威尼斯人

Title:　Simulating the mechanics of malaria-infected red blood cells

 

Speaker: James J. Feng

Department of Mathematics and

Department of Chemical and Biological Engineering

University of British Columbia

Vancouver, BC V6T 1Z3, Canada

 

 

Place: 数学楼二楼学术报告厅

 

We use computer simulations to investigate the progressive loss of deformability of red blood cells (RBCs) due to malaria infection. The prevailing understanding ascribes the RBC rigidification 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 membrane  modulus. We surmise that the discrepancy stems from the rigid parasite  particles inside infected cells, and have simulated two types of  experiments that have been used to probe the RBC's deformability:  stretching by optical tweezers and transit through microfluidic channels. Results show that with parasite growth and division through  the ring, trophozoite and schizont stages of malaria, the parasite exerts an increasing mechanical effect on restricting RBC deformation.  With the solid inclusion, we can rationalize the apparently anomalous  data from stretching experiments, and predict the amount of cell  stretching quantitatively using the local membrane elasticity measured by micropipettes. In microfluidic channels, we show how the transit time increases with RBC rigidification, and predict eventual blockage that  has been recorded in prior experiments.

 

Bio-sketch: 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 (UBC) in Vancouver, Canada, as a Canada Research Chair in Complex Fluids and Interfaces, with a joint appointment in Chemical and Biological  Engineering and Mathematics. He received the CFI (Canada Foundation for Innovation) Leaders Opportunity Award in 2008, and the NSERC (Natural  Sci. & Eng. Res. Council) Discovery Accelerator Award in 2009. He was also a UBC Killam Faculty Research Fellow during 2010-2011, and a  Visiting Fellow at the Newton Institute, Cambridge University, in 2013. He was elected fellow of the American Physical Society in 2013 and

appointed a Distinguished Scholar in Residence at the Peter Wall  Institute for Advanced Studies at UBC for 2014-2015. His current  research covers multiphase and interfacial fluid dynamics, cell and  tissue mechanics and morphogenesis.