单波长荧光交叉相关光谱单分子检测系统

Fluorescence Cross-correlation Spectroscopy Using Single Wavelength Laser Excitation

基于激光共焦构型建立了一套单波长荧光交叉相关光谱检测系统,并对检测系统进行了优化,阐述了荧光交叉(相关)光谱基本理论.以荧光量子点和有机染料为标记探针,以人免疫球蛋白与羊抗人免疫球蛋白的结合反应为研究对象,利用该系统成功地实现了在单分子水平上对免疫结合产物的分子数、浓度、特征扩散时间和动力学半径等参数的表征.

The basic principle of fluorescence cross-correlation spectroscopy were introduced in this article. A setup of fluorescence cross-correlation spectroscopy（FCCS） was established with single wavelength laser. After the optimization of the setup, the detection volume is about 0. 7 fL. This home-built setup was successfully applied for study of the binding reaction of human immunoglobulin G with goat anti-human immunoglobulin G. With quantum dots（745 nm） and Rhodamine B（580 nm） as probes and 532 nm laser beam as excitation source, the cross-talk effect was near completely suppressed. The molecule numbers in a highly focused volume, concentration, diffusion time and hydrodynamic radius of the reaction product can be determined by FCCS system.