The heart circulates blood as if it were wringing a towel; the bottom twists in a counterclockwise direction while the top twists clockwise. Engineers have recreated this motion in an artificial muscle.
In the model heart, tube-like pneumatic artificial muscles (PAMs) mimic the heart’s striated muscle fibers.
To achieve the heart’s 3D motion, the team embedded their soft modified PAMs—made of silicone elastomer in a braided mesh—in a matrix also made of soft silicone elastomer. The top images show the team’s heart prototype as it is subjected to various pressures. The middle images show a computer model of the mesh only as it deforms at corresponding pressures, and the third row is a computer model showing how the heart changes its motion in response to the different pressure regimes. U indicates displacement.