Kit Yan Chan, Mechanical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, Julia M. Ross, UMBC, 1000 Hilltop Circle, Baltimore, MD 21250, and Charles Eggleton, Mechanical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle Baltimore, Engineering 205, Baltimore, MD 21250.
A better understanding of the cellular detachment process is essential in combating numerous life-threatening conditions, such as microbial infections, thrombolysis, biofilm breakup, cancers metastasis, etc. This study investigates numerically the cellular detachment process of a modeled Staphylococcus aureus bacterial cell from a collagen-coated surface in a shear flow. The cell is modeled as an elastic capsule with receptor sites located on the cell membrane surface. The coupled flow field and the cell shape are solved using the Immersed Boundary Method; with the elastic membrane forces obtained using a standard Finite Element technique. The receptor-ligand bonds are described by the Hookean spring model. The imposed shear rates are within a range of physiologic shear rates observed in the vasculature, and a range of receptor densities representing the different bacterial strains and growth phases are used in the simulations. The influences of the strength of the shear field, the receptor density on the cell surface, and the cell deformability on the cellular contact area and subsequent detachment (if any) are presented. In vivo studies have demonstrated that unattached bacterial cells have a lower probability to cause infection than an attached cell; hence, favorable conditions promoting cellular detachment are identified and discussed in this presentation.