Cylindrical multiphase interfaces in microfluidic channels for lab-on-a-chip

We demonstrate a novel method to create cylindrical multiphase interfaces within microfluidics. Such interfaces are formed and maintained solely by surface tension at physical boundaries within the channels for simpler fabrication, easier control, and better robustness. This structure promises a versatile enabling technology cylindrical interfaces between air and aqueous phases, between aqueous and organic liquids, and between different aqueous phases, have been realized. Channel pressure of 247 Pa was sustained by the formed cylindrical interfaces. Several devices were developed employing this cylindrical interface structure, and showed potentials in biological sensing, pharmaceutical studies, and other lab-on-a-chip applications. In one device, a debubbler demonstrated effective removal of bubbles in microchannels several nL to mL in volume. In another device, aqueous micro columns containing liquid crystal emulsions, which possess the potential of molecular level sensing, were formed in a micro channel.