- 學位論文
I. 數位訊號處理增進直⾓角度光散射波寬精準度及開發低訊號雜訊⽐比計算分⼦子量⽅方法 II. 數位液滴介電潤濕技術結合類⽐比流體流道開發流體篩選收集裝置
I.Using Signal Processing to Improve the Accuracy of Peak Width Obtained by Right-Angle Light- Scattering and Develop a Method to Calculate the Molecular Weight at Low Signal-to-Noise Ratio II. Integrating Electrowetting on Dielectrics Device as Flow Switch with Micro-flow Cytometer
摘要
中文摘要 I. (數位訊號處理) 尺寸篩選層析儀 (Size-exclusion chromatography；簡稱SEC) 搭配光散射偵測器 (light-scattering；簡稱LS) 及折射計 (refractometer) 是一種常見於直接量測高分子聚合物的分子量技術。但由於熱擾動與其他雜訊干擾的關係，溶質及溶劑分子皆會散射雷射光，使光散射偵測器紀錄的層析圖譜基線 (baseline) 雜訊強，特別是當樣品溶液濃度低於1 mg/mL，且光散射訊號存在兩個或兩個以上的波峰訊號時，其波寬範圍就難以用肉眼鑑定，或用肉眼判斷後，分子量結果卻不盡人意。 因此希望能使用先前實驗室開發的濾波器方法，搭配旋積 (convolution) 運算的方式，設計出一種可以讓得到波寬範圍更加準確的方法，免除因為人為判斷造成的誤差，提升高分子合成鑑定上的精準度。 二次微分濾波器 (Second-derivative filter) 屬於帶通濾波器 (band-pass filter) 只能讓特定頻帶的訊號通過，在此範圍外的訊號都會被濾除。本實驗先使用軟體Matlab模擬不同解析度之訊號，在波寬範圍及訊號強度都固定的前提下，希望能利用模擬的方式了解在不同解析度狀況下，該如何進行取點判斷。 旋積運算為一種交互相關法，其運算規則中會由原始圖譜上的第M點、參考圖譜上的第N點，經運算後得到旋積圖譜上的第M+N-1點。因此希望能藉由此運算規則，簡單從旋積圖譜上的點投射回原始圖譜上找出確切的波寬範圍。 接著使用實際樣品，將直鏈高分子標準品pullulan 400 k與pullulan 5 k進行混合，驗證在實際操作時，所得到的結果是否如預期的能解決波寬不易判斷的問題。最後，將此數位訊號處理方法找到的波寬範圍使用軟體OmniSEC計算分子量，並將此結果與使用人為判斷波寬的方式計算得到的分子量進行比較。 由比較結果可以得知，使用濾波器與未使用濾波器取得波寬的分子量結果，在訊雜比較差的pullulan 5 k中，誤差的提升程度約一個數量級。在pullulan 400 k與pullulan 5 k各別的精確度中使用與未使用濾波器的結果也有明顯的差異。 另外，在光散射偵測器訊號雜訊比低於10時，軟體OmniSEC即無法進行分子量的計算，但在合成高分子的過程中，有時過程繁瑣、產率也無法控制在高濃度的情況下，仍希望能夠就少量的樣品進行分子量檢測。因此在此研究中，希望能從光散射與折射的原理，並結合第一部分開發出的數位訊號處理的方式，先找出訊號準確的波寬範圍，接著使用數值分析處理推得低訊雜比訊號的重量平均分子量 (weight-average molecular weight，Mw)。 實驗結果顯示，經由一連串的計算即能得到樣品的重量平均分子量，四組實驗的誤差皆在6%以下，且精確度也都在3%內。儘管無法與儀器OmniSEC的結果進行比較確認，但至少使用此方法能算出軟體得不到的數值，達到擴展計算高分子重量平均分子量的訊雜比範圍。 中文摘要 II. (介電潤濕整合裝置) 電潤濕 (Electrowetting on dielectrics；簡稱 EWOD) 是一種利用電動力的介電質潤濕效應。在疏水表面上，施加電壓改變表面張力梯度，將液滴數位化操控，使液滴進行產生 (generation)、傳輸 (movement)、分離 (division)、合併 (merge) 等四個動作，將這些整合於同一晶片上以進行生化反應、生醫檢測等應用的前期處理。 本實驗晶片是結合微流道與介電潤濕技術的整合型裝置。電潤濕晶片使用兩片鍍有氧化銦錫 (indium tin oxide；簡稱ITO) 導電玻璃作為晶片的上下電極，在下電極進行光微影製程製作電極圖形，塗佈介電層及疏水層；在上電極鑽一個喇叭狀的洞，使注入的液體能順利滴入晶片，並在表面及洞口塗佈疏水層；使用3層3M膠帶 (120 μm) 為兩導電玻璃間隙的高度，並使用繼電器作為控制此晶片電場切換的裝置。流道採用聚二甲基矽氧烷 (poly(dimethylsiloxane)；簡稱PDMS) 高分子為材質放置在上電極上方，最後用壓克力夾具將整體裝置穩固結合。 分別測試流道及電潤濕晶片的實用性。晶片實驗使用注射幫浦將去離子水注入流道並滴入晶片內，施加70 Vpp 的交流電壓 (1 kHz) 後，即能驅使液滴移動至收集區。當流道中注入螢光顆粒並使用光電倍增管 (photomultiplier；簡稱PMT) 搭配電壓訊號截取卡，從圖表及動態影片確認PMT可準確計數通過偵測視窗的每一個螢光顆粒。 未來會將流道與電潤濕晶片結合，使用PMT在流道中計數螢光顆粒，並觸發電潤濕晶片進行流向切換與顆粒收集。證明此半開放的整合型裝置可以直接注入液體樣品或連接其他微槽道流體的出口端，方便進行樣品篩選和後續的生化分析。
並列摘要
Abstract I. Static light-scattering (LS) detection can determine the molecular weight (Mw) of polymers eluted with size-exclusion chromatography (SEC) without using any standards when the differential refraction index (RI) of solutes are obtained. On the other hand, the noisy chromatographic signal peak acquired using a static LS detector often causes difficulty in peak-width recognition. This disadvantage limits the determination accuracy and precision of the values. This study developed one second-order derivative filtering procedure by convolving the original LS chromatogram against the second-derivative curve of one artificial Gaussian-shape chromatographic peak to suppress the noises and to correct the baseline of the chromatogram. More accurate estimations of the chromatographic peak widths of pullulan samples were achieved to improve the determination accuracy. For noisy original chromatography peaks of pullulan 5 k (SNR of approximately 10), the non-ideal determination accuracy of the values (9.3%) is improved to –1.3% with the assistance of the filtering procedures. In addition, when the signal to noise ratio of the polymer sample is lower than the calculated limitation of the built-in application software package OmniSEC 4.6 (SNR lower than 10), the weight-average molecular weight (Mw) can not be calculated. But the has occupied a very important role in the synthesis of polymers. To overcome this limitation, we consider the principles of refractometer and light-scattering detector to get the molecular weight. Using the filtering procedure we designed in part one to find the more accurate peak width, then combining the numerical calculation to calculate the molecular weight of low SNR signal. We infer that we can use the numerical calculation to get the molecular weight measured from the SEC which the SNR is lower than the limitation of the software package. This method increased the calculable SNR of the software package OmniSEC to calculate the polymers’ weight-average molecular weight. Abstract II. Electrowetting on dielectrics (EWOD) is droplet-based microfluidic technique to control the generation, division, merge, or movement of droplets via electrical signals. The mechanical parts such as pumps and valves are not in needed for electrically actuated EWOD device. In this study, the dual-planar ITO glass slides were used to fabricate EWOD chip. The standard photolithography techniques were utilized to craft the bottom planar electrode array to coat with photoresist dielectric layer. The upper ITO glass slide was drilled through and chamfered for the convenience to fill liquid droplet. In addition, the dual-planar ITO glass slides were coated with the Teflon hydrophobic layer of 300 nm in thickness. The applied electric field with voltage 70 Vpp of 1 kHz is switched by relays to trigger the electrode on the bottom slide consecutively. This design of semi-opened chip can directly receive liquid sample or connect with the micro-channel outlet of continuous flow. In the future, we want to use the photomultiplier to pick up the signals from the fluorescence particles and couple with this EWOD microchip to separate the fluorescence particles from other non- fluorescence particles.
參考文獻
延伸閱讀
- Huang, W. C. (2014). 基於低功耗動脈光容積描計法訊號調變與解調變晶片設計之可攜式生理監測系統實作 [master's thesis, National Chiao Tung University]. Airiti Library. https://doi.org/10.6842/NCTU.2014.01057
- 謝書府、施明利、杜炯榮、張家溥、吳傑堂、魏憲鴻（2007）。應用輸送現象原理實現“奈升”化學工程之新策略：結合微介觀多重尺度概念之微流控技術。化工，54(5)，3-20。https://doi.org/10.29803/CE.200710.0002
- Chan, C. H. (2021). 應用單鬆弛時間熱晶格波茲曼法及圖形顯示卡叢集計算有熱傳的壓力驅動渠道流的噴流現象 [master's thesis, National Tsing Hua University]. Airiti Library. https://www.airitilibrary.com/Article/Detail?DocID=U0016-2412202116193635
- 劉昆其（2009）。Using the Excitation Surface Plasma Waves by the Method of Optical Frustrated Total Internal Reflection to the toxic gases Measurement〔碩士論文，健行科技大學〕。華藝線上圖書館。https://doi.org/10.6824/UCH.2009.00045
- 陳冠宇（2014）。Using frustrated total internal reflection and excitation surface plasma waves methods to resonance angle of different concentrations iodine〔碩士論文，健行科技大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0022-1806201415324600