Glucose and oxygen power artificial muscle for implants and self-sufficient robots

The exciting and terrifying prospect of self-sufficient robots has come a step closer, after researchers created an artificial muscle powered by glucose and oxygen.

Devices based on the technology could be implanted into people’s bodies as artificial muscles – or help create autonomous robots powered by the biomolecules in their surroundings.

The human-like polymer actuator was created by a team at Linköping University in Sweden. The researchers sandwiched a thin membrane layer between two layers of polypyrrole, an electroactive polymer in which they integrated naturally-occurring enzymes that convert chemical energy into electrical energy.

The team placed the actuator in a glucose solution, and said it was “just amazing” to see it move as ions flooded from one sheet of polypyrrole to the other. As one side expanded and the other shrank, it bent in one direction like a muscle.

Batteries usually power artificial muscles, but they are heavy and require regular charging. The researchers said glucose was a useful alternative, but the technology could be developed to work with other substances.

“Glucose is available in all organs of the body, and it's a useful substance to start with. But it is possible to switch to other enzymes, which would enable the actuator to be used in, for example, autonomous microrobots for environmental monitoring in lakes. The advances we present here make it possible to power actuators with energy from substances in their natural surroundings,” said project leader Edwin Jager, senior lecturer in sensor and actuator systems.

The muscle’s motion is reportedly reversible, but the researchers hope to control the biochemical reactions in the enzymes to make it reversible over “many” cycles. They also want to test the concept using other actuators, and to apply the technology in microrobots.

The research was published in Advanced Materials.