Normal tissue development requires that cells alter their mechanical behaviors in different microenvironments to carry out their diverse functions. During cell spreading, migration, invasion and mitosis, cells exhibit a high degree of deformability, exhibiting almost a fluid-like behavior, whereas within quiescent differentiated tissues, cells must behave like an elastic solid to maintain their structural integrity in the face of an applied mechanical stress. These responses are governed by material properties of the cytoskeleton (an intracellular network of various filamentous biopolymers) as well as by stress-induced changes in biochemistry that modify the structure of the cytoskeleton. Although the mechanical properties of cells govern their form and function, and when abnormal, lead to a wide range of diseases, biophysical and biochemical mechanisms by which cells control their deformability are largely unknown. During the past decade, a growing body of evidence has indicated that mechanical prestress of the cytoskeleton has a central role in cell deformability and rheology. These prestress results from the action of tensional forces generated by cytoskeletal molecular motors and carried by cytoskeletal tension-bearing filaments and resisted by both extracellular matrix adhesions and by internal compression-bearing filaments. This seminar offers a brief survey of experimental and theoretical studies that describe the role of cytoskeletal prestress in the mechanical behavior of cells.
Dr. Dimitrije Stamenovic is an Associate Professor in the Department of Biomedical Engineering at Boston University, where he has been a faculty member since 1987. He obtained his Ph.D. (1983) and M.S. (1980) degrees in mechanics from University of Minnesota, Minneapolis, and his Dipl. Ing. degree (1977) in mechanical engineering from University of Belgrade, Serbia. He served as a Research Fellow and a Research Associate in the Department of Environmental Health, Harvard School of Public Health from 1983 to 2000, where he is currently a Visiting Scientist. In 2002, Dr. Stamenovic was a Visiting Professor in the Faculty of Mathematics at University of Belgrade. He authored 70 articles in peer reviewed journals, 6 book chapters and 1 patent application. From 1999 to 2000, he served as a member of the Cell and Molecular Biology NASA Peer Review Panel. He is currently a member of the Editorial Board of The Open Applied Physics Journal and an Associate Editor of the ASME Journal of Biomechanical Engineering. Dr. Stamenovic's research interests have been in the areas of mechanics and rheology of living cells, respiratory mechanics, application of fractional calculus to tissue and cell rheology, biomechanics of cartilage, mechanics of liquid foams and foam-like materials, and theoretical and applied of elasticity.