高分子微流體元件之製作及其在微晶片電泳和微型反應器之應用

Abstract

本論文之主旨在利用各種高分子材料如壓克力、矽橡膠和光阻材料等進行微流體元件製造方法及應用研究。由於高分子材料本身具有適用於熱壓、灌鑄和模造等大量加工生產技術的特性，因此在取代玻璃晶片製造微流體元件上廣受矚目。本文中將闡述多種利用高分子材料製作微流體元件的構想與製作方法，並探討其應用於微晶片電泳和微型反應器應用之可行性。 首先，本研究中利用室溫硬化型的矽膠樹脂和其他高分子樹脂原料來進行微流體流道之製作，將矽晶片母版上的微流道，用灌鑄成型法翻模複製到一矽膠材質的模具上，再以其他高分子樹脂在此模具中進行灌鑄成型，成功地將微流道製作於所形成的高分子微晶片之中，此種製程可用以在實驗階段開發元件原型，亦可用以複製大量成本低廉的可拋棄式微流體元件。其次，微流道中的電滲流行為一直是影響微晶片電泳應用的一個重要條件，而電滲流現象取決晶片材質的表面性質，文獻研究中多數皆以表面塗層或化學改質的方法來調控其電滲流行為，本研究中則嘗試對整體晶片的性質加以改質，利用總體聚合法來合成共聚合物晶片，並加工成微流體元件，進行其表面性質和微流道中電滲流現象的探討。實驗中發現：藉由親水性單體的加入對壓克力晶片進行總體改質，結果將使得共聚合物晶片表面對水的接觸角測定值降低，亦即其親水性因改質而增加；至於電滲流淌度(μeo)則隨著親水性單體的增加而明顯增大，總體而言其電滲流增大現象雖有其共聚合比例上的限制，但親水性共聚物晶片較之未改質的壓克力晶片有明顯增大的趨勢，相較於傳統的表面改質技術，此法更可提供微流體元件中電滲流調控的另一快速有效方法。本研究有別於目前使用傳統液態光阻和濕式蝕刻等微影技術，改以乾膜光阻為結構材料，結合高分子塑膠原料，利用微顯影黃光製程和熱壓法研製微流體元件：製程中先以乾膜光阻結合薄膜基材，製作出具有可撓曲性之微流體晶片反應器，並以此微型反應器配合自製之晶片夾具，在微流道中進行聚苯胺的化學合成。最後，本研究中更以乾膜光阻為結構材料來製作微流體元件，並配合壓克力塑膠基材組裝供電化學偵測法使用之毛細管電泳微晶片，提供微晶片電泳之應用研究，其實驗結果顯示：使用此種電泳晶片，可在50秒鐘內成功分離多巴胺、兒茶酚和尿酸等分析物質，證明以乾膜光阻為結構材料應用於高分子電泳微晶片之研發製造具有極大之應用潛力。

Polymers are the most promising materials for fabrication of microfluidic devices since they are applicable for conventional mass replication technologies such as hot embossing, casting, and molding. In this paper, we demonstrate several polymer microfabrication technologies for fabricating microfluidic devices for microchip capillary electrophoresis and microreactor applications. First, a molding process using silicone mold and polymer resins for the casting and duplication of microchannels from a master template to plastic substrates is described. These silicone molds can be used repeatedly to replicate inexpensive and disposable polymeric microfluidic devices. Second, we describe an effective method for controlling the surface properties and performance of polymeric microchips by using a bulk copolymerization approach during the fabrication process. The loading of a hydrophilic modifier (2-hydroxyethyl methacrylate) has a dramatic effect on the contact angle and electroosmotic mobility (μeo) of the modified copolymer chips. This method is a simple and potentially useful approach toward preparing plastic chips that have different intrinsic bulk properties and electroosmotic flows in their microchannels. In addition, we demonstrate a simple, efficient, economical and environmentally friendly continuous method for preparing polyaniline in a water medium within a flexible dry-film-photoresist-based polymeric microreactor. Finally, we present a new approach for integration of electrophoresis microchips with electrochemical detector using dry film photoresist in conjunction with photolithographic and lamination techniques. Rapid and efficient separation of dopamine, catechol, and uric acid was achieved within 50 s at 200 V/cm in microchip capillary electrophoresis. Combined with this easily performed fabrication procedure, dry film photoresist can be considered as promising alternative materials for constructing microfluidic devices. This approach for miniaturized microchip with electrochemical detector is time- and cost-effective, which suggests that it has great potential for use in prototyping of disposable microscale analytical system.