1 Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic Surgery, Department of Surgery, Stanford University School of Medicine, 257 Campus Drive, Stanford, CA, 94305-5148, USA.
2 Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA.
3 Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic Surgery, Department of Surgery, Stanford University School of Medicine, 257 Campus Drive, Stanford, CA, 94305-5148, USA. dwan@stanford.edu.