Microfluidic compact discs use centrifugal forces for propulsion and manipulation of fluid as it advances from the center of the disc to its rim. Centrifugal pumping is thus limited to outward flow thereby limiting the amount of space available to embed complex microfluidic networks. This report explores the uses of hydrostatic pressure and the Venturi effect as novel pumping mechanisms to expand fluidic path lengths within the CD by drawing fluid back towards the center of the disc.;The hydrostatic pressure pump manipulates fluid through a dynamic change in the pressure within a working channel. Theoretical modeling, describing the pressure drop along the main channel due to the change in hydrostatic head showed pressure generation was possible. The first application of this CD-based hydrostatic pressure pump is the priming of a novel siphon valve that primes due to the created negative pressure.;We utilize the Venturi effect to draw a sample fluid back towards the center of the microfluidic CD for cyclical or continuous pathway flow through the use of an off disc pressure source. A continuous pathway was established that allowed fluid to travel a full 360 degrees around a microfluidic disc. The first cyclical flow application is a filtering technique that can remove blue dye from water through a carbon filter. These added pumping mechanisms considerably expand the capabilities of the CD microfluidic platform to enable the implementation of more complex assays and a better utilization of the available surface area within a single disc.
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