在不均勻電場下產生的交流電動力是一種非常重要的物理現象，並且非常適合對微流體系統中的微粒子和溶液進行直接操控。微流體中主導的力會根據所加交流電場的參數，如電壓和頻率；以及溶液和微粒子的特性，如導電率和介電常數而改變。 / 這篇論文將會討論在微流體芯片中利用交流電動力的三個生物醫學領域應用範例。第一個例子中，介電電泳被用來擔任集中器的作用，將溶液中DNA附著的碳納米顆粒排列在微電極之間。這種納米材料的性質以及作為傳感器應用的可能性也將被研究。第二個應用著重在微通道中對細胞的操控。試驗過程中觀察到黑色素細胞在正介電電泳力作用下的自旋現象，而不含黑色素的細胞在相同條件下鮮少發生。研究的重點包括產生這種現象的條件和可能原因，以及對細胞旋轉速度的量化和比較。在這基礎上，實驗證實了對原本不含黑色素的細胞實現人為引發自旋現象的可能性。在第三個應用中，交流電熱流被用來輔助電化學生物傳感器的RNA雜交過程從而克服封閉系統生物傳感器的一些缺點，進而實現快速病原檢測。優化后的生物傳感器序列陣列性能非常有競爭力。具體來說，傳感器特異性良好，信噪比提高，檢測限提升。另外，初步臨床樣本檢測證實這種交流電動力輔助下的生物傳感器陣列具有在將來被整合成便攜式醫療檢測儀器從而實現分子生物診斷的潛質。 / AC Electrokinetics is a very important phenomenon in the presence of non-uniform electric fields that is suited for direct manipulation of both particles and bulk fluid in the microfluidic system. Based on the parameters of the applied AC electric field such as voltage and frequency, as well as the properties of solution and the particles, for example, conductivity and permittivity, dominant forces in the microfluidic system may vary. / In this thesis, three examples of utilizing AC Electrokinetics in the microfluidic system for biomedical applications will be discussed. The first application was to use dielectrophoresis as a concentrator to form DNA attached carbon nanoparticles alignment between microelectrodes. The properties of this type of nanomaterial were investigated for further sensing applications. Then, the second example focused on cell manipulation in the microchannel, as self-rotation phenomenon of the pigment cells under positive dielectrophoretic force was observed, while there was no movement for non-pigment cells applied with the same dielectrophoresis parameters. The conditions and possible reasons for this phenomenon were investigated, the cell rotation speed was quantified and compared, based on which, manually induced rotation using non-pigment cells was proved successful. Last but not least, AC Electrothermal effect was utilized to facilitate the hybridization process of electrochemical biosensor arrays to overcome the disadvantages of enclosed sensor system and to further realize rapid pathogen identification. Optimized biosensor arrays showed promising performance including good specificity for a panel of target species, enhanced signal-to-noise ratio and improved limit-of-detection. Furthermore, preliminary clinical sample validation was conducted to confirm the feasibility of using this type of AC Electrokinetically facilitated biosensor arrays for future integration into a point-of-care device for molecular diagnostics. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Ouyang, Mengxing. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 103-110). / Abstract also in Chinese. / List of Figures --- p.ix / List of Tables --- p.xiii / List of Abbreviation --- p.xiv / Chapter I. --- Introduction to AC Electrokinetics --- p.15 / Chapter 1.1. --- AC Electrokinetics --- p.15 / Chapter 1.2. --- Dielectrophoresis --- p.16 / Chapter 1.3. --- AC Electrothermal Flow --- p.17 / Chapter 1.4. --- Advantage of Miniaturized Microfluidic Device --- p.18 / Chapter II. --- DEP Manipulation of CNPs and DNA-CNPs --- p.20 / Chapter 2.1. --- Introduction --- p.20 / Chapter 2.1.1. --- Carbon Nanoparticles and Their Applications --- p.20 / Chapter 2.1.2. --- Fluorescent CNPs and Bio-imaging --- p.21 / Chapter 2.1.3. --- DNA Attached Nanomaterials --- p.23 / Chapter 2.2. --- Preparation of CNPs --- p.24 / Chapter 2.2.1 --- Fabrication Process --- p.24 / Chapter 2.2.2 --- Fluorescence Property --- p.24 / Chapter 2.3. --- DEP Manipulation of CNPs --- p.27 / Chapter 2.3.1. --- CNPs Linkage Formation --- p.27 / Chapter 2.3.2. --- DEP Parameters --- p.28 / Chapter 2.3.3. --- Electrical Stability --- p.30 / Chapter 2.4. --- DEP Manipulation of DNA-attached CNPs --- p.32 / Chapter 2.4.1. --- Preparation of Sensor Chips --- p.32 / Chapter 2.4.2. --- Current-Voltage Characterization --- p.34 / Chapter 2.4.3. --- Stability --- p.35 / Chapter 2.4.4. --- Temperature Dependency --- p.39 / Chapter 2.4.5. --- Humidity Dependency --- p.40 / Chapter 2.5. --- Summary --- p.44 / Chapter III. --- Self-Rotation of Cells in the DEP Field --- p.45 / Chapter 3.1 --- Introduction --- p.45 / Chapter 3.2 --- Preparation of Microfluidic Chips --- p.46 / Chapter 3.2.1 --- Electrode Design --- p.46 / Chapter 3.2.2 --- Fabrication of Microfluidic Chips --- p.47 / Chapter 3.3 --- Cell Rotation Experiments --- p.49 / Chapter 3.3.1 --- Cell Behavior in the Dielectrophoretic Field --- p.49 / Chapter 3.3.2 --- Conditions to Induce Self-Rotation Phenomenon --- p.50 / Chapter 3.3.3 --- Pigment Cells Versus Non-Pigment Cells --- p.54 / Chapter 3.3.4 --- Investigation of Self-Rotation Speed of Pigment Cells --- p.55 / Chapter 3.3.5 --- Self-Rotation of Pigment Cells from Different Passages --- p.60 / Chapter 3.3.6 --- Cell Rotation Speed Calculation Using Algorithm --- p.62 / Chapter 3.3.7 --- Manually Induced Cell Rotation --- p.64 / Chapter 3.4 --- Summary --- p.67 / Chapter IV. --- AC Electrothermal Flow Facilitated Biosensors --- p.68 / Chapter 4.1 --- Introduction --- p.68 / Chapter 4.2 --- Probes and Biosensor Arrays --- p.71 / Chapter 4.2.1 --- Probe Design --- p.71 / Chapter 4.2.2 --- Specificity and Sensitivity of The Enclosed System --- p.71 / Chapter 4.2.3 --- Clinical Urine Sample --- p.73 / Chapter 4.2.4 --- Electrochemical Biosensor Arrays and Their Functionalization --- p.74 / Chapter 4.3 --- Mechanism and Experimental Methods --- p.76 / Chapter 4.3.1 --- Detection Mechanism of 16S rRNA --- p.76 / Chapter 4.3.2 --- Two-Color Fluorescence Thermometry --- p.78 / Chapter 4.3.3 --- Fluorescent Sphere Velocity Measurement --- p.79 / Chapter 4.4 --- Microscale Characterization of the Enclosed System --- p.80 / Chapter 4.4.1 --- Improvement of Washing Process --- p.80 / Chapter 4.4.2 --- Temperature Measurement --- p.80 / Chapter 4.4.3 --- Quantification of ACEK facilitated Mixing --- p.82 / Chapter 4.5 --- Optimization of ACEK Parameters --- p.84 / Chapter 4.5.1 --- Hybridization Duration --- p.84 / Chapter 4.5.2 --- Voltage --- p.85 / Chapter 4.6 --- Performance of a Panel of Target Species --- p.89 / Chapter 4.6.1 --- Limit of Detection --- p.89 / Chapter 4.6.2 --- Specificity --- p.90 / Chapter 4.7 --- Clinical Sample Validation --- p.92 / Chapter 4.8 --- Discussion --- p.94 / Chapter 4.8.1 --- Hybridization Efficiency --- p.94 / Chapter 4.8.2 --- Background Signal --- p.96 / Chapter 4.9 --- Summary --- p.97 / Chapter V. --- Conclusion --- p.98 / Chapter 5.1 --- Nanoparticles Concentration Using DEP --- p.98 / Chapter 5.2 --- Cell Manipulation in the DEP field --- p.100 / Chapter 5.3 --- AC Electrothermal Flow Facilitated Enclosed Biosensors --- p.101 / Bibliography --- p.103
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_328502 |
| Date | January 2012 |
| Contributors | Ouyang, Mengxing., Chinese University of Hong Kong Graduate School. Division of Mechanical and Automation Engineering. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | electronic resource, electronic resource, remote, 1 online resource (xiv, 15-110 leaves) : ill. (some col.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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