High-Fidelity Simulation of Cancer Cell Adhesion and Flow with Coarse Grain Modelling: A Numerical and Experimental Approach

A coupled CFD-DEM framework was developed to investigate red blood cell (RBC) transport and cellular adhesion in constricted microchannels, with a primary objective of reducing computational cost while preserving physiological accuracy. Initially, numerical softening factors were implemented to allow greater particle overlap and expedite computations, with an optimal value of 0.03 selected. Adhesion forces between RBCs and the channel wall were incorporated, with a minimum effective distance of 0.4 µm found to be computationally feasible. However, RBC–RBC adhesion led to artificial clustering and was therefore omitted. Coarse-graining methods were applied up to a factor of 2 to further reduce simulation time, with a value of 1.8 chosen based on consistent cell-free layer (CFL) thickness and drag force characteristics. To compensate for the increased drag in coarse-grained models, rolling resistance (Type C) with a coefficient of 0.8 was used, reducing deviations to within 10%. The validated model was then extended to simulate the detachment of adherent MCF-7 breast cancer cells under physiological flow. Experimental validation showed increasing cell retention with seeding time, and simulations reproduced this trend with <5% deviation. The resulting Detachment Force Ratio (DFR) at 30 min indicates near-equivalence between adhesion and hydrodynamic forces, establishing the model’s robustness for cell-substrate interaction studies in microfluidics.