Droplet-based nano/picoliter mixer using hydrophobic microcapillary vent

A mixing device for liquid droplets with pL-nL volume was developed for the first time. Two droplets with volume of 5 nL were pneumatically manipulated and joined together in a microchannel. For drawing off the air between two droplets, Hydrophobic Microcapillary Vent (HMCV)-a vent valve driven by the negative capillary action-was utilized. The mixer can be used as a diffusion-based optical chemical detector, or as a basic component in integrated multistep Micro Total Analysis Systems (/spl mu/TAS). Since the mixer has planar structure without moving parts, it can be fabricated by molding technique at low cost.