“How did you go broke?” a character asks in Hemingway’s The Sun Also Rises. “Two ways: gradually, and then suddenly.” The same can be said of the cartilage in our knees and elbows. For most of our lives, this thin layer of tissue absorbs forces of up to ten times our body weight — every step, every jump, every decade — without failing. And then, sometimes, it does.
How does cartilage do so much for so long, and why does it eventually give way? In this lecture, I will show that the answer lies in a beautiful piece of physics: cartilage is a network of microscopic fibers living right on the edge of a phase transition between soft and stiff. Small changes — a little less collagen, a little less swelling pressure — can produce enormous changes in how the tissue responds to load. The same principle that protects your joints for eighty years can, once crossed, lead to sudden failure. And the same principle, we are beginning to learn, can guide us in designing a new generation of resilient, lifelike materials.
About Moumita Das
Moumita Das is a Professor of Physics at the Rochester Institute of Technology, where she leads a research group at the interface of soft matter physics and biology. Her group uses theory and computation to understand how living materials — from the cartilage in our joints to the scaffolds of our cells — get their remarkable mechanical properties, and how the same principles can inspire a new generation of smart, resilient materials.
She earned her PhD from the Indian Institute of Science in Bangalore and held postdoctoral fellowships at Harvard, UCLA, and the Vrije Universiteit Amsterdam before joining RIT in 2012. She is a Fellow of the American Physical Society, and her work has been recognized with a Cottrell Scholar Award, a Scialog Fellowship, and RIT's Norman A. Miles Award for Academic Excellence in Teaching. Her research is supported by the National Science Foundation and the National Institutes of Health.
Beyond research, she is active in science policy and in efforts to make physics a more welcoming field, and she co-organizes an international virtual seminar series in biological physics.