Abstract
The formation of emulsification droplets is crucial for many industrial applications. This paper reports a new microfluidic chip capable of formation and collection of micro-droplets in liquids for emulsion applications. This microfluidic chip comprising microchannels, a micro-chopper and a micro-switch was fabricated by using micro-electro-mechanical-systems (MEMS) technology. The microfluidic chip can generate uniform droplets with tunable sizes by using combination of flow-focusing and liquid-chopping techniques. The droplet size can be actively fine-tuned by controlling either the relative sheath/sample flow velocity ratios or the chopping frequency. The generated droplets can be then sorted to a specific collection area utilizing an active pneumatic micro-switch formed with three micro-valves. Experimental data showed that the olive oil and sodium-alginate (Na-alginate) droplets with diameters ranging from 3 μm to 70 μm with a variation less than 14% is successfully generated and collected. The development of this microfluidic system can be promising for emulsion, drug delivery and nano-medicine applications.
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Abbreviations
- DI water:
-
deionized water
- DNA:
-
deoxyribonucleic acid
- EMV:
-
electromagnetic valve
- MEMS:
-
micro-electro-mechanical-systems
- Na:
-
sodium
- PDMS:
-
polydimethylsiloxane
- SEM:
-
scanning electron microscope
- V 1 :
-
sheath flow velocity
- V 2 :
-
sample flow velocity
- o/w:
-
oil-in-water
- o/o/w:
-
oil-in-oil-in-water
- o/w/o:
-
oil-in-water-in-oil
- w/o:
-
water-in-oil
- w/o/w:
-
water-in-oil-in-water
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Acknowledgment
The authors gratefully acknowledge the financial support provided to this study from National Science Council in Taiwan (NSC 95-2221-E-006-150).
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Lai, CW., Lin, YH. & Lee, GB. A microfluidic chip for formation and collection of emulsion droplets utilizing active pneumatic micro-choppers and micro-switches. Biomed Microdevices 10, 749–756 (2008). https://doi.org/10.1007/s10544-008-9186-3
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DOI: https://doi.org/10.1007/s10544-008-9186-3