本論文樣品預集中裝置是利用陽離子水凝膠替代奈米管道，並在玻璃表面定義出水凝膠管道形狀，再與帶有微米管道之PDMS接合，製造整合奈米與微米管道系統。當施加電場於此奈微米晶片時，由於膠內孔徑的電雙層重疊現象，使得聚合膠內部產生離子選擇之特性，此特性造成奈米管道內部正、負離子通量之差異，形成奈、微米介面處濃度極化之效應。
本文利用陽離子水凝膠離子之選擇特性，正離子通量大於負離子通量。當施加電壓於奈微米管道時，陽極端可觀察到離子消散區形成，而在離子消散區與電滲流流場交接處有一電場降幅區，利用電場降幅使離子累積，達到濃度預集中之目的。文中設計三種不同的流道設計討論螢光累積程度，分別為偏壓管道，單一管道及縮小管道，並設計改變螢光聚集之多重管道，使晶片可同時有不同濃度累積。
在設計中，偏壓管道此設計可以將樣品集中後以偏壓帶動流體送至檢測槽，此裝置聚集程度約100倍。單一管道簡化偏壓管道設計，聚集程度可達80倍，並利用此設計製作多重平行管道。而縮小管道是在單一管道中間縮小寬度，在不同流速之影響可將樣品集中在更小的區域，在縮小單位面積下螢光濃度提高，此設計聚集程度可增加至200倍，聚集濃度可將100 nM的螢光濃度增加至2 μM螢光濃度。樣品預集中改變深度的影響下，發現深管道聚集至100倍需花費420秒，而淺管道聚集至200倍花費120秒易於觀察聚集現象。另外聚集效應發生在多重管道下，使用垂直膜在每根管道可聚集相同濃度；將膜傾斜45度角可觀察管道中的濃度差。

This study proposes a preconcentration device using a cation hydrogel polymer instead of a nanochannel in microfludic chips. The hydrogel near the micro- and nano-junction is printed on a glass substrate by patterning techniques. The hydrogel polymers perform a function similar to nanochannel. The system of micro/nano channels is fabricated by bonding a PDMS microchannel and hydrogel on the surface of a printed glass substrate. When an electric field is applied to the preconcentration chip, the ion-selective membrane has a characteristic of flux difference of cation and anion due to the overlap double layer effect in the nanochannel. Concentration polarization phenomena causes the concentration gradient near the membrane.
This study uses the ion-selective membrane, in which the flux of cation is larger than the flux of anion. At the anodic side, the ion depletion zone can be induced by applying voltage. The ion accumulation is induced by the difference of electro-migration at the border between the depletion zone and electroosmosis flow. We design three preconcentration devices to discuss ion accumulation: a voltage bias, and straight-/convergent-microchannel, and multiple microchannels.
The voltage bias device has at least three reservoirs and samples can be transported to the detection reservoir by electro-osmosis flow. A preconcentration factor 100-fold was achieved within 300 sec for this device. The straight microchannel has only two reservoirs and can easily fabricate to form multiple channels. A preconcentration factor can reach 80-fold in 120 sec. For the convergent-/divergent microchannel, area variation will change the velocity. Sample can be concentrated in a smaller area region. A preconcentration factor reached 200-fold can be achieved, i.e., for the concentration of 100 nM can be concentrated to 20 μM.　In the effect of depth, the concentration in the depth of 50 μm microchannel can reach 100-fold with 420 sec, and 200-fold for a shallow microchannelcan be achieved in 120 sec. For the multiple microchannel case, similar sample preconcentrations are observed if the hydrogel junction is placed vertically to the microchannels. When the membrane is placed 45˚ to the microchannels, variations in sample preconcentration are shown.

1. Manz, A., Graber, N., and Widmer, H. M., Miniaturized total chemical-analysis systems – a novel concept for chemical sensing. Sensors and Actuators B-Chemical, 1990. 1(1-6): p. 244-248.
2. Jacobson, S. C. and Ramsey, J. M., Microchip electrophoresis with sample stacking. Electrophoresis, 1995. 16(4): p. 481-486.
3. Everaerts, F. M., Verheggen, Tpem, and Mikkers, F. E. P., Determination of substances at low concentrations in complex-mixtures by isotachophoresis with column coupling. Journal of Chromatography, 1979. 169(FEB): p. 21-38.
4. Astorga-Wells, J. and Swerdlow, H., Fluidic preconcentrator device for capillary electrophoresis of proteins. Analytical Chemistry, 2003. 75(19): p. 5207-5212.
5. Hofmann, O., Che, D. P., Cruickshank, K. A., and Muller, U. R., Adaptation of capillary isoelectric focusing to microchannels on a glass chip. Analytical Chemistry, 1999. 71(3): p. 678-686.
6. Quirino, J. P. and Terabe, S., Exceeding 5000-fold concentration of dilute analytes in micellar electrokinetic chromatography. Science, 1998. 282(5388): p. 465-468.
7. Khandurina, J., Jacobson, S. C., Waters, L. C., Foote, R. S., and Ramsey, J. M., Microfabricated porous membrane structure for sample concentration and electrophoretic analysis. Analytical Chemistry, 1999. 71(9): p. 1815-1819.
8. Rubinstein, I. and Shtilman, L., Voltage against current curves of cation-exchange membranes. Journal of the Chemical Society-Faraday Transactions Ii, 1979. 75: p. 231-246.
9. Dukhin, S. S. and Mishchuk, N. A., Intensification of Electrodialysis Based on Electroosmosis of the 2nd Kind. Journal of Membrane Science, 1993. 79(2-3): p. 199-210.
10. Rubinstein, I. and Zaltzman, B., Electro-osmotically induced convection at a permselective membrane. Physical Review E, 2000. 62(2): p. 2238-2251.
11. Pu, Q. S., Yun, J. S., Temkin, H., and Liu, S. R., Ion-enrichment and ion-depletion effect of nanochannel structures. Nano Letters, 2004. 4(6): p. 1099-1103.
12. Kim, S. H., Wang, Y. C., Lee, J. H., Jang, H., and Han, J., Concentration Polarization and Nonlinear Electrokinetic Flow near a Nanofluidic Channel. Physical Review Letters, 2007. 99(4).
13. Kim, S. J., Song, Y. A., and Han, J., Nanofluidic concentration devices for biomolecules utilizing ion concentration polarization: theory, fabrication, and applications. Chemical Society Reviews, 2010. 39(3): p. 912.
14. Mao, P. and Han, J., Fabrication and characterization of 20 nm planar nanofluidic channels by glass–glass and glass–silicon bonding. Lab on a Chip, 2005. 5(8): p. 837.
15. Mao, P. and Han, J., Massively-parallel ultra-high-aspect-ratio nanochannels as mesoporous membranes. Lab on a Chip, 2009. 9(4): p. 586.
16. Lee, J. H., Song, Y. A., and Han, J., Multiplexed proteomic sample preconcentration device using surface-patterned ion-selective membrane. Lab on a Chip, 2008. 8(4): p. 596.
17. Kim, S. J. and Han, J., Self-sealed vertical polymeric nanoporous-junctions for high-throughput nanofluidic applications (vol 80, pg 3507, 2008). Analytical Chemistry, 2008. 80(18): p. 7179-7179.
18. Song, S., Singh, A. K., and Kirby, B. J., Electrophoretic concentration of proteins at laser-patterned nanoporous membranes in microchips. Analytical Chemistry, 2004. 76(15): p. 4589-4592.
19. Wang, Y. C., Stevens, A. L., and Han, J. Y., Million-fold preconcentration of proteins and peptides by nanofluidic filter. Analytical Chemistry, 2005. 77(14): p. 4293-4299.
20. Lee, J. H., Song, Y. A., and Han, J. Y., Multiplexed proteomic sample preconcentration device using surface-patterned ion-selective membrane. Lab on a Chip, 2008. 8(4): p. 596-601.
21. Huang, K. D. and Yang, R. J., A nanochannel-based concentrator utilizing the concentration polarization effect. Electrophoresis, 2008. 29(24): p. 4862-4870.
22. Mishchuk, N. A., The role of water dissociation in concentration polarisation of disperse particles. Colloids and Surfaces a-Physicochemical and Engineering Aspects, 1999. 159(2-3): p. 467-475.
23. Huang, K. D. and Yang, R. J., Formation of ionic depletion/enrichment zones in a hybrid micro-/nano-channel. Microfluidics and Nanofluidics, 2008. 5(5): p. 631-638.
24. Kim, P., Kim, S. J., Han, J., and Suh, K. Y., Stabilization of Ion Concentration Polarization Using a Heterogeneous Nanoporous Junction. Nano Letters, 2010. 10(1): p. 16-23.
25. Chun, H. G., Chung, T. D., and Ramsey, J. M., High Yield Sample Preconcentration Using a Highly Ion-Conductive Charge-Selective Polymer. Analytical Chemistry, 2010. 82(14): p. 6287-6292.
26. Ko, S. H., Kim, S. J., Cheow, L. F., Li, L. D., Kang, K. H., and Han, J., Massively parallel concentration device for multiplexed immunoassays. Lab on a Chip, 2011. 11(7): p. 1351-1358.
27. Rubinshtein, I., Zaltzman, B., Pretz, J., and Linder, C., Experimental verification of the electroosmotic mechanism of overlimiting conductance through a cation exchange electrodialysis membrane. Russian Journal of Electrochemistry, 2002. 38(8): p. 853-863.
28. Dhopeshwarkar, R., Li, S. A., and Crooks, R. M., Electrokinetic concentration enrichment within a microfluidic device using a hydrogel microplug. Lab on a Chip, 2005. 5(10): p. 1148-1154.
29. Dhopeshwarkar, R., Crooks, R. M., Hlushkou, D., and Tallarek, U., Transient effects on microchannel electrokinetic filtering with an ion-permselective membrane. Analytical Chemistry, 2008. 80(4): p. 1039-1048.
30. Zangle, T. A., Mani, A., and Santiago, J. G., On the Propagation of Concentration Polarization from Microchannel-Nanochannel Interfaces Part II: Numerical and Experimental Study. Langmuir, 2009. 25(6): p. 3909-3916.
31. Mani, A., Zangle, T. A., and Santiago, J. G., On the Propagation of Concentration Polarization from Microchannel-Nanochannel Interfaces Part I: Analytical Model and Characteristic Analysis. Langmuir, 2009. 25(6): p. 3898-3908.
32. Zangle, T. A., Mani, A., and Santiago, J. G., Effects of Constant Voltage on Time Evolution of Propagating Concentration Polarization. Analytical Chemistry, 2010. 82(8): p. 3114-3117.
33. Hunter, R. J., Zeta Potential in Colliod Science: Principles and Applications. 1981, New York: Academic Press.
34. Probstein, R. F., Physicochemical hydrodynamics: an Introduction (2nd ed.). 1994, New York: John Wiley and Sons.
35. Strathmann, H, Ion-Exchange Membrane Separation Processes. 2004, Amsterdam: Elsevier.
36. Schoch, R. B., Han, J., and Renaud, P., Transport phenomena in nanofluidics. Reviews of Modern Physics, 2008. 80(3): p. 839-883.
37. Janiak, D. S., Ayyub, O. B., and Kofinas, P., Effects of Charge Density on the Recognition Properties of Molecularly Imprinted Polymeric Hydrogels. Macromolecules, 2009. 42(5): p. 1703-1709.
38. Pourjavadi, A., Ghasemzadeh, H., and Mojahedi, F., Swelling Properties of CMC-g-Poly (AAm-co-AMPS) Superabsorbent Hydrogel. Journal of Applied Polymer Science, 2009. 113(6): p. 3442-3449.
39. SU-8 permanent epoxy negative photoresist processing guidelines for SU-8 2-25, SU-8 2000, Corp, Micro-Chem., Editor.
40. Bhattacharya, S., Datta, A., Berg, J. M., and Gangopadhyay, S., Studies on surface wettability of poly(dimethyl) siloxane (PDMS) and glass under oxygen-plasma treatment and correlation with bond strength. Journal of Microelectromechanical Systems, 2005. 14(3): p. 590-597.
41. Xia, Y. N., Kim, E., and Whitesides, G. M., Micromolding of polymers in capillaries: Applications in microfabrication. Chemistry of Materials, 1996. 8(7): p. 1558-1567.
42. Kim, S. J., Li, L. D., and Han, J., Amplified Electrokinetic Response by Concentration Polarization near Nanofluidic Channel. Langmuir, 2009. 25(13): p. 7759-7765.