表面修飾金與金奈米粒子之新穎記憶體與生物元件

Abstract

跨足生物、化學和電子不同領域的研究越來越重要，結合這些技術，各式各樣用來監控或偵測表面鍵結的生物分子晶片與感測器都越發蓬勃的發展。本論文係以奈米的技術與材料應用在現今的電子及生物領域，期望能夠讓不同領域的結合迸出火花。本論文分成三部份，我們將其內容摘要說明如後。 第一部分我們提出兩種不同的方法用以量測DNA雜交時的電性，並提出奈米粒子可扮演電子的跳躍點在雜交的DNA裡面增幅其電導，單股的DNA卻無此種電導增幅的效應，然而雜交DNA伴隨10nm的金奈米粒子，可以發現高達30倍的電導增幅。另一種酫標的DNA量測法，由於銀離子轉換成銀奈米粒子的還原反應，可以在70nm的金屬間隙中增幅間係的電導達106。 此外，我們也提出70nm的金屬間隙加上單層的奈米金粒子當成DNA感測器，由於之前提出奈米粒子可扮演電子的跳躍點在雜交的DNA裡面增幅其電導，因此不同濃度的固定和目標DNA用以最佳化DNA雜交反應感測器，在1nM固定DNA的濃度條件下，此感測器能分析目標DNA達非常低的1fM，此外藉由調整變性溫度，甚至可鑑別單核酸變異的差別。 本論文第二部分，我們合成二種不同尺寸但卻相當均勻的金奈米粒子，並提出新穎的方式利用化學自組裝來製造金奈米粒子嵌入的電容結構，建立金奈米粒子常溫的製程與均勻的尺寸分布並與以分析。這些電子元件擁有低的漏電流、無金屬擴散、較大的記憶窗口、較佳的持續時間和符合F-N 穿隧的模型，此種奈米粒子組裝製程方法簡單且多變化，可以用於未來記憶體元件的製造。 最後，我們自組裝lipase(一種酶)在金的修飾表面上，金底下則是預先製造的PN二極體，此外PDMS製成流體的通道與反應槽。由於PDMS反應槽是透明的，特定波長就可以用來偵測轉酯化反應(由lipase催化)，生質柴油的產生就可以由穿透度(T%)來監控，穿透度可用來當作轉酯化反應的轉化效率指標，最後，我們利用催化酶固定化於金膜於PN二極體上，並設計微流道做為一即時可藉由穿透度偵測轉酯化的微型反應槽與感測晶片。

The interdisciplinary study of biology, chemistry, and electronics becomes more and more important. Combining the biotechnology and semiconductor technology, various types of biochips and biosensors have now been developed to detect and monitor the specific binding of biomolecules on the solid-state substrates. In this thesis, nano-technology and nano-materials are applied to the electronic and biology fields. This thesis is divided into three sections, and is described below briefly. In the first section, we report two different methods to electrically sense deoxyribonucleic acid (DNA) hybridization and suggest that nanoparticles can act as hopping sites that amplify the conductance of the hybridized DNA strand. Single-stranded DNA has no amplification effect on conductance, but hybridized double-stranded DNA tethered to 10 nm gold nanoparticles exhibits a 30-fold amplification of conductance. As to the aldehyde-derived target DNA method, silver nanoparticles from silver ion reduction in the 70 nm nanogap enhance the conductance signal by 106. In further work, the monolayer of gold nanoparticles within 72 nm gap has been proposed to function as a DNA sensor. It suggests that the nanoparticles in the nanogap could act as hopping sites which amplify the conductance of hybridized DNA strands. The conductance amplification between single strand and hybridized DNAs through gold nanoparticles is observed. Various concentrations of capture and target DNA are discussed for optimal hybridization sensing purpose. With the help of 1 nM capture DNAs, this sensor is able to analyze target DNA sequences at very low concentration of 1 fM. Furthermore, by means of adjusting the denature temperature to 60 °C, even single mismatch hybridization could be discriminated. In the second section, we synthesize two different sizes of gold nanoparticles (NPs) with uniform size distribution. A novel technique of fabricating gold NPs embedded capacitor devices utilizing chemical self-assembled gold NPs has been developed. Room temperature process and uniform size distribution of gold NPs device are built and characterized. These electronic devices have lower leakage current, no metal diffusion problem, larger memory window, better charge retention time and following Fowler–Nordheim tunneling model. This method enables the possibility of future memory applications to fabricate devices with this simple and versatile technique based on the NPs assembly. Finally, we self-assemble lipase on the gold film through surface modifications. Under the gold film, a PN photodetector was pre-fabricated. And polydimethylsiloxane (PDMS) was used as a fluid channel and reaction chamber of transesterification process. Since PDMS reactor is optically transmittance, a specific wavelength light can be used to detect transesterification reaction. The monitor for biodiesel production can be detected by means of transmittance (T %) taken as an indicator to estimate the conversion yield of the transesterification reaction. In this study, the on-chip PN diode was used as an photo detector to detect the conversion of biodiesel. As a result, the lipase-catalyzed immobilized on the Au/PN diode and a micro-fluidic device as a transesterification reaction chamber was proposed for real-time monitoring through transmittance.