Fig. 3: Fluidic applications demonstrating high channel-density parallelization and low-loss viral biosensing.

a A spiral-top electrode is patterned out of aluminum, with the bottom gold electrode colored yellow. A drop of PBS is positioned out of view. b Using the device shown in (a), spontaneous capillary flow is observed using a fluorescent dye due to a sidewall exceeding the capillary limit. The liquid channel travels ~684 µm from the drop. c After 3.5 V_RMS voltage is applied, the liquid channel wraps around the outer edge of the top electrode and travels an additional ~566 µm in 5 min., for a total length of ~1.25 mm from the drop and 5 µm in width. d An image of a sample chip with five droplets placed for actuation. The inset shows an SEM image of a dense line-array used for channel parallelization (scale bar = 5 µm). e, f Fluorescent image of parallel fluidic channels used to extrude FITC-labeled norovirus-like particles, before (e) and after (f) voltage is applied. Images were artificially colored magenta to distinguish from other experiments. g Infrared spectroscopy was used to confirm the presence of viral material within the channels compared with fluorescent background. Dips unique to the virus samples are circled in black. Source data are provided as a Source Data file. h Three parallel top electrodes with larger separation were used for particle filtration. i After applying 3.5 V_RMS, parallel microchannels formed along the edges of the top electrodes, as confirmed using fluorescent Alexa Fluor-594 molecules (red). Larger 190-nm polystyrene beads (green) spiked into the solution are filtered from entering the microchannels due to low-voltage dielectrophoresis.