A particle-based model for healthy and malaria-infected red blood cells
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A particle-based model for healthy and malaria-infected red blood cells

James J. Feng

Department of Chemical and Biological Engineering and

Department of Mathematics

University of British Columbia

Vancouver, BC V6T 1Z3, Canada

http://www.math.ubc.ca/~jfeng

In this talk, I will describe a smoothed particle hydrodynamics method for simulating the motion and deformation of red blood cells. After validating the model and numerical method using the dynamics of healthy red cells in shear and channel flows, we focus on the loss of red cell deformability as a result of malaria infection. The current understanding ascribes the loss of RBC deformability to a 10-fold increase in membrane stiffness caused by extra cross-linking in the spectrin network. Local measurements by micropipette aspiration, however, have reported only an increase of about 3-fold in the shear modulus. We believe the discrepancy stems from the rigid parasite particles inside infected cells, and have carried out 3D numerical simulations of RBC stretching tests by optical tweezers to demonstrate this mechanism.

Our results show that the presence of a sizeable parasite greatly reduces the ability of RBCs to deform under stretching. Thus, the previous interpretation of RBC-deformation data in terms of membrane stiffness alone is flawed. With the solid inclusion, the apparently contradictory data can be reconciled, and the observed loss of deformability can be predicted quantitatively using the local membrane elasticity measured by micropipettes.

Bio: James J. Feng received his B.S. (1985) and M.S. (1988) degrees from Peking University in Beijing, and his Ph.D. (1995) from the University of Minnesota, all in Fluid Mechanics. After a postdoctoral stint at the University of California, Santa Barbara, he was appointed an associate professor at the Levich Institute for Physicochemical Hydrodynamics in New York City, where he carried out research in non-Newtonian fluid dynamics and polymer rheology and taught in the Mechanical Engineering department of the City College of New York. In 2000, he received the NSF Career Award for work on multicomponent polymer flows. In 2004, he moved to the University of British Columbia in Vancouver, Canada, as a Canada Research Chair in Complex Fluids and Interfaces, with a joint appointment in Chemical and Biological Engineering and Mathematics. His current research covers multiphase and interfacial fluid dynamics, cell and tissue mechanics and morphogenesis.