熱泳是一種顆粒在溫度梯度下移動的現象。若粒子在水中具有正索瑞特效應，則該粒子在溫度梯度下將由熱區移動至冷區。在此研究我們探討如何利用熱泳現象來濃縮和定量生物分子。我們使用近紅外光雷射(1064 nm)提供一溫度梯度來產生熱泳現象，並加入高分子聚合物聚乙二醇使熱泳現象反轉成顆粒由冷區移動至熱區。本研究發展一個方法可以讓螢光分子的熱泳運動隨著待測物濃度的改變而有較顯著的差異，使我們可以更準確地透過量測加熱區域周圍的螢光強度分布情形來測量待測分子的濃度。我們主要利用特殊DNA修飾的奈米金粒 (20 nm)與適體作為探針。本研究發展出兩種不同偵測的方式，一種為適用於核酸檢測，另一種為適用於蛋白質或其他小分子的檢測。實驗的結果顯示於核酸檢測時，熱區和周圍冷區的螢光強度差異隨著待測目標DNA濃度量增加而增加，而待測目標DNA之偵測濃度約在2 nM到20 nM之間；於蛋白質檢測時熱區與冷區的相對螢光強度則為隨著待測蛋白質的量增加而減少，而待測蛋白質之偵測濃度約在6 nM到300 nM之間。整體來說，我們成功地利用雷射提供一溫度梯度，使在聚乙二醇溶液內之熱泳效應聚集生物分子並利用螢光分子的螢光強度分布差異來定量不同濃度的核酸和蛋白質。

Thermophoresis is a phenomenon about the migration of particles in a temperature gradient. Particles with positive Soret effect move to cold regions in a thermal gradient. In this study we investigate how to use thermophoresis to concentrate and quantify biomolecules. Near infrared laser (1064 nm) is used to provide a temperature gradient to generate thermophoretic effects in the buffer solution, in which polyethylene glycol (PEG) is added to make the direction of the thermophoretic motion to be toward the heated region. This study developed a way to make the thermophoretic behavior of fluorescent molecule change with the concentration of the target molecules significantly, so that we can more accurately quantify target molecules by measuring the distribution of fluorescence intensity between heated area and non-heated area. DNA functionalized gold nanoparticles (AuNPs) and aptamer are used as probe to detect molecules. This study developed two different detection mechanisms, one is applicable to nucleic acid; the other is applicable to proteins or other small molecules. The results show that the intensity difference between the heated region and the surrounding region is higher when the concentration of the target DNA increases, but protein decreases. Under our experimental condition, the DNA detection is most sensitive when the concentration of the target DNA is between 2 nM and 20 nM, and protein detection is between 6 nM and 300 nM. In conclusion, we have successfully utilized thermophoresis to accumulate and quantify biomolecules. We accumulate the molecules by simply using laser irradiation and determine the concentration of the target molecules based on the image captured after thermophoretic accumulation.

1. Ross, D.; Gaitan, M.; Locascio, L. E. Analytical Chemistry 2001, 73, (17), 4117-4123.
2. Jiang, H.-R.; Wada, H.; Yoshinaga, N.; Sano, M. Physical Review Letters 2009, 102, (20).
3. Duhr, S.; Braun, D. Proceedings of the National Academy of Sciences of the United States of America 2006, 103, (52), 19678-82.
4. Reineck, P.; Wienken, C. J.; Braun, D. Electrophoresis 2010, 31, (2), 279-86.
5. Piazza, R. Soft Matter 2008, 4, (9), 1740.
6. Braibanti, M.; Vigolo, D.; Piazza, R. Physical Review Letters 2008, 100, (10).
7. Würger, A. Physical Review Letters 2009, 102, (7).
8. de Gans, B.-J.; Kita, R.; Müller, B.; Wiegand, S. The Journal of Chemical Physics 2003, 118, (17), 8073.
9. Luettmer-Strathmann, J. The Journal of Chemical Physics 2003, 119, (5), 2892-2902.
10. Würger, A. Reports on Progress in Physics 2010, 73, (12), 126601.
11. Yang, M.; Ripoll, M. Journal of physics. Condensed matter : an Institute of Physics journal 2012, 24, (19), 195101.
12. Maeda, Y. T.; Buguin, A.; Libchaber, A. Physical Review Letters 2011, 107, (3).
13. Maeda, Y. T.; Tlusty, T.; Libchaber, A. Proceedings of the National Academy of Sciences of the United States of America 2012, 109, (44), 17972-7.
14. Braun, D.; Libchaber, A. Physical Review Letters 2002, 89, (18).
15. Duhr, S.; Braun, D. Physical Review Letters 2006, 97, (3).
16. Weinert, F. M.; Braun, D. Nano letters 2009, 9, (12), 4264-7.
17. Weinert, F.; Kraus, J.; Franosch, T.; Braun, D. Physical Review Letters 2008, 100, (16).
18. Weinert, F. M.; Braun, D. Journal of Applied Physics 2008, 104, (10), 104701.
19. Weinert, F. M.; Mast, C. B.; Braun, D. Physical chemistry chemical physics : PCCP 2011, 13, (21), 9918-28.
20. Odagiri, K.; Seki, K.; Kudo, K. Soft Matter 2012, 8, (25), 6775.
21. Deng, H. D.; Li, G. C.; Liu, H. Y.; Dai, Q. F.; Wu, L. J.; Lan, S.; Gopal, A. V.; Trofimov, V. A.; Lysak, T. M. Optics express 2012, 20, (9), 9616-23.
22. Weinert, F.; Braun, D. Physical Review Letters 2008, 101, (16).
23. Duhr, S.; Braun, D. Applied Physics Letters 2005, 86, (13), 131921.
24. Baaske, P.; Wienken, C. J.; Reineck, P.; Duhr, S.; Braun, D. Angewandte Chemie 2010, 49, (12), 2238-41.
25. Wienken, C. J.; Baaske, P.; Rothbauer, U.; Braun, D.; Duhr, S. Nature communications 2010, 1, 100.
26. Seidel, S. A.; Wienken, C. J.; Geissler, S.; Jerabek-Willemsen, M.; Duhr, S.; Reiter, A.; Trauner, D.; Braun, D.; Baaske, P. Angewandte Chemie 2012, 51, (42), 10656-9.
27. Lippok, S.; Seidel, S. A.; Duhr, S.; Uhland, K.; Holthoff, H. P.; Jenne, D.; Braun, D. Anal Chem 2012, 84, (8), 3523-30.
28. Seidel, S. A.; Dijkman, P. M.; Lea, W. A.; van den Bogaart, G.; Jerabek-Willemsen, M.; Lazic, A.; Joseph, J. S.; Srinivasan, P.; Baaske, P.; Simeonov, A.; Katritch, I.; Melo, F. A.; Ladbury, J. E.; Schreiber, G.; Watts, A.; Braun, D.; Duhr, S. Methods 2013, 59, (3), 301-15.
29. Jerabek-Willemsen, M.; Wienken, C. J.; Braun, D.; Baaske, P.; Duhr, S. Assay and drug development technologies 2011, 9, (4), 342-53.
30. Wienken, C. J.; Baaske, P.; Duhr, S.; Braun, D. Nucleic acids research 2011, 39, (8), e52.
31. Instruments of using microscale thermophoresis (MST) were commercial released by NanoTemper Technologies. www.nanotemper-technologies.com/
32. Tiwari, P.; Vig, K.; Dennis, V.; Singh, S. Nanomaterials 2011, 1, (1), 31-63.
33. Han, K.; Liang, Z.; Zhou, N. Sensors 2010, 10, (5), 4541-57.
34. Chang, C. C.; Lin, S.; Lee, C. H.; Chuang, T. L.; Hsueh, P. R.; Lai, H. C.; Lin, C. W. Biosensors & bioelectronics 2012, 37, (1), 68-74.
35. Liu, Y.; Tuleouva, N.; Ramanculov, E.; Revzin, A. Analytical Chemistry 2010, 82, (19), 8131-8136.
36. Tuleuova, N.; Jones, C. N.; Yan, J.; Ramanculov, E.; Yokobayashi, Y.; Revzin, A. Analytical Chemistry 2010, 82, (5), 1851-1857.
37. Diel, R.; Goletti, D.; Ferrara, G.; Bothamley, G.; Cirillo, D.; Kampmann, B.; Lange, C.; Losi, M.; Markova, R.; Migliori, G. B.; Nienhaus, A.; Ruhwald, M.; Wagner, D.; Zellweger, J. P.; Huitric, E.; Sandgren, A.; Manissero, D. The European respiratory journal 2011, 37, (1), 88-99.
38. Pai, M.; Riley, L. W.; Colford, J. M. The Lancet Infectious Diseases 2004, 4, (12), 761-776.
39. Xu, S.; Yuan, H.; Xu, A.; Wang, J.; Wu, L. Langmuir : the ACS journal of surfaces and colloids 2011, 27, (22), 13629-34.
40. Erickson, D.; Sinton, D.; Li, D. Lab on a chip 2003, 3, (3), 141-9.
41. Samy, R.; Glawdel, T.; Ren, C. L. Anal Chem 2008, 80, (2), 369-75.
42. Baaske, P.; Duhr, S.; Braun, D. Applied Physics Letters 2007, 91, (13), 133901.