MEDFORD, MASSACHUSETTS — A new wearable bioreactor could be the first step towards limb regeneration.

Researchers led by Tufts University scientists have developed a wearable bioreactor that uses progesterone to induce tissue regeneration. The device was tested on adult aquatic African clawed frogs, a species already capable of partial limb regeneration.

The 3-D printed bioreactor is made from silicon and filled with hydrogel. The gel is a mix of silk proteins that aid healing and progesterone, a hormone that prompts tissue repair.

According to their study, published in the journal Cell Reports, frogs in the experiment had one of their hind legs amputated approximately at the center of the femur. The wounds of the frogs were either treated with the bioreactor, protected by the device without progesterone or left untreated.

All groups had their devices removed after 24 hours. After nine and a half months, the the group that had worn the bioreactors with progesterone grew a paddle-like structure with bones, nerves and blood vessels. Those which did not grew a cartilaginous spike-like structure. The use of progesterone proved to alter the limbs at an functional and anatomical level.

Scientists hope this finding takes us a step closer to technology that could aid regeneration of human amputated limbs.