An Improved Coarse-Grained Model to Accurately Predict Red Blood Cell Morphology and Deformability

Accurate modelling of red blood cells (RBCs) has greater potential over experiments, as it can be more robust and significantly cheaper than equivalent experimental procedures to investigate the mechanical properties, rheology and dynamics of RBCs. The recent advances in numerical modelling techniques for RBC studies are reviewed in this study, and in particular, the discrete models for a triangulated surface to represent the in-plane stretching energy and out-of-plane bending energy of the RBC membrane are discussed. In addition, an improved RBC membrane model is presented based on coarse-grained (CG) technique that accurately and efficiently predicts the morphology and deformability of a RBC. The CG-RBC membrane model predicts the minimum energy configuration of the RBC from the competition between the in-plane stretching energy of the cytoskeleton and the out-of-plane bending energy of the lipid-bilayer under the given reference states of the cell surface area and volume. A quantitative evaluation of several cellular measurements including length, thickness and shape factor, is presented between the CG-RBC membrane model and three-dimensional (3D) confocal microscopy imaging generated RBC shapes at equivalent reference states. The CG-RBC membrane model predicts agreeable deformation characteristics of a healthy RBC with the analogous experimental observations corresponding to optical tweezers stretching deformations. The numerical approach presented here forms the foundation for investigations into RBC morphology and deformability under diverse shape-transforming scenarios, in vitro RBC storage, microvascular circulation and flow through microfluidic devices