烷基硫醇分子自組裝於微懸臂梁之金表面:吸附分析與撓曲量測

Alkanethiols on Gold-coated Micro-cantilever:Absorption Characterization and Deflection Measurement

張子軒(Tzu-Hsuan Chang)

指導教授 ： 陳俊杉

共同指導教授 ： 黃榮山

國立臺灣大學/工學院/土木工程學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.10353

摘要

自從80年代微機電產業蓬勃發展，人類開始利用微小尺寸的機械裝置當作感測器探索微米甚至是奈米尺度的世界。其中微懸臂梁式生物感測器可將各式各樣的物理以及化學反應轉換為力學上撓曲行為，有著高靈敏度以及容易偵測等優點成為生化研究領域的利器。
本研究以微懸臂梁式感測器搭配光學偵測平台，量測自組裝分子(self-assembled monolayers, SAMs )吸附於金表面所造成的表面應力，並且設計了可任意切換氣體以及液體的推進系統，可用於測試當實驗的環境發生改變時對自組裝分子所造成的表面應力的影響，歸納出當環境中存在著極性分子，會和自組裝分子本身的極性互相影響，改變微懸臂梁原本應有的變化表現。同時，本研究也測試了不同自組裝分子溶液的濃度吸附於金表面造成的撓曲，發現當自組裝分子溶液濃度越高時，所造成的變面應力會越大。此外，進行了在酒精溶液中不同碳鏈長的自組裝分子吸附在金表面的實驗，觀察到碳鏈越短在酒精中會造成金膜產生越大的向上表面應力。
完成自組裝分子吸附實驗之微懸臂梁晶片將搭配表面科學分析的驗證以及討論。利用X光繞射能譜(X-Ray Diffraction, XRD)可以觀測金表面的晶格面，本研究發現當自組裝分子吸附在金表面時，會使X光繞射能譜的訊號改變；而藉由X光光電子能譜(X-ray Photoelectron Spectroscopy, XPS)觀測到金硫的鍵結，可以確認撓曲訊號是由自組裝分子吸附作用所造成而非雜訊干擾。最後，提出與本研究相關的儀器與實驗設計上的改進，作為自組裝分子量測平台未來發展的參考。

關鍵字

生物感測 ； 微懸臂梁 ； 自組裝分子 ； 表面應力 ； 表面科學分析

並列摘要

The microcantilever sensor is one of the most promising platforms for the next-generation label-free biosensing applications. It outperforms other conventional label-free detection methods in terms of portability and parallelization.
The objective of this thesis is to investigate the coupling between self-assembled monolayers (SAMs) interactions and microcantilever responses. To this end, a dual compact optical microcantilever sensing platform was built to ease conducting biosensing experiments in gas-phase environments or in solutions. The thermal bimorph effect was used and found to be an effective nanomanipulator for the microcantilever platform calibration.
The study of the alkanethiol SAM chain length effect revealed that the 1-octanethiol (C8H17SH) induced larger deflection than that from 1-dodecanethiol (C12H25SH) and 1-tetradecanethiol (C14H29SH) in solutions. We also observed that higher concentration of SAMs in solutions led to higher surface stresses. In comparing with absorption experiments conducted in air and in solutions, we observed significant change of surface stresses.
In surface characterization part, by using the XRD (X-Ray Diffraction) analysis, we found that the gold surface was dominated by the (111) crystalline plane. With the XPS (X-ray Photoelectron Spectroscopy) analysis, we confirmed that the Au-S covalent bonds were occurred in SAM absorption.

並列關鍵字

biosensing ； microcantilever ； self-assembled monolayers ； surface stress ； surface characterization

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