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.