Droplet Dynamics in Constricted Return Bends of Microfluidic Channels

Microfluidic delivery systems have been employed to facilitate cell seeding procedures in drug development for personalized medicine for cancer patients. Despite of the high-throughput nature and potential impact on clinical outcomes of these systems, the efficiency in cell trapping remains a challenge in the operation. Droplet-based microfluidics became one of the solutions due to the large size of the cell-enclosing droplets and their interfacial properties. This study is focused on the motion of the cell-enclosing droplet in a constricted return bends that help to restrict the release of the cells while maintaining the high-throughput nature of the device. In this preliminary study, a three-dimensional boundary element method is used to predict droplet shape, deformation and migration velocity under the influence of various fluid properties and operational conditions. A variety of channel geometries have been explored as well. The resulting computational framework will be used to guide the design of a droplet-based microfluidic delivery system for cell seeding in 3D tumor spheroid arrays.