Single Cell Deformation and Detachment Models of Shear Assay Measurements

Abstract

This paper presents concepts for the modeling of cell deformation and cell detachment from biocompatible biomedical materials. A combination of fluid mechanics and fracture mechanics concepts is used to model the detachment of cells under shear assay conditions. The analytical and computational models are validated by shear assay experiments in which human-osteo-sarcoma (HOS) cell are detached from surfaces that are relevant to bio-micro-electro-mechanical systems (BioMEMS), bio-microelectronics and orthopaedic/dental implants. The experiments revealed that cell detachment occurs from patches in which of α/β integrins are separated from the extracellular matrix that is left on the substrate. The stress/strain distribution and energy release rates associated with the observed detachments are also computed using elastic cell deformation, fluid/structure interactions and linear fracture mechanics (LEFM) model. The simulations reveal show that cancer cells generally experience higher levels of deformation than normal cells. The simulations also revealed that the cell-extracellular matrix interface was prone to cell detachment (interfacial failure), as observed in the shear assay experiments. The critical energy release rates for normal cell detachment were also found to be greater than those required for the detachment of cancer cells. The implications of the results are discussed for the design of biomedical implants and their interfaces.