Long, colorful strands of engineered muscle fiber have been stained to observe growth after implantation into a mouse. Biomedical engineers have grown living skeletal muscle that looks a lot like the real thing. It contracts powerfully and rapidly, integrates into mice quickly, and for the first time, demonstrates the ability to heal itself both inside the laboratory and inside an animal. The study conducted at Duke University tested the bioengineered muscle by literally watching it through a window on the back of living mouse. The novel technique allowed for real-time monitoring of the muscle’s integration and maturation inside a living, walking animal.

This series of images shows the destruction and subsequent recovery of engineered muscle fibers that had been exposed to a toxin found in snake venom. This marks the first time engineered muscle has been shown to repair itself after implantation into a living animal.

This series of images shows the progress of veins slowly growing into implanted engineered muscle fibers.

Read: Self-Healing Engineered Muscle Grown in the Laboratory