Size and shape-based separation using deterministic lateral displacement microfludic systems

Continuous separation of particles of different sizes and shapes is important in both clinical diagnostics and industrial applications and a number of methods have been developed for such separations. In microfluidic systems, deterministic lateral displacement has proved its great potential in achieving the goal of high throughput and efficient separation. Although it was originally based on transporting the suspension in a convective flow, particles can be also driven with external force fields, thus force-driven DLD (f-DLD) devices were demonstrated. This thesis demonstrates the separation of suspended particles by shape and size using scaled-up macroscopic f-DLD devices, using gravity force and a centrifuge, respectively. In the first set of experiments and for the first time, we demonstrate the potential of gravity-driven DLD devices for the separation of particles of different shapes. Our results show that each type of particle moves in different directions within the array of obstacles in DLD systems, depending on the forcing direction. Interestingly, we show that the migration of the particles can be predicted by the diameter of the inscribed sphere, independent of shape. In the second set of experiments and also for the first time, we combined DLD devices with centrifugal force as the driving field. We show that spherical particles of different sizes are driven to different outlets. We show that at some specific angles this setup provides high separation resolution, but the resolution decreases as the concentration of particles increases.M.S.Includes bibliographical referencesby Mingliang JiangThis work was partially supported by the National Science Foundation Grant no. CBET-1339087