Hards Andrew, Zhou Chunqing, Seitz Markus, Bräuchle Christoph, Zumbusch Andreas
Department Chemie und Biochemie, Center for Nanoscience (CeNS), Ludwig-Maximilians Universität München, Butenandtstr. 11, 81377 München, Germany.
Chemphyschem. 2005 Mar;6(3):534-40. doi: 10.1002/cphc.200400515.
We report combined atomic force and far-field fluorescence microscopic experiments which allow the simultaneous atomic force manipulation and optical observation of individual dye-labeled DNA molecules. A detailed understanding of the binding properties of DNA to different transparent surfaces is prerequisite for these investigations. Atomic force spectroscopy and fluorescence microscopy of single DNA strands yielded detailed insight into two different types of DNA binding onto transparent polylysine-coated and silanized glass surfaces. We subsequently demonstrate how the different binding can be exploited to perform two types of nanomanipulation experiments: On polylysine, strong electrostatic interactions over the whole length of the DNA strand enable the writing of micrometer-sized patterns. By contrast, the strong pointwise attachment of DNA to silanized surfaces allows horizontal stretching of single DNA strands to lengths exceeding 1.6 times the contour length of the DNA strand. With this new approach it is possible to directly observe the rupture of the strongly bonded DNA strand.
我们报告了结合原子力和远场荧光显微镜的实验，这些实验允许对单个染料标记的DNA分子进行同时的原子力操纵和光学观察。对DNA与不同透明表面的结合特性的详细了解是这些研究的先决条件。单链DNA的原子力光谱和荧光显微镜提供了对两种不同类型的DNA结合到透明聚赖氨酸涂层和硅烷化玻璃表面的详细见解。我们随后展示了如何利用不同的结合来进行两种类型的纳米操纵实验：在聚赖氨酸上，DNA链全长上的强静电相互作用能够书写微米尺寸的图案。相比之下，DNA与硅烷化表面的强点状附着允许将单链DNA水平拉伸至超过DNA链轮廓长度1.6倍的长度。通过这种新方法，可以直接观察到强结合的DNA链的断裂。
