An Autonomous Chemically Fueled Artificial Protein Muscle

Complex multimaterial networks of the human body, for example, muscles, enable dynamic autonomous movements. Bioinspired mimicry of muscular systems is of great interest in soft robotics and biomedicine. Currently a broad range of synthetic macromolecules and natural or modified biomacromolecules imitate muscular systems, but no protein muscles with mechanoactive protein components are realized. Biomimetic bio-based muscle systems allow to combine the potential of nature's high-performance proteins, for example, silk, resilin, elastin, or titin, with novel adaptive and functional properties and sustainable biotechnological production. While biological protein motors and muscles are powered by the hydrolysis of adenosine triphosphate, no synthetic bio-based muscles are described, operating autonomously using chemical energy to exert directional movements. Herein, an artificial protein muscle is introduced, exerting rhythmic autonomous movements via nonequilibrium states driven by chemically fueled pH oscillation reactions. Key to the design are recombinantly produced human matrix proteins selectively reengineered to respond to different stimuli. The results also show how directional movements can be independently triggered by changes in pH and temperature including a selective on-switch and a combination of nonequilibrium states enabling learning and oblivion-like material effects. This paves the road for the next generation of autonomous materials in pharmacy, soft robotics and living matter.

Automated summary

Complex multimaterial networks in the human body enable dynamic autonomous movements, which has sparked great interest in bioinspired mimicry of muscular systems in soft robotics and biomedicine. This article introduces an artificial protein muscle that exhibits rhythmic autonomous movements through chemically fueled pH oscillation reactions driven by nonequilibrium states.