1. Washington University, Department of Biomedical Engineering, St. Louis, Missouri 63130, United States
2. Albert Einstein College of Medicine, Gruss-Lipper Biophotonics Center, Department of Anatomy and Structural Biology, Bronx, New York 10461, United States
3. Washington University School of Medicine, Department of Obstetrics and Gynecology, St. Louis, Missouri 63130, United States