Mechanical and Aerospace Engineering Colloquium

November 8, 2017
November 8, 2017
Speaker: Sean Sun, Ph.D.
                  Johns Hopkins University       
Title: Going With the Flow: Mechanics of Cell Motility and Metastasis
Location: Easton Hub Auditorium
                  Fiber Optics Building
Time:  3:30 p.m.
Abstract: Water plays a fundamental role in many aspects of cell dynamics. From first principle considerations as well as recent microfluidic experiments, it is now clear cell shape changes and cell movement can be driven by water as well as from the dynamics of the cytoskeleton. The water-driven mode of cell migration is mediated by osmotic pumping of ions (osmotic engine model) across the cell membrane, and is especially important in cancer metastasis. It is not clear what determines the relative contributions of actin and water to the observed cell movement. Here, we consider a 2-phase hydrodynamic model of cell movement, incorporating actin flow and water flow, frictional forces from cell adhesions, and movement of the cell membrane. When all of the mechanical forces are considered, we find that the frictional resistance experienced by the migrating cell can determine the relative contribution of actin and water to the observed cell speed. More generally, osmotic regulation is an important aspect of cell mechanical behavior, and determines slow deformation mechanics of tissue cells.  We find that there is a feedback control system that couples membrane tension to actomyosin contraction, which explains how cells respond to mechanical forces. Osmotic pumping is also responsible for water reabsorption in the kidney, can generate many kinds of slow movements observed in cells, including the constriction dynamics (cytokinesis) important during cell division.
Bio: Prof. Sean Sun joined Johns Hopkins University Mechanical Engineering and Biomedical Engineering as an assistant professor in 2003. He came to Johns Hopkins from UC Berkeley, where he received his Ph.D. and postdoctoral training. Since then, Prof. Sun’s research has focused on understanding mechanical phenomena in living cells, mathematically modeling the mechanistic basis of fundamental processes such as cell division, cell migration and cell force generation. He is also interested in mechanics of biological materials and stochastic processes in biology. He has published more than 85 articles at the interface between physics, mechanics, math and biology. He is the recipient of the Alexander von Humboldt Foundation Award and the NSF CAREER award. He is a fellow of the American Physical Society and American Institute for Medical and Biological Engineers. He also currently serves as the vice chair of mechanical engineering.
For additional information, please contact Professor Aaron Mazzeo at or 848-445-0504.