Interphase Interaction Effects on Lateral Migration of Cells in Microchannels

Precise control of cell lateral positions in microchannels is critical for high-accuracy cell isolation, with such positioning primarily governed by lateral migration. Among the various factors influencing lateral migration, interphase forces play a key but underexplored role. In this study, a simulation model was developed to resolve the evolution of interphase interaction during cell–cell collisions. Using this model, we systematically analyze cell migration under the combined influence of lateral lift forces and interphase force. The results show that under low Reynolds number (Re) conditions, lateral lift forces dominate, and cells gradually reach equilibrium positions through repeated collision and separation. As Re increases, however, collisions occur with greater relative velocity, generating stronger interphase forces that drive rapid separation and induce transient but pronounced shifts in lateral cell position, typically persisting for only a few milliseconds, with peak displacements of about 25% of the equilibrium position. Experimental validation of the simulation results is achieved through microcapillary flow tests with blood cells and particles, supporting the simulation model's predictive accuracy. Notably, we observe the formation of transient secondary rings under high Re conditions, which are attributed to interphase interactions. This study delivers mechanistic insights into intercellular dynamics in confined microflows and establishes a rigorous modeling framework for the design of high-throughput, high-purity cell isolation systems.