(221h) Capsule Dynamics in a Microfluidic Cross-Junction

In recent years, various studies have investigated the flow dynamics of elastic capsules in straight microfluidic channels such as cylindrical, square and rectangular channels, constrictions and expansions. These studies have provided a better understanding for capsules utilized in numerous engineering and biomedical applications including targeted drug delivery, cell sorting and characterization, and blood flow in vascular capillaries.

In the present work, we investigate computationally the transient dynamics of an elastic capsule flowing in a microfluidic cross-junction. Our investigation shows that the intersecting lateral flows at the cross-junction act like a constriction. Thus, the stronger hydrodynamic forces owning to the intersecting lateral flows cause a significant capsule deformation while the capsule obtains different transient shapes as its flows inside the microfluidic device. In addition, low-viscosity capsules form sharp tails as they exit the cross-junction. Our findings suggest that the tail formation of low-viscosity capsule may promote membrane breaking and thus drug release of pharmaceutical capsules in the microcirculation.