An adaptive, Cartesian, front-tracking method for the motion, deformation and adhesion of circulating cells

Cells in circulatory systems adhere through a competition between molecular interactions and colloidal repulsion, while the cells arbitrarily deform in the presence of external fluid forces. The complex coupling of the forces involved, the disparate length scales at which they act, and uncertainties in the mechanics of cell deformation have complicated the study of cell adhesion. To address these difficulties, a multi-fluid, front-tracking method with staggered, adaptively refined meshes has been developed. As a tool to study cell mechanics, the program allows the incorporation and testing of different mechanical models of the cell without significant changes in the setup. As a tool to study cell adhesion, the method models the coupling of the relevant forces resolving the disparate length scales involved. The method was validated by simulating various test cases, and the results were found to agree well with analytical and other numerical solutions. The capabilities of the method are demonstrated with the simulation of a common cell-mechanics experiment (a micropipet assay) and a common physiological situation for cell adhesion (the adhesion of two cells under shear flow). (C) 1998 Academic Press.