Computational Model of Cellular Adhesion in Bulk Flow

Charles Eggleton, Department of Mechanical Engineering, UMBC, Kostas Konstantopoulos, Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Vijay Gupta, Department of Mechanical Engineering, UMBC, Alex Szatmary, Department of Mechanical Engineering, UMBC, Ihab Sraj, Department of Mechanical Engineering, UMBC

Understanding, manipulating and controlling cellular adhesion processes is crucial to developing strategies among others, to target drug delivery via the circulatory system, grow self-assembling tissue structures in bioreactors, and miniaturize biosensors for the detection of environmental bacteria. Cellular adhesion involves nano-scale molecular interactions that occur between the cell membranes, while the contact distance, area, and time are determined by the imposed meso-scale flow and the bulk properties of the cell and the suspending fluid. Key issues in our knowledge of cell-cell adhesion under hydrodynamic shear flow conditions remain unresolved. Currently, receptor-ligand binding efficiency is inferred from cell-cell adhesion events interpreted in terms of hard sphere collisions which grossly underestimate the area of contact. Therefore a computational model based on the immersed boundary method 1 is being developed by the applicants to simulate cell-substrate and cell-cell interactions that accounts for both the molecular interactions and the response of the cell membrane to the bulk flow. The proposed construction and development of the numerical tools will be guided and validated by measurements of receptor-mediated leukocyte-Staphylococcus Aureus bacterial cell interactions under shear conditions, critical to the immune response.