David T. Scadden received his M.D. degree from Case Western Reserve School of Medicine. Following his internship and residency at the Brigham and Women's Hospital in Boston, he completed a Clinical Fellowship in Medicine and in Hematology/Oncology at the Harvard Medical School, the Brigham and Women's Hospital, and the Dana-Farber Cancer Institute. Subsequently, he was a Research Fellow at these institutions working with James M. Cunningham and later at the New England Medical Center working with Robert S. Schwartz and John M. Coffin. He joined the faculty at Harvard University as an Instructor and is presently Professor of Medicine at the Harvard Medical School and Director of the Center of Regenerative Medicine at Massachusetts General Hospital. Dr. Scadden's research interests are focused on the bone marrow and stem cell biology. He is particularly interested in the regulation of entry and exit from the cell cycle, as this has important implications for expansion of stem cells and gene transduction. He is also interested in the regulation of stem cell localization to and within specific microenvironments and the interactions of stem cells with elements of the microenvironmental niche. These studies are critically important in understanding how stem cells develop and how they may function in regenerative processes in many organs. His work has been published in many outstanding journals including *Nature*, *Nature Medicine*, *Science*, *Nature Biotechnology*, *Proceedings of the National Academy of Science USA*, the *Journal of Clinical Investigation*, and the* Journal of Immunology and Blood*. He has received many honors, including elected membership in the American Society for Clinical Investigation and the Association of American Physicians. He serves on the editorial boards for many journals including *Blood, Stem Cells, and Experimental Hematology*, and he is an Associate Editor for *Blood*.

Mehmet Toner is a member of the Senior Scientific Staff at the Shriners Hospital for Children. He is a co-founder of the Center for Engineering in Medicine, and founder of the NIH BioMicroElectroMechanical Systems (BioMEMS) Resource Center at the Mass General. In addition, he is Director of the Biomedical Engineering Research and Education Program for physicians at Mass General.

Gordana Vunjak-Novakovic received her Ph.D in chemical engineering from the University of Belgrade, Serbia in 1980. She is currently a professor in the Department of Biomedical Engineering at Columbia University. She also serves as the director of the Laboratory for Stem Cell and Tissue Engineering at Columbia. Professor Vunjak-Novakovich has also taught at Tufts University and the University of Belgrade, as well as work as a research Scientist at MIT.