Biomedical Sensors and Subsystems

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Constant Flow-Driven Microfluidic Oscillator for Different Duty Cycles
Sung-Jin Kim, Ryuji Yokokawa, Sasha Cai Lesher-Perez, and Shuichi Takayama
Figure. (Left) Constant flow-driven microfluidic oscillator. To control duty cycle, the opening width of the valve is changed. (Right) Periodic staining of cell-nucleus. Fluorescent intensity-profile of a cell nucleus (see white arrow ) and the corresponding pressure profile at the source terminal of valve. Red region is valve-off state for the fluorescent solution, and clear solution flows during this time.
Figure. (Left) Constant flow-driven microfluidic oscillator. To control duty cycle, the opening width of the valve is changed. (Right) Periodic staining of cell-nucleus. Fluorescent intensity-profile of a cell nucleus (see white arrow ) and the corresponding pressure profile at the source terminal of valve. Red region is valve-off state for the fluorescent solution, and clear solution flows during this time.

Cells exist in highly dynamic environments consistently being exposed to biochemical and physical stimulation. For cell study, we work on microfluidic devices that autonomously convert two constant flow inputs into an alternating oscillatory flow output. We accomplish this hardware embedded self-control programming using normally closed membrane valves that have an inlet, an outlet, and a membrane-pressurization chamber connected to a third terminal. Adjustment of threshold opening pressures in these 3-terminal flow switching valves enable adjustment of oscillation periods to between 57–360 s with duty cycles of 0.2–0.5. We also try to show the ability to use these oscillators to perform temporally patterned delivery of chemicals to living cells. The device only needs a syringe pump, thus removing the use of complex, expensive external actuators. These tunable waveform microfluidic oscillators are envisioned to facilitate cell-based studies that require temporal stimulation.

Updated 05/02/2012