(195q) Sorting Red Blood Cells (RBCs) By Deformability in a Microfluidic Device

Sorting devices are widely used in biotechnology for diagnostics and to investigate the mechanical properties of cells under different conditions. For instance, these devices can be employed for measuring the deformability of the Red Blood Cells (RBCs) due to different diseases such as malaria. Similarly, the study of the blood rheological properties in strong confinement (such as arterioles and capillaries) is mostly determined by the behavior of the individual RBCs as well as influenced by their mutual interactions and with the walls.
Recently, numerical simulations of RBCs have attracted great attention as a viable mean to obtain detailed information about the rheological and mechanical properties of the blood and RBCs. Among different numerical methods, the Helfrich phase-field formulation has been extensively adopted for modelling biological cells and membranes. In the phase-field framework, the membrane dynamics is implicitly solved through the evolution of an order parameter, thus, the implementation is straightforward and can efficiently exploit large-scale parallel computing.

In this project, we study how to exploit flow deformation to sort RBCs by their membrane stiffness in a microfluidic device. An immersed boundary method is employed to model the complex geometry of the sorting device (a diverging channel with a semi-spherical obstacle). RBCs are represented by an indicator function based on the Helfirch phase-field formulation. The effect of different values of the membrane stiffness on the trajectory of RBCs passing through the device are studied. Our results suggest that the proposed algorithm can be useful to test for blood diseases which can be diagnosed by stiffened RBCs.