||Measurement and Analysis of Lymphocyte Deformation in Microchannel Contraction Flows Using a Compound Drop Model
Tatsumi, K. ,
Haizumi, K. ,
Sugimoto, K.Nakabe, K.
Flow, Turbulence and Combustion
260 , 2016-01 , Springer Netherlands
First online: 05 August 2015
To understand the physical properties of lymphocytes and to develop a numerical model that can predict their motion and deformation in flows, a three-dimensional numerical simulation of lymphocytes flowing through the contraction region of a microchannel was performed using a compound drop model. The present model considers shear-thinning effects on the cytoplasm and the nucleus by modeling a second droplet inside the primary cell. The time-dependent characteristics of the deformation index (DI) of the lymphocyte, and the effects of the flow rate and the nucleus position on the DI are discussed and compared with the measurement. The results demonstrated that the conventional drop model, in which Newtonian fluid properties are applied to the cytoplasm, cannot correctly predict the deformation of the cell in the contraction region, where the nonlinear effects become important, whereas the compound drop model was consistent with experimental measurements of lymphocyte deformation. The size and position of the nucleus were found to influence the shape of the lymphocyte as measured by a change in the deformation rate of the leading and trailing sides of the lymphocyte. Further, a simplified model of lymphocyte deformation in the steady elongational flow was employed to determine the apparent viscosity, including the shear-thinning effects, of the lymphocyte.