(387b) A Membraneless Microfluidic Architecture for Continuous Separation of Particles and Cells

We have developed a microfluidic filtration architecture based on an embedded weir-like barrier separating two lanes with unequal depths. The barrier is oriented parallel to the flow direction and extends along the entire centerline length of the microchannel, making it possible to process large volumes with no clogging. Here we report coordinated experiments and computational simulations aimed at quantifying the interplay between longitudinal and lateral pressure distributions within the microchannel that govern the achievable separation efficiency in this system. These new studies reveal that the effect of unequal microchannel depths on each side of the central barrier can be coupled with a transverse centrifugal Dean flow introduced along a curved flow path segment, enabling greatly enhanced separation and enrichment to be achieved across a broad range of flow rates. A 3D computational fluid dynamics model was developed to capture the features of the secondary flow field, while a coupled discrete element modeling algorithm tracked trajectories of individual species under the influence of all relevant hydrodynamic forces and torques. This analysis enables a universal correlation to be established linking all device design parameters (cross-sectional area profile, length of microchannel, flow rate), permitting rational design for efficient size-based filtration of desired cellular and extra-cellular blood components. We broadly apply these fundamental insights to demonstrate high-throughput separation of species ranging from micron-sized particles, to cancer cells, to extracellular materials. We also introduce a novel micro-fabrication method that can be readily scaled to enable mass production of filtration chips suitable for a host of cell enrichment and screening applications.