Construction of refreshable microfluidic channels and electrophoresis along them

We proposed and demonstrated a “refreshable microfluidic channel.” This channel was constructed between two stacked glass slides with a 100 μm thick spacer. Each surface of the slides was frosted by being ground with an abrasive and made hydrophobic due to the treatment with 1,1,1,3,3,3-hexamethyldisilazane. A line was drawn on the surface using dimethyl sulfoxide (DMSO) as the ink. Because this DMSO line could work like priming water, a water solution flowed along the line and a channel formed, though there was no real groove on the surface. This channel could be easily erased by rinsing the slide with water. After drying the slide in air, we could reconstruct another channel on it. The channel widths that we actually obtained ranged from 470 to 950 μm. In addition, we demonstrated the electrophoresis of a dye (bromophenol blue) in the channel.