Researchers at the Tokyo University have developed a robot that utilizes real muscles.

Led by Professor Shoji Takeuchi, the research team attached laboratory-cultured muscle cells to bones made of plastic, and ran precise electric currents through the setup to induce contractions.

The result was essentially a"human" arm with antagonistic and agonistic muscles - opposing pairs of muscles that relax or contract. The arm could maintain sufficiently rigid postures and thus lift objects, the first hybrid robot of its kind.

"It's still in the very early stages, but I think it's a big first step," said Shoji. The research team hopes to push its development even further into the production of prosthetic hands. Having durable yet flexible artificial limbs might be great and all, but having natural-looking ones made of real muscle is just also desirable.

Challenges include the replication of the extremely intricate muscle composition of human hands, the development of a reliable power source to generate electric currents, and of course dealing with muscle degradation over time.