My mistake! From the PM article: "Also, by blending in conductive wire or wrapping the muscle with a light-absorbing coating, the researchers can control the m

My mistake! From the PM article: "Also, by blending in conductive wire or wrapping the muscle with a light-absorbing coating, the researchers can control the muscles' movements with electricity and light instead of direct heat." So these are heat-driven actuators (and potentially electricity or light driven). Very cool! Thanks for the clarification. (Also, this isn't at all evident from the Science abstract. I will read full paper tomorrow when I can pierce the paywall.)