Numerical Analysis of a Trapezoidal Microchannel for Hydrodynamic Detachment of Cells

Hydrodynamic shear force along the bottom microchannel wall has been utilized in cell adhesion studies to detach cells in microfluidic channels. Due to the small dimensions of microfluidic channels, the shear stress produced in a conventional microchannel is dependent mainly on the fluid velocity and channel height. The wall shear force magnitude increases as the channel height is reduced. However, a reduced channel height decreases the sample volume to be contained in the fluidic channel and also increases the pressure drop significantly which may fail the fluidic device. In this study, a novel microchannel with a trapezoidal structure was investigated using computational fluid dynamics simulations. The key fluidic properties, including wall shear stress, sample volume, and pressure drop of the trapezoidal microchannel are compared with those of a conventional straight channel with a reduced channel height. We found the trapezoidal structure produces a wall shear stress of 5 Pa in the region of interest similar to that of the straight channel with a small channel height (50 μm) while having less than 30 percent pressure drop. Additionally, the pressure drop can be reduced by modifying the geometry of the trapezoidal channel to minimize pressure loss.