Anyway, we got them back. My tech and I started culturing them, and there was one experiment I wanted to do and it was an experiment we'd done with mouse embryonic stem cells. We tried to find an alternative to what they call feeder cells because you had to have these fibroblasts, otherwise they didn't grow. And I had made a cell line from a teratocarcinoma, mouse teratocarcinoma, which was endoderm-like, and it had turned out that the mouse embryonic stem cells formed heart cells on it. So, I thought, I wonder what would happen if we put the human embryonic stem cells on those endoderm cells, mouse endoderm cells. And lo and behold, 14th of February, 2001, we had beating heart cells. Valentine's Day. My technician comes running along the corridor completely hysterical, says "We've got beating heart cells!" It was wonderful. And that's actually determined what we've done since.

Dr. Christine Mummery is a professor of developmental biology at Leiden University and head of the Department of Anatomy and Embryology at the Leiden University Medical Center. Her work specializes in stem cell biology, cardiovascular development, and developmental biology.

In 1974, she received her Bachelor of Science degree in physics, electronics, and mathematics from the University of Nottingham, UK and in 1978 received her PhD in biophysics from the University of London, UK for her research at King’s College London. She received a post-doctoral fellowship at the Royal Society, UK from 1978 to 1980, and in 1981 continued her fellowship at the Hubrecht Institute working with carcinoma cells. In 1985, she was appointed to a tenured staff scientist working on developmental biology and differentiation.

In 2011, Dr. Mummery founded the iPSC&OoC Hotel facility in the Leiden University Medical Center. From 2009 to 20019, she was the head of the department of Anatomy and Embryology at Leiden University and guest professor at the University of Twente from 2015 to 2023. She was president of the ISSCR from 2020 to 2021 and is the founding editor of its journal, Stem Cell Reports.

Dr. Mummery has received several awards for her work in developmental biology, including the 2014 Hugo van de Poelgeest Prize for Animal Alternatives, the 2014 Hans Biomendaal Medal for innovative interdisciplinary research, being an elected member of the Academia Europaea in 2015 and Royal Netherlands Academy of Arts and Sciences in 2010, the 2021 Fondation Lefoulon Delalande-Institut de France prize for cardiovascular physiology, and the ISSCR Public Service Award in 2023.