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Particle filtration and concentration have great significance in a multitude of applications. Physical filters are nearly indispensable in conventional separation processes. Similarly, microfabrication-based physical filters are gaining popularity as size-based particle sorters, separators, and prefiltration structures for microfluidics platforms. The work presented here introduces a linear combination of obstructions to provide size contrast-based particle separation. Polystyrene particles that are captured along the crossflow filters are packed in the direction of the dead-end filters. Separation of polydisperse suspension of 5 μm and 10 μm diameter polystyrene microspheres is attained with capture efficiency for larger particles as 95%. Blood suspension is used for biocharacterization of the device. A flow induced method is used to improve particle capture uniformity in a single microchannel and reduce microgap clogging to about 30%. This concept is extended to obtain semiquantification obtained by comparison of the initial particle concentration to captured-particle occupancy in a microfiltration channel.

Abstract. Point-of-care and low cost microfluidics platforms has found an accelerated research focus. One of the essential elements of microfluidics is driving liquid flow in microchannels. Device discussed gives a way to pump liquid passively through a microchannel. The present work represents fiber and paper based passive micro-pumping of liquids through microfluidic devices. The porous structure and network of capillaries inside the paper and fiber materials support spontaneous liquid movement. Agarose gel coating is used with paper in order to achieve variations flow rates. The effect of gel concentration on liquid flow is studied. The concept can be used ubiquitously for microfluidics device application for its low-cost and is feasible to integrate with devices for low resource settings.

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