Buoyancy driven fluid motion, however, can also occur in closed loop geometries in response to either vertically or horizontally imposed temperature gradients. These systems offer the exciting possibility of generating unidirectional laminar flows along a closed path and can be harnessed to perform temperature sensitive biochemical reactions. All reagent molecules move in parallel offering precise control over residence times within the desired temperature zones. Characterization of the flow field within these loops shows that as the magnitude of the horizontal temperature gradient imposed across the loop is increased, the flow rate generated inside the loop also increases in a manner that scales with the Grashof number. We discuss design features and capabilities of these novel closed loop thermocycling devices to amplify gene sequences of varying lengths individually as well as in multiplex formats. We also investigate the generality of these systems to perform pumping with no moving parts and generating extensional flows in cross-slot geometries.
Journal: TechConnect Briefs
Volume: 1, Technical Proceedings of the 2005 NSTI Nanotechnology Conference and Trade Show, Volume 1
Published: May 8, 2005
Pages: 620 - 623
Industry sector: Sensors, MEMS, Electronics
Topic: Micro & Bio Fluidics, Lab-on-Chip