Reversible Switching of High-Speed Air−Liquid Two-Phase Flows Using Electrowetting-Assisted Flow-Pattern Change

Huh, Dongeun; Tkaczyk, Alan H.; Bahng, Joong Hwan; Chang, Yu Cheng; Wei, Hsien Hung; Grotberg, James B.; Kim, Chang‐Jin; Kurabayashi, Katsuo; Takayama, Shuichi

doi:10.1021/ja037350g

Cited by 80 publications

(66 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Initially, liquid is injected into the plug generator and focused by air flows to form a stable stratification of air and liquid (Fig. 3A) (51,52). When air is valved off, the liquid stream spreads instantaneously and progresses gradually into the culture chamber (Fig.…”

Section: Resultsmentioning

confidence: 99%

Acoustically detectable cellular-level lung injury induced by fluid mechanical stresses in microfluidic airway systems

Huh¹,

Fujioka²,

Tung³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

433

422

View full text Add to dashboard Cite

We describe a microfabricated airway system integrated with computerized air-liquid two-phase microfluidics that enables onchip engineering of human airway epithelia and precise reproduction of physiologic or pathologic liquid plug flows found in the respiratory system. Using this device, we demonstrate cellularlevel lung injury under flow conditions that cause symptoms characteristic of a wide range of pulmonary diseases. Specifically, propagation and rupture of liquid plugs that simulate surfactantdeficient reopening of closed airways lead to significant injury of small airway epithelial cells by generating deleterious fluid mechanical stresses. We also show that the explosive pressure waves produced by plug rupture enable detection of the mechanical cellular injury as crackling sounds.airway reopening ͉ small airway epithelial cells ͉ mechanical forces ͉ microfluidic cell culture

show abstract

Section: Resultsmentioning

confidence: 99%

Acoustically detectable cellular-level lung injury induced by fluid mechanical stresses in microfluidic airway systems

Huh¹,

Fujioka²,

Tung³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

433

422

View full text Add to dashboard Cite

show abstract

“…One of the critical challenges in a microfluidic platform is the process for bio-particle selection, for example by filtration, fractionation, separation or sorting 3,4 . Initial efforts were focused on the miniaturization of fluorescence activated cell sorting (FACS) using microfluidic technology [5][6][7][8][9][10] , or other active energy based switching approaches [11][12][13][14][15][16] . However, these systems are highly complex and resulting microfluidic platforms have been difficult to integrate.…”

Section: Introductionmentioning

confidence: 99%

Soft inertial microfluidics for high throughput separation of bacteria from human blood cells

et al. 2009

View full text Add to dashboard Cite

We developed a new approach to separate bacteria from human blood cells based on soft inertial force induced migration with flow defined curved and focused sample flow inside a microfluidic device. This approach relies on a combination of an asymmetrical sheath flow and proper channel geometry to generate a soft inertial force on the sample fluid in the curved and focused sample flow segment to deflect larger particles away while the smaller ones are kept on or near the original flow streamline. The curved and focused sample flow and inertial effect were visualized and verified using a fluorescent dye primed in the device. First the particle behaviour was studied in detail using 9.9 and 1.0 µ m particles with a polymer-based prototype. The prototype device is compact with an active size of 3 mm 2 . The soft inertial effect and deflection distance were proportional to the fluid Reynolds number (Re) and particle Reynolds number (Re p ), respectively. We successfully demonstrated separation of bacteria (Escherichia coli) from human red blood cells at high cell concentrations (above 10 8 /mL), using a sample flow rate of up to 18 µL/min. This resulted in at least a 300-fold enrichment of bacteria at a wide range of flow rates with a controlled flow spreading. The separated cells were proven to be viable.Proteins from fractions before and after cell separation were analyzed by gel electrophoresis and staining to verify the removal of red blood cell proteins from the bacterial cell fraction. This novel microfluidic process is robust, reproducible, simple to perform, and has a high throughput compared to other cell sorting systems. Microfluidic systems based on these principles could easily be manufactured for clinical laboratory and biomedical applications.3

show abstract

“…A similar trend of variation in the oscillation amplitude for contact angle is also observed in this figure. For example, local peaks of oscillation amplitude for contact angle are reached around the resonance frequencies (12 • at 40 and 117 Hz), while nadir values are encountered away from the resonance frequencies (7 • at 85 Hz and 4.5…”

Section: Figure 10mentioning

confidence: 99%

“…Electrowetting on dielectric (EWOD) avoids the electrolysis of the aqueous solution in EW by coating the electrode surface with a thin dielectric layer. EWOD has been widely used in various applications, including microfluidics [3,4], liquid display [5,6], and microswitches [7,8].…”

mentioning

confidence: 99%

Numerical simulation of drop oscillation in AC electrowetting

Zhang

2013

Sci. China Phys. Mech. Astron.

View full text Add to dashboard Cite

In this paper, a "macroscopic-scale" numerical method for drop oscillation in AC electrowetting is presented. The method is based on a high-fidelity moving mesh interface tracking (MMIT) approach and a "microscopic model" for the moving contact line. The contact line model developed by Ren et al. [Phys Fluids, 2010, 22: 102103] is used in the simulation. To determine the slip length in this model, we propose a calibration procedure using the experimental data of drop spreading in DC electrowetting. In the simulation, the frequency of input AC voltage varies in a certain range while the root-mean-square value remains fixed. The numerical simulation is validated against the experiment and it shows that the predicted resonance frequencies for different oscillation modes agree reasonably well with the experiment. The origins of discrepancy between simulation and experiment are analyzed in the paper. Further investigation is also conducted by including the contact angle hysteresis into the contact line model to account for the "stick-slip" behavior. A noticeable improvement on the prediction of resonance frequencies is achieved by using the hysteresis model. Electrowetting (EW) is a phenomenon in which the wettability of a droplet on an insulator-coated electrode surface is modified by externally applying electrical voltages. This phenomenon originates from the electrostatic force, which is a direct consequence of the excess charge at the three-phase contact line [1]. A comprehensive review on EW, in both theory and experiment, was presented in the paper by Mugele and Baret [2]. EW can be used to manipulate small volume of liquid very fast and efficiently, with relatively low electrical potential and power consumption. Electrowetting on dielectric (EWOD) avoids the electrolysis of the aqueous solution in EW by coating the electrode surface with a thin dielectric layer. EWOD has been widely used in various applications, including microfluidics [3,4], liquid display [5,6], and microswitches [7,8]. Both DC and AC fields can be used in EW or EWOD.*Corresponding author (email: zhangx@lnm.imech.ac.cn)When a DC field is used, a new equilibrium state with a smaller contact angle will be reached after a spontaneous spreading process. If an AC field is used instead, more interesting and complex features are observed. At low-frequency AC excitation, the hydrodynamic response can follow the periodic change of the electric force at the contact line and the shape oscillation of droplet is observed. If the AC frequency exceeds a critical value for the hydrodynamic response, the droplet behaves just as if it is excited by a DC field. The final state of contact angle and shape depends only on the time-averaged value of the applied voltage. Recently, drop oscillation in AC EW at low frequencies (10-300 Hz) was studied by experiment and theory [9][10][11]. The experiments revealed that the drop oscillation became resonant at certain input AC frequencies and the pattern of shape oscillation was different at each resonance frequency. Th...

show abstract

Reversible Switching of High-Speed Air−Liquid Two-Phase Flows Using Electrowetting-Assisted Flow-Pattern Change

Cited by 80 publications

References 10 publications

Acoustically detectable cellular-level lung injury induced by fluid mechanical stresses in microfluidic airway systems

Acoustically detectable cellular-level lung injury induced by fluid mechanical stresses in microfluidic airway systems

Soft inertial microfluidics for high throughput separation of bacteria from human blood cells

Numerical simulation of drop oscillation in AC electrowetting

Contact Info

Product

Resources

About