Using an Evaporating Meniscus to Trap Cells in a Microfluidic Chip: Design and Modeling

A microfluidic device based on Marangoni effect on a volatile meniscus is proposed for cell enrichment and collection. The device consists of a main channel in which cells are flowing with the mainstream, and an open-outlet channel which is connected with the main channel. A meniscus is sustained in the opening channel and keeps evaporating since the outlet is open to the atmosphere. Marangoni vortexes are generated near the meniscus due to the non-uniform evaporation on the meniscus. The vortexes influence the flow field and cell dynamics in the main channel, which can be used to trap the cells. A comprehensive numerical simulation is adopted in present work to reveal how the heat and mass transport going on in such a system. The evaporation and vapor diffusion at the liquid-air interface, and the vapor diffusion in air are considered. The convections due to the evaporation and Marangoni effect are simulated.