近年來生醫檢測技術朝實驗室晶片(Lab-on-a-chip, LOC)方向發展，將繁複的實驗過程簡化並濃縮在微晶片上，節省樣本並縮短時耗。非接觸式粒子操控技術將有利於晶片上的小體積樣本的微奈米等級操作。快速電動圖紋法(REP)是一個較新穎的光電動操控粒子技術，不需要高功率雷射、可自由操縱粒子，且晶片製程簡單。本研究欲以LOC的概念開發REP在生醫領域上的應用。
在病毒的研究當中，因為其濃度在血液樣本中非常低，進行病毒純化往往需要較大的樣本體積進行濃度梯度離心法，非常耗時，且無法分辨密度相當的物質。利用抗體的專一性結合REP，本研究提出三步驟改善純化病毒的過程。第一步：利用微珠式免疫反應抓取病毒；第二步：利用REP分堆粒子；第三步：透過分離液滴取得純化後的樣本。本研究分別以模擬的方式探討各步驟的可行性。
實驗結果顯示第一步驟可以奈米金模擬病毒構造證實抓取病毒的能力。改用B型肝炎病毒以及腸病毒71型也可以在第一步驟中被粒子抓取，但效率會受到類病毒粒子與抗原的干擾。第二步驟中以分選大小粒子模擬抓取病毒之粒子與雜質之間的分離。雖然無法藉由調整頻率達成目標，但以移動雷射增加粒子被聚集的速度差是可行的。實驗也確定可以REP將粒子搜集至液滴的一側，並且分離效率可達93% 。第三步驟則可透過表面修飾鐵氟龍形成親疏水介面的方法，達成液滴一分為二的分離。此研究驗證此三步驟用於純化樣本的潛力，未來可將三步驟結合並完成純化。但純化目標物轉為蛋白質將會是較佳的應用層面，且據文獻亦可配合偵測濃度的功能。另外，尚未有文獻指出粒子分堆可藉由不同粒子受反應的速度不同而達成，此新發現在未來將可作為REP深入探討的項目。

Recently, bio-detection techniques are developed to carry out the concept of Lab-on-a-chip (LOC) for time saving and sample reduction. Particle manipulation techniques are useful to bead-based applications. Rapid electrokinetic patterning (REP) is an optoelectrokinetic tool for particle manipulation. REP features low laser power, addressable manipulation, and free of complicated fabrication. As a result, we conducted virus purification based on REP to prove its capability in the field of LOC.
In virology, virus purification is necessary because the virus concentration in the blood samples is extremely low. Therefore, large sample volume is required in some purification methods, such as the density-gradient centrifugation. However, it is time consuming and it cannot separate substance with similar density. Combining the bead-based immunoreaction with REP system to achieve the virus concentration. The study was separated and evaluated in three steps. First step: capture virus by bead-based immunoreaction; second step: sort particles by REP; third step: extract the concentrated sample by droplet separation. This study investigated the feasibility of each step separately in a simulated manner.
The results showed the first step, the capability of the virus capturing is evaluated by virus-mimicking gold nanoparticles (AuNPs). The same capability is confirmed when using Hepatitis B (HBV) and Enterovirus 71 (EV71) samples, but the efficiency was interfered by virus-like-particles (VLPs) and antigens. Different sizes of particles is mixed to simulate the virus captured particles sorting from the other components in a sample in the second step. Sorting particles into two sides cannot be reached by applying different electric frequency, but it can be achieved by moving the laser spot to increase the difference of particle assembly speed. From the experiment, the particles can be concentrated on one side of the droplet by REP manipulation and the separated efficiency reached 93%. In the third step, making hydrophilic and hydrophobic regions can be used in separating a droplet into two individual ones. This study proved the feasibility of three steps process in biomedical application, but according to previous research converting the purpose to protein simultaneous purification with detection would be a better strategy. Furthermore, sorting particle by unequal response speed of different sizes of particles has never been proposed, it can be an issue of the further research on REP.

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