AN IN SITU MICROMACHINED MIXER FOR MICROFLUIDIC ANALYTICAL SYSTEMS

摘要

The present invention relates to an in situ micromachined mixer (10) for microfluidic analytical systems. In a preferred embodiment, a 100 pL mixer (10) for liquids transported by electroosmotic flow (EOF) is described. Mixing was achieved in multiple intersecting channels (12, 14) with a bimodal width distribution and varying lengths. Five νm width channels (12) ran parallel to the direction of flow whereas larger 27νm width channels (14) ran back and forth through the network at a 45° angle. All channels (12, 14) were approximately 10 νm deep. It was observed that little mixing of confluent streams occurred in the 100 νm wide mixer (10) inlet channel where mixing would be achieved almost exclusively by diffusion. In contrast, mixing was complete after passage through the channel network in the ≈200 νm length mixer (10). Solvent composition was altered by varying the voltage on solvent reservoirs. The high efficiency attained in this mixer (10) was attributed to the presence of a 2 pL vortex in the center of the mixer (10). Video tracking of fluorescent particles with a fluorescence microscope allowed the position and volume of this vortex to be determined.