微阵列芯片的荧光光漂白特性

Fluorescence Photobleaching Properties for Microarray Chips

微阵列技术为大量基因表达水平的同时监控提供了一种高效的手段。随着微阵列芯片朝着小型化、高通量和弱信号方向发展,荧光检测技术以其易寻址和高灵敏度等优势越来越受到世人关注。在微阵列技术中,人们通过检测微阵列芯片上不同位置斑点的荧光信号强度,可以得知微阵列芯片不同位置固定的已知序列探针与荧光染料标记的cDNA样品的杂交情况。对一张微阵列芯片多次扫描后,荧光染料发生光漂白,荧光强度发生衰减变化,它将为微阵列的数据分析带来误差。使用荧光浓度梯度微阵列芯片研究了芯片经多次扫描后荧光斑点强度的衰减情况,通过拟合相同荧光斑点经多次重复扫描后得到的信号强度,得到了荧光斑点强度按指数形式衰减的规律,并在此基础上研究了荧光斑点强度衰减指数模型中的参数与荧光斑点初始浓度的关系,为进行微阵列芯片数据光漂白误差修正提供了实验依据。

Microarray technology has provided a way to quantitate the simultaneous expression of a large number of genes. As microarray developed towards miniaturization, high throughput and weak signals, it needs high sensitive and addressable detection. Fluorescent detection has been given more and more attention. The very rapid and remarkable development of fluorescence detection will no doubt impact the applications of microarray technology. In generally, fluorescence intensities of microarrays, which reflect the biochemical reaction are detected by a photomuhiplier tube or a CCD camera, resulting in the production of digital images. As microarrays are scanned repeatedly for many times, the fluorescent dye will be bleached and the relative intensities of fluorescence probes will decay, which result in the error of microarray analysis. So the mathematical modification on the values of fluorescence intensities is important during microarray processing. An research detection repeatecll experimental device based the sensitive CCD area imaging and scanning technology is designed for the on microarray fluorescence photobleaching properties, which is proved to be useful for fluorescence of microarray. The microarray consisting of different concentration fluorescence probes is scanned y in the same condition by this device, and the relative intensities of the same fluorescence probe in different images are extracted orderly by the special software, and then fitted by the nonlinear curves. The results show that the decay of the relative fluorescence intensity can be fitted perfectly by an exponential fitting method. The meanings of parameters in this exponential model are explained. The relations between the parameters of the exponential model and the concentrations of fluorescence probes are also analyzed. The analysis results can be used to modify the data error caused by the photobleaching in microarray technology and to improve the reliability of microarray analysis.