自組裝薄膜在生醫微流道表面力之應用研究

A Study of Surface Force on Self-Assembled Monolayer of Bio-Microchannel

黃展輝(Chan-Hui Huang)

指導教授 ： 洪政豪

國立虎尾科技大學/工程學院/機械與機電工程研究所/碩士(2009年)

https://doi.org/10.6827/NFU.2009.00040

摘要

微小化一直是光電、半導體等高科技相關產業努力的目標，近幾年來在微製造與分子生物領域的快速發展，使得結合製程光電與生物科學的跨領域應用日議程，人類急待解決的醫學、能源等問題漸露曙光。其中微流道是生醫晶片、燃料電池、微電子熱傳等領域廣泛應用的一種結構，因此研究微流道中的流體流動現象將對產業的發展有相當助益。
對生醫微流道晶片要求而言，檢測液體的流動速率是一大影響關鍵，故本實驗之研究主軸為：1.增進檢體流動速率2.降低檢體與微流道表面間的黏著，使流至待測區之檢體量增多，提升其準確性，這也是當前生醫晶片急欲解決之問題。本論文使用有機矽烷類自組裝單分子膜HDT、ODT、OTS、ODS於生醫微流道晶片上，希望能提高檢體生醫微流道晶片上之流動性與準確性。實驗結果顯示，接觸角實驗中四種自組裝膜接觸角皆隨浸泡時間增加而增加，並以OTS薄膜在不同浸泡時間皆大於100°且在24小時呈現最佳性能，因此在疏水性與抗沾黏性為較佳，此原因從FTIR實驗中，發現四種自組裝膜的CH3鍵結吸收峰強度皆隨浸泡時間增加而增加，而CH3與疏水性有關，因此OTS的接觸角上升與CH3鍵結吸收峰強度提高是有關係的，且OTS薄膜也隨浸泡時間上升黏附力下降，在12小時到達最佳性能趨於穩定。傾斜角實驗中，因為傾斜角藉由一個重力的影響來模擬實際流體流動的推力，比接觸角更能說明流體的流動性好壞，且發現流動性能HDT＞OTS＞ODT＞ODS，且發現與摩擦係數有相同趨勢。而在蛋白質濃度檢測發現，OTS、ODS與HDT黏著量都有下降又以OTS較為明顯，推測OTS自組裝膜可讓蛋白質黏著在表面數量下降，當應用於檢測時就可減少檢體吸附在微流道上，讓檢測準確性提高。為了進一步確認檢體實際流動狀況，利用螢光訊號測試CD-ELISA圓盤上流動狀態，實驗中發現以OTS與ODS電壓訊號值較高，顯見其檢測液體流至待測區含量較多所以螢光值升高，結果為OTS檢測出的檢體含量最佳。經驗證OTS24在各項儀器與螢光訊號試驗後，性能為組裝在生醫微流道晶片上最好，其結果能減少生醫微流道之黏附力，並增進生醫晶片檢測效果與準確性。

關鍵字

微流道 ； 生醫晶片 ； 自組裝薄膜 ； 黏附力 ； 表面力

並列摘要

Microminiaturization has been a target of photoelectricity, semiconductor and other high-tech related industries. In recent years, the rapid development in the area of microfabrication and molecular biology has lead to the growth of interdisciplinarity application which combined production process of photoelectricity and biological sciences. This would render bright outlook for resolution of problems which need to be solved urgently. Microchannel is a design which can be comprehensively applied in the areas such as bio-chips, fuel cells, and microelectronic heat transmission. Therefore, research for the flowing phenomenon in the microchannel would be very much helpful for the development of industries.
As the flowing speed of specimen liquid is the prime factor for the requirement of bio-microchannel chips, therefore, the core components of this research are： 1. Accelerating flowing speed of specimens. 2. Lowering the adhesion between the specimens and the surfaces of microchannels to enable more volume of specimens flowing to the examination areas so as to increase accuracy. This is also deemed the first priority for bio-chips nowadays. In this paper, organic alkoxysilane Self-assembled monolayers such as HDT, ODT, OTS, and ODS were used for bio-microchannel chips, in order to increase flowing ability of specimens on the bio-microchannel chips and their accuracy. Results of contact angle experiments showed that contact angles of these 4 self-assembled layers increased with the advance of soaking times. Contact angles of OTS layers were all bigger than 100° in each soaking time. In 24 hours’ time especially, it presented the best function which suggested better hydrophobic property and anti-adhesion. The cause for the above could be found in the FTIR experiment where strength of absorbance peak of CH3 bonds increased with the advance of times in these 4 self-assembled layers. As CH3 was related with hydrophobic property, thus OTS’s increase in contact angle was also related with the strength increase of absorbance peak in CH3 bonds. Adhesion of OTS layers decreased with the advance of soaking time and achieved the best function and became stable in 12 hours. In the experiment of contact angles, single gravity was used to affect contact angles to simulate pushing power of actual flowing liquid. This had better illustrated flowing quality of liquid than contact angle. It was also found that HDT＞OTS＞ODT＞ODS in flowing ability and friction coefficient had the same trend. In the examination of protein concentration, it was found that adhesion of OTS, ODS, and HDT lowered, especially OTS, assuming that OTS self-assembled layers could lowered the surface adhesion of protein. In this case, it can reduce adhesion of specimens on the microchannel and increase accuracy of examination. In order to go further in examining actual flowing of specimens, fluorescence signal was used to test the flowing condition on the CD-ELISA plate. It was found in the experiment that OTS and ODS had higher voltage signal values which apparently indicated that more specimen liquid had flowed to the examination areas and raised the fluorescence values. The result showed that the best specimen volume observed was OTS. After verification with various instruments and fluorescence signal tests, OTS24 presented the best function when self-assembled on bio-microchannels, as it did reduce adhesion force of bio-microchannels and enhanced its effect and accuracy.

並列關鍵字

microchannel, bio-chip ； self-assembled monolayer ； adhesion force ； surface force

參考文獻

[1] L. Yu, Y. L. Juang, K. W. Koelling, and L. J. Lee, 2000, “Thin wall injection molding of thermoplastic microstructures,” SPE Tech. Papers,46,468.

[2] X. F. Peng and G. P. Peterson, 1996, “Convective Heat Transfer and Flow Friction for Water Flow in Micro channel Structures,” Int. J. Heat Mass Transfer,Vol. 39, No. 12, pp. 2599-2608.

[3] T.D. Boone, Z.H. Fan, H.H. Hopper, A.J. Ricco, H. Tan, S.J. Williams, “ Plastic Advances Microfluidic Devices,” Analytical Chemistry 2002, 74, 78A-86A.

[4] J.C McDonald, D.C. Duffy, J.R. Anderson, D.T. Chiu, H. Wu, O.J.A Schueller, G.M. Whitesides, 2000, “Fabrication of Microfludic Systems in Poly(dimethylsiloxane) ,” Electrophoresis 21, pp.27-40.

[5] Mark E.M., Krishna, M. R. K. and Michael, T., 1994, “Role of Solvent on the Silanization of Glass with Octadecyltrichlorosilane,” Langmuir 10, pp.3607-3614.