循環腫瘤細胞近年來被視為一種有用的生物標記物用以作為癌症的早期偵測，預後以及療效之偵測指標。但是現存的循環腫瘤細胞偵測方法例如免疫螢光色或逆轉錄聚合酶鏈式反應仍然相對的耗時與仰賴專業判讀。在此研究中，我們發展一套整合型微流體平台結合場效應電晶體與細胞收集結構，以達到自動化與高敏感度的循環腫瘤細胞偵測。利用這項成就，可以以對循環腫瘤細胞自動化的進行自血液中的分離，流體力學捕捉，計數與回收。此整合型微流體晶片包含有14組的細胞捕捉微流道 (20 μm×60 μm)並各自配有一個嵌入底板中的場效應電晶體生物感測器。當捕捉到的細胞數量增加時，相對於未捕捉細胞時為基準的電流訊號增益也隨之增加。因此，我們能夠透過量測電流增益的改變達到細胞計數。更重要為，此系統之電訊號能夠區分適體目標細胞與非目標細胞的電流增益差異。總結以上，此微流體系統整合場效應電晶體能夠自動化的抓取並偵測細胞，這使得它能夠應用成為血液循環腫瘤細胞偵測之工具。

Circulating tumor cells (CTCs) have been considered as a useful biomarker for early diagnosis of cancer and prognosis monitoring of cancer treatment. Furthermore, CTCs may make promising clinical impacts on the rising requirement of personalized medicine. However, the existing methods for CTC detection such as immunofluorescence methods or reverse transcription-polymerase chain reaction (RT-PCR) approaches are still relatively time-consuming and labor-intensive. In this work, we therefore developed an automatic microfluidic platform integrated with field-effect transistors (FET) and cell-trapping chambers for achieving sensitive and automatic detection of CTCs. The integrated microfluidic chip contained fourteen independent units for cell trapping and FET sensing, which was composed of a cell trapping chamber (20 μm×60 μm) and a FET biosensor embedded on the epoxy substrate. For the FET signal detection, the current gain was measured successfully, showing an increasing trend with the increasing number of cancer cells captured. It indicates that enumeration of simulated CTCs in blood samples could be achieved in accordance with the signals measured on the FET devices. More importantly, the developed system could distinguish signal difference between target cells and non-target cells. We therefore demonstrated an integrated microfluidic system equipped with FET devices which could automatically capture and detect simulated CTCs. It may be a useful tool for personalized medicine and early cancer diagnosis.

Chapter 1 Introduction 1
1.1 Circulating tumor cells 1
1.2 Biomarker and aptamer 4
1.3 MEMS in biological applications 6
1.3.1 Microfluidic system 6
1.3.2 Hydrodynamic particle trapping in microfluidic devices 7
1.3.3 Field-effect transistor 10
1.4 Motivation and novelty 12
Chapter 2 Theory 18
Chapter 3 Materials and methods 25
3.1 Design of integrated microfluidic chip 25
3.2 Fabrication of CTC trapping microfluidic chip 28
3.2.1 Lithography process 28
3.2.2 Fabrication of FET array embedded on epoxy substrates 30
3.2.3 PDMS casting and chip assembly 31
3.4 Preparation of materials 34
3.4.1 Preparation of cancer cell line HCT-8 34
3.4.2 Preparation of HCT-8-specific aptamer conjugated on magnetic beads 34
3.4.3 Preparation of HCT-8-specific aptamer conjugated on gold surfaces 36
3.5 Numerical simulation 37
3.6 Experimental procedure 39
Chapter 4 Results and discussion 51
4.1 Cells captured by magnetic beads 51
4.2 Numerical simulation of hydrodynamic trapping 53
4.3 Measurement of the height of microchannels. 56
4.4 Hydrodynamic cell trapping 59
4.5 Cell detection utilizing FET sensors 62
4.6 Selectivity test of sensor signals 66
Chapter 5 Conclusions and future prospective 68
5.1 Conclusions 68
5.2 Future prospective 70
References 71

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