Direct numerical simulation of micro-scale interaction between ice and biological cells

摘要

The freezing of biological material, such as cells and tissue, during cryopreservation involves the interaction of ice in the extracellular medium with living cells. This cell-ice interaction critically determines the success of the cryopreservation protocol, as measured by cell survival and viability after the freeze-thaw process. This paper presents numerical simulations of the response of a cell to freezing. The phase change of the aqueous salt solution outside the cell is computed using a sharp-interface technique. The cell is modeled as a salt solution enclosed by a semi-permeable membrane. We compute the concentration and temperature fields around a single cell in the presence of extracellular ice formation. Parametric variations in the factors affecting the cell-ice interaction are performed to describe the physics of thermo-solutal transport of the interaction. Cell water loss is quantified. The external ice front is computed for both stable and unstable (cellular/dendritic) growth modes. The results show that water egress from the cell is dependent on several controlling parameters in complex ways.