藥物輸送系統之無閥式微氣泡截量元件研發

Abstract

微流體系統近年來在化學偵測、生醫檢測、藥物輸送等總體分析系統(TAS)上都有良好及廣大的應用。在微流道中能有效的阻斷流體，並具精確定量的方法，則是微流體系統中不可或缺的要素。 本研究使用表面張力的特性來驅動工作流體(水)，利用親水性與疏水性的材料製成微流道，讓流體無需要任何外加驅動力(電力、幫浦)即可進入流道。並設計一微加熱器，以通電壓加熱沸騰流體產生微氣泡閥的方式截斷微流道內的流體，此方法可代替以往複雜的機械閥門結構。在已知流道尺寸的情況下，將可達到精確定量截斷的效果。在改變微流道兩旁氣泡阻擋層的結構後，使得氣泡閥在電壓解除後仍能在流道中維持很長的時間。 本研究亦利用疏水性間隔與氣泡閥配合截取微量流體，並運用電場或加熱改變液體表面張力的方式，來驅動被截取的微量流體。如此可提供一個定量截斷流體並且有效輸送此微量液體的方法。未來此構想可與其他微元件整合於晶片上，而成為實用的微流體定量截斷與輸送系統。

In recent decades, the micro-fluid-system has been widely applied in the field of TAS (Total Analysis System) such like chemical detection, drug delivery, and biomedical diagnosis. Cutting fluid effectively and delivering exact amount of fluid are essential parts in a micro-fluid-system. This study introduces an effective method to drive DI water by means of the surface tension without introducing external devices or energy sources such as pumps or electric force. The micro channel is made of hydrophilic and hydrophobic materials. In addition, a micro heater has also been designed. With the electrical heating, the bubble generated in the liquid can block the water flowing in the channel and serve as a valve. This concept can replace the one involving complicated mechanical valves adopted before. Provided that the geometry of the micro channel is known, the volume of the fluid can be controlled. Furthermore, by modifying the pads at the sides of the channel, the bubble can stay unchanged for a period of time after the electric power has been removed. Thus, a tiny amount of water can be grabbed with the bubble-valve together with a hydrophobic gap across the channel. To transport this tiny amount of fluid, a driving force will be created to drive the tiny amount of fluid to cross the hydrophobic gap by modifying the surface tension with an electric field or heating. This is an innovative way to cut the liquid accurately and deliver the tiny drop effectively in a micro-channel system. Hopefully, in the future, this device can be batch-fabricated and be integrated to a lab-on-a-chip MEMS fluid system.