A Novel Microarray Scanner Based on Evanescent Wave Excitation

• Main Authors: Yi-Chun Chen, 陳怡君
• Other Authors: 莊曜宇
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/73319289528204672036

碩士 === 國立臺灣大學 === 電機工程學研究所 === 95 === 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.