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標題: 於微流道量測液滴阻抗之實驗研究
Impedance measurements of droplets generated in a microfluidic device
作者: 林聖家
Lin, Sheng-Chia
關鍵字: 液滴;droplet;阻抗;微流道;impedance;microfluidic
出版社: 機械工程學系所
引用: 1. Cheung K., Gawad S., and Renaud P., “Impedance spectroscopy flow cytometry: on-chip label-free cell differentiation,” Cytometry Part A, Vol. 65A, 2005, 124-132. 2. Gawad S., Schild L., and Renaud Ph., “Micromachined impedance spectroscopy flow cytometer for cell analysis and particle sizing,” Lab on a chip, Vol. 1, 2001, 76-82. 3. Gardner J. W., Varadan V. K., Awadelkarim O. O., “Microsensors MEMS and Smart Devices,” JOHN WILEY & SONS, LTD, 2010. 4. Haeberle S., Zengerle R., and Ducree J., “Centrifugal generation and manipulation of droplet emulsions,” Microfluidics and Nanofluidics, Vol. 3, 2006, 65-75. 5. Holmes D., and Morgan H., “Single cell impedance cytometry for identification and counting of CD4 T-Cells in human blood using impedance labels,” Analytical Chemistry, Vol. 82, No. 4, 2010, 1455-1461. 6. Joo S., Kim K. H., Kim H. C., Chung T. D., “A portable microfluidic flow cytometer based on simultaneous detection of impedance and fluorescence,” Biosensors and Bioelectronics, Vol. 25, 2010, 1509-1515. 7. McDonald J. C., Duffy D. C., Anderson J. R., Chiu D. T., Wu H. K., Schueller O. J. A., and Whitesides G. M., “Fabrication of microfluidic systems in poly(dimethylsiloxane),” Electrophoresis, Vol. 21, 2000, 27-40. 8. Nasir M., Ateya D. A., Burk D., Golden J. P., and Ligler F. S., “Hydrodynamic focusing of conducting fluids for conductivity-based biosensors,” Biosensors and Bioelectronics, Vol. 25, 2010, 1363-1369. 9. Niu X., Zhang M., Peng S., Wen W., and Sheng P., “Real-time detection, control, and sorting of microfluidic droplets,” Biomicrofluidics, Vol. 1, 2007, 044101, 1-12. 10. Sun T., Bernabini C., and Morgan H., “Single-Colloidal particle impedance spectroscopy: complete equivalent circuit analysis of polyelectrolyte microcapsules,” Langmuir, Vol. 26, No. 6, 2010, 3821-3828. 11. Sun T., Holmes D., Gawad S., Green N. G., and Morgan H., “High speed multi-frequency impedance analysis of single particles in a microfluidic cytometer using maximum length sequences,” Lab on a chip, Vol. 7, 2007, 1034-1040. 12. Sun T., and Morgan H., “Single-cell microfluidic impedance cytometry: a review,” Microfluid Nanofluid, Vol. 8, 2010, 423–443. 13. Wang J. W., Wang M. H., and Jang L. S., “Effects of electrode geometry and cell location on single-cell impedance measurement,” Biosensors and Bioelectronics, Vol. 25, 2010, 1271-1276. 14. 郭名哲, 利用靜態與旋轉十字型微流道生成乳化液滴可視化實驗,國立中興大學碩士論文, 2009. 15. 簡百駿, 利用雙十字型微流道交替生成乳化液滴可視化實驗,國立中興大學碩士論文, 2011.
本實驗研究製作十字型流道,利用流體聚焦方式以氯化鉀(KCl)水溶液為消散相流體,而葵花油為連續相流體,擠壓生成液滴。實驗晶片是利用軟微影方法製作PDMS (Polydimethylsiloxane)微流道結構,並將翻模後的流道與電極晶片接合。藉由可視化平台觀察液滴生成的情形,當固定連續相流率為50 μl/hr,消散相的流率分別為50 μl/hr、75 μl/hr和100 μl/hr,液滴長度會隨著流率的增加而變長,並加快生成頻率。在阻值量測中,利用阻抗分析儀可量測出不同液滴長度的阻值變化,當液滴長度較長時,由於氯化鉀溶液相較於葵花油的導電性較佳,故阻值會降低,阻值比(Z*)也會隨之減少。在時序列訊號中,藉由液滴通過電極時對電磁場的干擾,我們可估算液滴的生成頻率,並由液滴的通過時間,可計算液滴長度,其結果與實際量測情形較為接近。

This experimental study employs the flow-focusing technique to produce droplets in cross microchannels. In the present experiments, oil is used as the continuous phase fluid and potassium chloride solution (0.5M) as the dispersed phase fluid. The microchannels are made of Polydimethylsiloxane (PDMS) using the soft lithography technique and bounded with electrode chip. The dispersed phase fluid rate was varied at 50 , 75 and 100 μl/hr, while the continuous phase fluid rate was fixed at 50 μl/hr. With increasing dispersed phase fluid rate, it is found that the plug-type droplets become longer in length and are generated at a higher frequency. An impedance analyzer was employed to measure the impedance change caused by the drops of different length passing through the electrodes. The impedance measured as well as the impedance ratio (Z*) are found reduced when the drop length become longer. This is an indication that conductivity of potassium chloride is greater than that of oil. The passage of drops through the electrodes also causes significant variation in the time-series signals due to interference in the electromagnetic field. As a result, the generation frequency and length of the drops can be estimated from the time-series data.
其他識別: U0005-2708201216564900
Appears in Collections:機械工程學系所

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