基于磁球技术对单个DNA分子的体积放大检测

Detection of Single DNA Molecule with Magnetic Microsphere Probe Based on Volume Amplification

该文提出了一种简单的基于体积放大技术的DNA单分子检测方法。利用杂交反应,采用直径约6μm磁球对DNA分子进行单分子标记后,通过对磁球的计数,可实现对单个DNA分子的定量检测。该方法采用常规显微镜配合常用的电荷耦合器（CCD,也可用目视）即可实现对单个DNA分子的计数。方法用于炭疽热DNA的单分子定量检测,其线性范围为5×10-16~1×10-14mol/L。该方法简单方便,且具有高的灵敏度和较好的适用性,为极低浓度生物分子的定量研究提供了新途径。

In this paper,a novel method to detect single DNA molecule was proposed. A sandwichtype hybridization assay was performed on a streptavidin-coated substrate. A large number of biotinylated capture DNAs（ c-DNAs） were first covalently bound to the substrate through the interaction between streptavidin and biotin. Then,the complementary target DNAs（ t-DNAs） were hybridized with the c-DNAs attached to the substrate,followed by hybridization between t-DNAs and biotinylated first probe DNAs（ p-DNAs） conjugated to streptavidin-coated magnetic microparticles（ MMPs）. In this case,one t-DNA binding one MMP could be observed with an optical microscope. The number of the MMPs is linearly proportional to concentration of t-DNA in the range of 5 × 10-16-1 × 10-14 mol / L.This size amplification method was simple and could be applied in other biomolecules.