氮化鎵在DNA感測上之應用

GaN for DNA-sensing Applications

陳金珮

指導教授 ： 陳貴賢 ； 林麗瓊

國立臺灣師範大學/理學院/化學系/碩士(2004年)

摘要

氮化鎵，它是一種重要的光電材料，這是因為其為直接寬能隙(3.4eV)的半導體材料。最近它有許多在感測器上的應用，例如:
高功率場效應晶體管和微電子裝置。然而三族氮化物具有化性不活潑且生物相容性已經被大家所知道，所以這樣的特性可以運用在三族氮化物半導體為基礎的生物感測器。在本論文中，為了建構氮化鎵去氧核醣核酸感測器，我們將已經矽氧烷化之氮化鎵表面藉由雙硫鍵與末端硫化的寡核酸鍵結 。進而從接觸角的量測、原子力顯微鏡、x光光電子能譜術、共軛焦光學顯微鏡、高解析穿透式電子顯微鏡等分析技術可以確認DNA分子可以藉由共價鍵的方式固定到氮化鎵表面。由電化學阻抗的分析，可以證明DNA分子固定到氮化鎵表面並且可以辨別出單股DNA和雙股DNA之間的差異。從螢光光譜(PL)分析，可觀測到當雙股DNA鍵結到單股DNA修飾的氮化鎵表面時會有螢光熄滅的現象產生。這意味著氮化鎵同時具有電化學以及光學上DNA的感測特性，相較於氮化鎵薄膜，氮化鎵奈米線具有較高的偵測靈敏度，適於未來之生物感測之應用。

關鍵字

氮化鎵 ； 氮化鎵去氧核醣核酸感測器

並列摘要

In this report, the applicability of the III-nitride-based materials as a semiconductor-based biosensors is demonstrated. Generally, GaN is considered as potential candidate for optoelectronic material because it is a wide direct band gap (3.4 eV) semiconductor. Recently, a lot of interest has been developed on its sensor-application, e.g. high power FETs and microelectronic devices. Furthermore, group III-nitrides are known for their chemical inertness and bio-compatibility, which leads to the realization of biosensors based on III-nitrides semiconductor. In this work, GaN is used for the construction of a DNA-sensing material by immobilizing thiol-terminated oligonucleotides onto a mercaptosilane-modified GaN surface by using disulfide bonds.The covalent bond attachment of thiol-modified DNA oligomers to MPTS-modified GaN surface has proved by contact angle measurement, atomic force microscopy (AFM), X-ray photoelectron spectroscopy(XPS), confocal optical microscope(COM),and high-resolution transmission electron microscopy (HR-TEM).Using electrochemical impedance measurement, it is possible to observe the immobilized DNA molecules on the GaN surface and discriminate between ss and ds DNA. Quenching of photoluminescence signal has been observed when a ss-DNA modified GaN subjected to ds-DNA modification. This demonstrates that surface modified GaN can perform as a sensor for DNAs. Comparative to GaN this films, GaN NWs is one case have higher sensivity for DNA –sensing, which one highly desirable for bio-sensing applications.