March 2017 Volume 12 No 3

Optogenetic skeletal muscle cells embedded in a natural hydrogel matrix self-assemble to form mature contractile myotubes. When the fibers are coupled to a 3D-printed soft robotic skeleton, optically stimulated contraction of this muscle tissue can produce force and generate directional locomotion. These muscle bioactuators set the stage for the next generation of bio-hybrid machines, termed bio-bots. Tissue stained by Vincent Chan and imaged by Vincent Chan and Ritu Raman. Image from Cvetkovic, C. et al. Proc. Natl. Acad. Sci. USA 111, 10125–10130 (2014).