An elevenfold gain came out of one design decision
Robots that use living muscle tissue as an actuator have been around for a while; what is new is modelling the muscle and the scaffold that carries it as one system and optimizing them together, instead of working on the muscle physiology alone. The team at ETH Zurich built that unified system in a soft-body simulation framework, ran an evolutionary algorithm and targeted parameter sweeps to maximize range of motion, then fabricated the resulting form by integrating skeletal muscle tissue with a microgrooved hydrogel scaffold. Range of motion grew up to elevenfold over previous designs of similar muscle volume.[1]
That number could have stayed a parlour trick, and it does not, because the same actuator powered robots that jump, swim, walk and grip, and the system scaled into multi-unit assemblies. In the paper's supplementary footage the motions appear at fields between 3.3 and 5 volts per centimetre and pacing of 1 to 3 beats per second. Beyond a single narrow demonstration, what is on the table is a repertoire of motions coming out of one design pipeline; the continuous interface transmits force efficiently from muscle to scaffold, which is what allows the large, rapid deformations.[1]
What a living machine can carry
The real gain here sits in the design loop rather than in the living tissue itself: the form is searched for in simulation and then grown together with the tissue. There is a more modest explanation standing against that reading — the geometry of the microgrooved hydrogel scaffold may on its own account for most of the gain, independently of the co-optimization loop. Telling the two apart means knowing where the elevenfold comes from; and the evidence in the paper shows the gain was measured against previous designs of similar muscle volume, while offering no measurement of the muscle itself improving.[1]
It is still worth stopping on: skeletal muscle grown on a hydrogel scaffold jumps, swims and grips under an electric field. For now these machines work in a controlled setting, to a pace supplied from outside, at centimetre scale. There is a concrete way to tell when that threshold has been crossed: a peer-reviewed study reporting a bioactuator from this same pipeline doing work without externally applied electrical pacing and outside the controlled bath. Until such a study appears, what we hold is a possibility; and for you, reading the news tonight, the question now is who makes these machines, and what for.[1]