A Novel Microarray Scanner Based on Evanescent Wave Excitation
Date Issued
2007
Date
2007
Author(s)
Chen, Yi-Chun
DOI
zh-TW
Abstract
在偵測基因微陣列晶片的系統中，如何能快速、大面積偵測，並同時避免背景光的影響是發展微陣列晶片偵測最重要的課題，在此研究中我們建構一新的光學激發及讀取系統，可以大面積並且靈敏的檢測在玻璃玻片上微陣列之螢光訊號。
我們使用白光光源為激發光源，因為白光光源為一廣波段的光源，配合不同波段的濾鏡就可以使用不同波段的光源，不但方便且濾鏡價格也比更換雷射光源低得多。以線型光纖導光器將白光光源導成線型輸出，利用光纖耦合法將此線型光源導入玻璃片內，利用玻璃與空氣介面之全反射作用在玻璃表面上產生均勻大面積的平面光學消逝波，以此平面光學消逝波作為激發源，激發在玻璃片上的DNA微陣列，經過透鏡、濾光片，以CCD讀取此微陣列螢光訊號。由於此系統利用平面光學消逝波為激發源，可避免一般以CCD作為偵測系統時，因激發光造成的背景雜訊。我們用程式控制移動平台、CCD及照片接合，達成自動化且快速的讀取整個DNA微陣列晶片。
我們比較使用此系統與市售儀器所得之DNA微陣列晶片影像，影像皆相符且可清楚分辨螢光強度差異。一般在玻璃等透明基材上的DNA微陣列可由此系統快速、靈敏的讀出，我們並將此系統應用於非螢光的偵測，例如以奈米金粒子取代螢光物質做為訊號來源的晶片或是細胞晶片等。
In this thesis, we present a high throughtput microarray reading system for detecting fluorescent signals on a glass slide. Moreover, cost of our microarray reader is much lower than that of commercial instruments due to its simple design.
Different from conventional laser scanning microarray readers, we used a white light (metal halide) as the excitation light source. It provided large-area illumination and flexibility of changing excitation wavelengths by using various optical filters. The white light was coupled into a glass chip by using a fiber optic dual lines light guide. As the light propagated in the glass waveguide, total internal reflection at the glass-air interface produced evanescent planar waves (EPW). The EPW excited fluorescence dyes in the close proximity of the chip surface. The fluorescence signals were then taken by an objective lens and a charge coupled device (CCD). We developed a Visual Basic program to take a set of fluorescent images at different positions. The whole image of the DNA microarray was obtained by image combination.
The reader has a spatial resolution of about 3.5um. The test of Cy3 fluorescence showed concentration below 10pM can be imaged within 10 seconds. However, the background of this system was larger than that of the confocal laser scanning method. It may be due to fluorescence of the glass and scattering of surface defects. Because of the novel EPW excitation design, our system is also useful for DNA microarrays labeled with gold nanoparticles and label-free cell arrays.
Subjects
生物晶片
光學消逝波
Microarray
Evanescent Wave
Type
thesis
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