Cancer claims millions of human lives every year. Delayed diagnosis and inefficient prognostic tools lead to high mortality rate. Cancer biomarkers can provide molecular based information that can be used as a supplementary tool by doctors in effective prognosis after surgery or even early stage cancer detection. Our focus is to develop a microelectronic sensor that can detect cancer biomarker, which can be used by physicians to direct patients towards right prognosis. For achieving this, AlGaN/GaN High Electron Mobility Transistor (HEMT) has been used as an Immuno-FET, in which one of the common cancer biomarkers, CEA has been used as the target protein to bind with its antibody. Traditional FET-based sensors have the limitation set by electrostatic screening effect, hindering target detection in physiological salt concentration. Complicated sample pre-treatment methods are often employed prior to detection. Our sensor design can overcome this limitation by immobilizing the receptor on the in plane gate electrode and applying a short duration pulse at the gate. The capacitive type of current obtained from HEMT, can provide us useful information and can depict dynamic mode of measurement. This method of measurement, combined with the high sensitivity of AlGaN/GaN HEMT can overcome the drawbacks of traditional FETs and offer better limit of detection, sensitivity, repeatability and convenience.

Chapter 1 Introduction…………………………………………………………
4
1.1 Motivation………………………………………………………………
4
Chapter 2 Literature Review…………………………………………………..
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2.1 Cancer…………………………………………………………………..
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2.1.1 Cancer Biomarker CEA…………………………………………..
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2.2 FET based biosensors………………………………………………….
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2.2.1 AlGaN/GaN High Electron Mobility Transistors………………..
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2.3 Surface Functionalization……………………………………………..
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Chapter 3 Experimental………………………………………………………..
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3.1 HEMT Fabrication…………………………………………………….
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3.2 CEA Antibody Immobilization……………………………………….
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3.3 Sensor Measurement…………………………………………………..
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Chapter 4 Result and Discussion………………………………………………
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4.1 Antibody orientation and stability……………………………………
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4.2 Non-specific binding from background proteins…………………….
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4.3 Sensor re-use by elution of proteins…………………………………..
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4.4 Optimization of device performance………………………………….
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Chapter 5 Summary……………………………………………………………
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Reference………………………………………………………………………..
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