工學院: 應用力學研究所指導教授: 沈弘俊; 楊鏡堂葉思沂Yeh, Szu-ISzu-IYeh2017-03-062018-06-292017-03-062018-06-292014http://ntur.lib.ntu.edu.tw//handle/246246/277181本文利用生化分子自組裝技術進行微液珠操控，完整探討各種流體條件(表面張力、黏滯性)對液珠碰撞融合後流場及混合行為的影響，以簡單化學反應討論微液珠內部反應行為與流體混合行為的差異，並以化學反應以及DNA螢光共振(fluorescence resonance-energy transfer, FRET)實驗進行三重液珠碰撞之生化反應調控測試。數位微流體在生化、生醫領域的應用近年來快速發展，微尺度下，數位流體傳輸受到表面張力、黏滯性等流體性質的影響甚鉅，了解各種流體特性對液珠碰撞融合與混合行為的影響，是數位微流體系統發展過程中，重要的基礎研究。在此基礎上可將數位微流體有效應用於生化檢測裝置之性能提升，最終以達成檢體快速傳輸、混合與反應並完成檢測之目標，利於後續數位微反應器之應用與開發。 微液珠碰撞融合的瞬間會產生巨觀流動，但內部流場僅維持約100 ms，在此時間內液珠混合是由對流主導；流動靜止後液珠混合則是由擴散主導。其中對流主導之混合佔總混合效率60%以上。本文利用共軛焦顯微鏡(confocal microscopy)及微粒子影像測速儀(micro-PIV)，觀測微液珠融合過程中，內部非穩態三維濃度分布與內部流場型態，探討碰撞融合後所形成的流場及流場對混合行為、混合指標的影響。結果顯示，具相同表面張力之液珠，表面張力較大者有較好之混合效率；當液珠表面張力不同，液珠的碰撞順序將影響到其混合行為及最終混合效果，低表面張力液珠撞擊高表面張力液珠，可達到優於相反碰撞順序之混合效率。此結果可應用於設計最佳化之傳輸碰撞順序，提高生化液珠所攜檢體、試劑等之混合效率，可作為開發數位微流體系統之重要參考。本文另以高速攝影機(3200 fps)觀測兩液珠融合(coalescence)時，內部酸鹼中和反應造成的指狀化不穩定現象(fingers of instability)，以及利用三重液珠碰撞調整液珠流體成份與碰撞角度，控制融合液珠內部化學反應的初始時間與反應發生位置。結果顯示，液珠內的化學反應行為，與染料實驗的混合模式有很大的差異，指狀化不穩定現象將加速反應的進行，是微流體平台應用於生化檢測時的關鍵；三重液珠碰撞可達到液態膠囊(aquiform capsule)的效果，可有效調控生化檢測、細胞給藥的速率。 本文完整探討各種流體條件(表面張力、黏滯性)微液珠於開放表面上的碰撞融合、混合與反應行為；並提出流體混合行為與反應行為在時間與空間尺度上的各種差異，補足傳統上以流體混合效率預測反應趨勢的不足；有別於大多數研究希望能夠加快微流體系統的混合與反應，本文另提出抑制並調控生化反應發生時間與反應發生位置的概念，對於生醫檢測、細胞給藥實驗等領域有所助益。期望未來能將此平台，更有效並廣泛的應用於生化檢測裝置之性能提升，最終達成檢體傳輸、混合、反應並完成檢測之目標，以利於後續微反應平台之應用與開發。Digital microfluidics attracts much attention for its prospective applications to revolutionize biological laboratory procedures by allowing efficient assays with great versatility, small sample consumption and short detection duration. Droplets collision, colalescence and mixing behavior with different viscosities and surface tensions are the basic and important research in the development process of digital microfluidics. The aim of this study is to buildup the performance of bio-chemical detection device using droplet-based microfluidics. We manipulated the droplet on the self-assambled textured surface and investigated the different droplet coalescence profile, internal flow field inside the coalesced droplet, and mixing behavior inside the coalesced droplet caused by different characteristic (viscosity and surface tension) of fluids. We also investigated the difference of fluid mixing and reaction inside the droplet, and we show a simple and maneuverable method of digital microfluidics to modulate a biochemical reaction with a ternary droplet collision using a simple chemical reaction and DNA fluorescence resonance-energy transfer (FRET) test. We utilized micro-PIV and confocal microscopy to measure the coalescence process, internal flows, and mixing patterns of droplets with different viscosities and surface tensions after a head-on collision between a moving droplet and a stationary droplet on a wettability gradient surface. The results indicate that the mixing is driven sequentially by interior convection and diffusion once the two droplets touch each other; the convection endures less than 100 ms but dominates more than 60 % of the mixing. For the collision of droplets of identical surface tension, the surface tension affects the coalescence behavior; for the collision of droplets with distinct surface tension, the coalescence behavior and mixing quality depend on the colliding arrangement of stationary and moving droplets. We also used a high-speed camera to observe the color changing reaction inside a coalesced droplet. Compare to the traditional dye-mixing test, the chemical reaction inside the coalesced droplet facilitated the mixing of two counter-reactive fluids and was more than hundred times as efficient as the unreactive fluids mixing inside the coalesced droplet. Instead of mixing, chemical reaction inside a coalesced droplet is worth attention to the applications of digital microfluidic open-system. In droplet coalescence process, the characteristic of fluids and the ratio of volumes of two droplets caused different droplet coalescence profile especially the necking-curvature which affects the shape of the material interface between the two droplets in an initial phase. Capsules are used to protect, control and deliver drugs to the specific tissue. In recent year, multilayer microcapsules and nanocapsules are under review as multifunctional delivery systems. In this study, we also show a simple and maneuverable method to modulate the bio-chemical reaction for digital microfluidics on the surface by ternary droplet collision. The coalescence behavior and mixing quality are significantly concerned with the arrangement and configuration of different droplets on a droplet-based microfluidic system. This work significantly contributes to the understanding of droplet mixing and reaction in droplet-based microfluidic systems. Instead of mass transfer and mixing, chemical reaction inside a coalesced droplet is worth attention for digital microfluidic open-system. This work illustrates a correlation between the growth and evolution of chemical reaction and the profile (necking-curvature) of a coalesced droplet, which is also a significant reference in droplet-based microfluidic systems for biochemical use. Furthermore, the moduration of initial time and initial point of reaction inside the coalesced droplet is greater development potential on bio-chimical detection and cell-drug interaction test specifically.36749632 bytesapplication/pdf論文公開時間: 2020/2/3論文使用權限: 同意無償授權液珠碰撞液珠融合化學反應反應調控Droplet collisionDroplet coalescenceChemical reactionReaction controlthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/277181/1/ntu-103-F95543021-1.pdf