Original publicity materials: https://www.pennmedicine.org/news/news-releases/2017/january...

Paper: https://dx.doi.org/10.1126/science.aai8792

This is somewhat different from earlier lines of research into scarless healing in mammals, such as the work based on the biochemistry of MRL mice ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3806350/ ).