To begin, place the microfluidic device into the bottom part of the test fixture. Align the top part of the fixture onto the device, and using two sets of nylon screws and nuts, assemble the two parts. Place the test fixture on the microscope stage.
Locate one desired set of electrodes under the microscope. Connect the corresponding pair of electrode wires that match the located electrode set to the output terminal of the function generator. Remove five microliters of the dielectrophoresis, or DEP medium, from the three-millimeter inlet of the microfluidic channel.
Using a 10-microliter pipette tip, slowly load five microliters of the prepared red blood cell, or RBC suspension, into the inlet and allow the cells to settle for one minute. Observe the channel under 20X magnification. Press the Sine button and define a sine wave with an amplitude of two volts root mean square at a frequency of three megahertz.
Press the Mod button to enable modulation. Press the Type option to change the wave mode into amplitude shift keying, or ASK. Set the modulation frequency to 250 megahertz, corresponding to a four-second loading/unloading period.
Turn on the Output of the function generator and record a one-minute video every 10 minutes at 30 frames per second. The RBCs spontaneously responded to the electrical excitation by moving towards edges of electrodes with higher field strength. Under the on-keying phase, RBCs were stretched due to electrode deformation, while under the off-keying phase, RBCs were relaxed.
When tracking individual RBCs during the one-hour fatigue testing, a gradual decrease in cellular deformation was observed.
