Physics Colloquium, "The unique biomechanical properties of the cell: Insights from computational modeling," by Dr. Roger D. Kamm, Departments of Biological and Mechanical Engineering; Massachusetts Institute of Technology

Science / Technology - Colloquium

Monday, April 23, 2012
4:00 PM-5:00 PM

Olin Hall

Cytoskeletal rheology is of central importance in the transmission and sensing of force by the cell, and in dynamic processes such as migration, mitosis, and contraction against a compliant external matrix. Computational models have been used for years to gain insight into the mechanics of the cytoskeleton. Such models have the potential to help interpret experimental measurements and test hypotheses regarding the underlying physics that determines cell rheological properties. In our present Brownian dynamics model, filaments polymerize from individual monomers, in the presence or absence of crosslinking agents or molecular motors, creating a network with realistic 3D morphology. Once formed, the networks can be subjected to shear deformations over a range of frequencies, simulating the measurements made either in living cells or reconstituted actin gels. Measuring stresses responding to the applied deformation of a specified magnitude provides a means for calculating the frequency-dependent shear moduli  the storage modulus, G and the loss modulus, G. Modeling has progressed through several stages: a) a cross-linked network with permanent cross-links, b) a dynamic network in which the crosslinks can both rupture (according to Bells equation) and rebind, and fold and unfold, and c) a network that contains both dynamic cross-links and processive motors capable of generating internal prestress. Results will be presented for each level of model complexity, addressing linear and nonlinear behavior, plastic deformations, and the molecular origins of each.

Refreshments will be served in Olin Hall 118 at 3:30 P.M.

Cost: Free

Suggested Audiences: College

Phone: 508-831-5258

Last Modified: March 29, 2012 at 10:44 AM

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