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Fluid Dynamics Seminar

Monday, December 1, 2008, 4:00 PM
Cullimore Lecture Hall, Room 611
New Jersey Institute of Technology

From Molecular Dynamics for Proteins to Immersed Method for Fluid-Solid Systems - A Hierarchical Multi-Scale and Multi-Physics Model of Soft Biological Materials

X. Sheldon Wang

Department of Mathematical Sciences, New Jersey Institute of Technology

Abstract

The sickle cell anemia is the very first disease which can be pinpointed to the genetic cause at the DNA level. Hemoglobin in its quarterly molecular structure is very much like a bead. The red blood cell has many such beads within the cell cytoskeleton. The cause of the sickle cell disease is a simple switch of the DNA base pair from A to T, with this switch the codon will be changed from GAG to GTG. The normal hemoglobin at this particular location is slightly hydrophilic, thus tends to form a protective layer with the surrounding water molecules and are separated from each other. As a consequence, the normal red blood cell membrane is flexible and fluidic. Due to the sickle cell mutation, the hydrophilic spot becomes slightly hydrophobic and during the deoxygenated state, it tends to loose the protective layer of water molecules and consequently form a chain of hemoglobin bead. Moreover, such chains will continue to form bundles and eventually yield a very stiff and sticky material property for sickle cells. In the end, these sickle cells tend to block the capillary vessels and cause the sickle cell anemia. In this talk, we will use this red blood cell system (sickle or normal) to illustrate a hierarchical multi-scale and multi-physics modeling procedure combining molecular dynamics modeling of protein-protein interactions with immersed boundary/continuum methods for moving adhesive particles and soft continua.