Abstract
We report platelet enrichment from whole blood in a novel radial pillar device (RAPID) recently developed by us. Isolation of platelets from whole blood is required for understanding of clotting and the diagnosis of various diseases (e.g. dengue, thrombocytopenia, etc.). Size-based separation of platelets from a background of other blood cells in passive microfluidic devices is extremely challenging as the red blood cells are highly deformable and can pass through gaps much smaller than their size. Pillar-based microfluidic devices get clogged very soon, or lack the selectivity required for size-based separation. RAPID combines the advantages of dead-end and cross-flow pillar devices. Self-unclogging is achieved in RAPID by continuous removal of RBCs through secondary cross flows. Our device is most suitable for enriching platelets from whole blood at low flow rates, thus avoiding platelet activation. We report clog-free operation of the device using whole blood for more than 8 hours, which is an extremely challenging feat for pillar-based devices.