A team of scientists designed a device that can induce partial hindlimb regeneration in adult aquatic African clawed frogs (Xenopus laevis) by “kick-starting” tissue repair at the amputation site. Their findings, appearing November 6 in the journal Cell Reports, introduce a new model for testing “electroceuticals,” or cell-stimulating therapies.
“At best, adult frogs normally grow back only a featureless, thin, cartilaginous spike,” says senior author Michael Levin, developmental biologist at the Allen Discovery Center at Tufts University. “Our procedure induced a regenerative response they normally never have, which resulted in bigger, more structured appendages. The bioreactor device triggered very complex downstream outcomes that bioengineers cannot yet micromanage directly.”
The scientists 3D printed the bioreactor out of silicon and filled it with hydrogel — a sticky glob of polymers. They laced the hydrogel with hydrating silk proteins that promote healing and regeneration, then added progesterone. Progesterone is best known for its role in preparing the uterus for pregnancy, but the hormone has also been shown to promote nerve, blood vessel, and bone tissue repair.