Analysis of lymphocytes deformation in microchannel flows using compound drop model

Abstract

To understand the physical properties of the lymphocytes and develop a numerical model that can predict the motion and deformation of lymphocytes in flows, three-dimensional numerical simulation of the lymphocytes flowing through the contraction region of the microchannel was carried out employing the compound drop model in this study. The present model considers the shear-thinning effect of the cytoplasm, and includes the nucleus by applying another drop inside the cell. The results were compared with the experimental ones measured by recording the lymphocyte deformation using the high-speed camera. The time- dependent characteristics of the deformation degree DI of the lymphocyte, and the effects of the flow rate and the nucleus position on the DI were discussed. The results showed that the conventional drop model applying the Newtonian fluid properties to the cytoplasm cannot predict the deformation in the contraction region correctly where the nonlinear effects become important. The present model, on the other hand, showed a good agreement with the measured one. Further, the nucleus showed a significant effect on the shape of the lymphocyte. The rigid nucleus supressed the cell deformation and a slight deviation of its position affected the deformation rate of the leading and trailing sides markedly.