請用此 Handle URI 來引用此文件: http://hdl.handle.net/11455/87959
標題: Burst Valves for Solution Handling on Thermoplastic Microfluidic Device
作者: 周昕澔
Hsin-Hao Chou
Jun-You Chen
Guan-Hua Chen
Chien-Fu Chen
關鍵字: burst valve
surface modification
摘要: Microfluidic system utilizes microchannels or flow patterns to crate nanoliter or below scale space for multifluidic manipulation, interaction and sensing. The manipulation of low volume of liquid consumption makes it possess the advantages including rapid diagnosis time, safe platform, decreased reagent cost and quantitative increase of the test numbers that are extremely helpful for precious clinical samples. In order to control the behavior of small amount of reagents, valves play an important role for solutions storage and preservation, flow of fluids guidance and sequential or parallel reagents delivery for biochemical fields.The most versatile on-chip valve was monolithic poly (dimethyl siloxane) (PDMS) valve proposed by Steven Quake. It well adopted the soft lithography technique to provide a low-cost, ease of fabrication and scalability method creating thousands to millions of integrated micromechanical valves that can automatically perform thousands of assays in parallel in one single chip. However, the expensive hardware required for regulating pressure to close valve constrained their popularity in resource constrained settings. In addition, the intrinsic material properties of PDMS such as gas permeability and solvent compatibility cause reagent leakage or surface swell via evaporation or dissolution by many common solvents affect its applications for long-term solution storage and in situ chemical synthesis, respectively.Thermoplastics such as cyclo olefin polymer (COP) offers another material option for microfluidic community due to its unique properties such as low water absorption, low oxygen and moisture permeability and low gas emission that eliminate the potential solution concentration changes caused by the reagents evaporation and absorbance when long processing time is needed. This is critical for chip-based immunoassay that needed hours for washing, incubation, blocking and signaling processes or commercial products that require long-term duration for transportation.In order to take the advantages of the thermoplastic properties, a strategy to fabricate disposable valves utilizing the bonding strength difference between solvent bonding and thermal bonding on COP chips for thermoplastic microfluidics has been proposed in this study. Surface modification utilizing ultraviolet/ozone (UVO) treatment on specific area is adopted to form oxidized layer through a lamination mask. This oxidized layer can significantly increase the resistance on COP surface to non-polar solvent, so when the mating chips are enclosed by solvent bonding, a tiny gap is formed at the UVO treated surface. This gap is further closed through thermal fusion bonding procedure and the bonding pressure difference between solvent and thermal bonding is served as a burst valve. In contrast to enhance the robustness and minimum the energy requirement for long-term storage, the burst valve is at off-state when the device is at rest or the disturbed pressure is below the thermal bonding strength. Reagents can be sealed without additional elastic membrane to avoid leakage. Different burst pressure of valve can be achieved by simply changing the pattern of UVO modified area between two discrete channels. Multiple valves with identical or different burst pressure can be simultaneously fabricated on a single chip without additional procedures. We believe the proposed platform possesses the potential being part of in vitro devices for affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free and deliverable to end-users diagnostic applications.
為了達到微量控制待測流體,閥門對於試劑的儲存以及保存、流體流動方向的控制、以及平行多工試劑的輸送等目的有存在的必要性。本研究將利用低吸水性、低氧氣與水氣穿透性、以及低氣體放射特性之熱塑性塑膠材料如cyclo olefin polymer(COP)熱塑性塑膠材料應用於閥門上,元件上局部區域先利用紫外臭氧處理COP元件表面後,在反應區域生長出一層會對非極性溶劑有阻抗性的薄氧化層,所以當元件使用溶劑接合來接合時,此紫外臭氧處理區域並不會接合因而形成一微小的縫隙,接著可以利用熱接合方式將此縫隙封閉住,由於兩種接合強度差異,使此設定之特定區域具備一次性壓力閥門特性。本報告所提出閥門在沒有外力作用下處於關閉的狀態,達到節省儲存試劑的能量需求,並且試劑能夠保存於儲水區而不需要其他致動彈性薄膜等避免溢漏等多餘裝置。不同驅動壓力的一次性閥門可藉由簡單改變紫外臭氧處理區域大小而同時製作於同一元件上,吾人相信此閥門具備便宜、使用介面友善、耐用、不需要額外設備且能夠直接送至終端使用者之元件其中構成成份的潛力。
URI: http://hdl.handle.net/11455/87959
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