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標題: | 研究在金基板上沉積胺基自組裝單層分子的光氧化作用 Photo-Oxidation of Amine-Terminated Self-Assembled Monolayers on Gold |
作者: | Szu-Hsian Lee 李思賢 |
指導教授: | 薛景中 |
關鍵字: | 自組裝單層分子,衰退,光氧化作用,等電位點,藥物傳遞, SAMs,degradation,photooxidation,isoelectric point,drug delivery, |
出版年 : | 2010 |
學位: | 碩士 |
摘要: | 在金基材上沉積具有硫醇 (thiol)及長碳鏈自組裝單層分子 (Self-Assembled Monolayers, SAMs),已經被廣泛的利用在固定及偵測各類型生醫分子,包括DNA和蛋白質等。然而這些分子通常都藉由共價鍵鍵結於金基材上,所以硫醇自組裝單層分子可以穩固的貼附在金基板表面。利用不同尾端官能基分子,可以選擇特定的表面電荷;因此在給定的情況下,自組裝單層分子可藉由靜電力的交互作用應用於固定及選擇性吸脫附各種分子材料。而以現今的材料來說,胺基自組裝單層分子已經普遍的被應用在固定及偵測各式分子上。根據本團隊之前的研究,利用混合不同比例之特定官能基,自組裝單層分子可以控制固體基材表面電荷,並成功調配一系列等電位點 (Isoelectric points, IEP)。於金基板上,利用帶有-COOH和-NH2官能基的自組裝單層分子,可調配出範圍由3.5到6.5的IEP值。除了IEP,由帶有不同官能基的自組裝單層分子亦可以微調金屬電極的功函數值 (work function),受表面官能基與另一端分子形成偶極 (dipole)所影響,亦可在金基板上調配出一系列的功函數值從3.3eV到3.9eV。然而,對這種自組裝單層分子材料的穩定度並不完全了解,在本論文中,由界面電位的測量得知胺基自組裝單層分子在大氣下會隨著存放時間長短使得等電位點有衰退的現象發生;此一現象顯示表面之胺官能基,並不能穩定的存放在大氣下 (常態溫度與壓力下)。本論文透過兩種保存方法去抑制胺官能基之衰退;將胺基自組裝單層分子與光或氧氣隔離,可抑制住尾端胺基的氧化反應,且保留原來的表面特性。換句話說即是延長在金基板上的胺官能基之壽命。 Alkanethiol anchored self-assembled monolayers (SAMs) on gold are widely used to immobilize and detect molecules including DNA and proteins. Most of these molecules are covalently bonded with the SAM on the Au surface and cannot be released easily. Amine-terminated self-assembled monolayers (SAMs) on Au surfaces are commonly used to immobilize and detect various types of molecules. By using different functional groups, the interfacial charge of SAMs can be selected, and thus, they can be considered as adaptors for immobilizing and releasing materials selectively through electrostatic interaction under given conditions. In previous work, as an additional factor to control the surface charge, SAMs with mixed functional groups are presented, and it is demonstrated that the isoelectric point (IEP) can be tailored by the ratio of functional groups. Using carboxylic acid- and amine-SAM on gold substrates as an example, isoelectric points (IEPs) from 3.5 to 6.5 can be obtained arbitrarily. Furthermore, using different functional groups can make series of suface functional groups and head groups forming dipoles, it can modify work function from 3.3 eV to 3.9eV on metal electrode. However, little is known about the stability of these types of surfaces. In this work, it was observed that the surface potential (as well as the isoelectric point) of amine-bearing SAMs on flat gold substrates changed significantly with time, indicating that the surface functional group is not stable to storage under ambient conditions (standard temperature and pressure). Two methods for retarding the oxidation of the amine functional group are presented in this work. By isolating the SAM from either light or oxygen, the oxidation is suppressed and the surface properties are preserved. In other words, the shelf life of the amine-modified gold substrates is prolonged. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/46159 |
全文授權: | 有償授權 |
顯示於系所單位: | 材料科學與工程學系 |
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