title: Fluidic conduits for highly efficient purification of target species in EWOD-driven droplet microfluidics.
abstract: Due to the lack of continuous flows that would wash unwanted specifies and impurities off from a target location, droplet microfluidics commonly employs a long serial dilution process to purify target species. In this work, we achieve high-purity separation for the case of electrowetting-on-dielectric (EWOD) based droplet microfluidics by introducing a "fluidic conduit" between a sample droplet and a buffer droplet. The long and slender fluidic path minimizes the diffusion and fluidic mixing between the two droplets (thus eliminating non-specific transport) but provides a conduit between them for actively transported particles (thus allowing the specific transport). The conduit is purely fluidic, stabilized chemically (e.g. using surfactants) and controlled by EWOD. The effectiveness of the technique is demonstrated by eliminating approximately 97% non-magnetic beads in just one purification step, while maintaining high collection efficiency (>99%) of magnetic beads.
authors.affiliation: UCLA, 420 Westwood Plaza, Engineering IV Bldg, Los Angeles, CA, USA90095, USA. gjshah@ucla.edu
authors.forename: Gaurav J
authors.initials: GJ
authors.lastname: Shah
authors.forename: Chang-Jin Cj
authors.initials: CJ
authors.lastname: Kim
mesh_terms: D017097:Electric Impedance; D004566:Electrodes; D005453:Fluorescence; D008280:Magnetics; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D020442:Poloxamer / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D013501:Surface-Active Agents; D020442:Poloxamer