Lyubchenko Y L, Oden P I, Lampner D, Lindsay S M, Dunker K A
Department of Physics, Arizona State University, Tempe 85287.
Nucleic Acids Res. 1993 Mar 11;21(5):1117-23. doi: 10.1093/nar/21.5.1117.
We have developed a chemical treatment for the mica surface which allows biopolymers to be held in place for atomic force microscopy, even under water, using conventional, untreated force sensing tips. We illustrate the procedure with images of lambda DNA and fd phage. The phage adheres well enough to permit in situ imaging of the adsorption process in water. These experiments yield a mean length for the phage of 883 +/- 72 nm. This compares with a measured length of 883 +/- 33 nm when the phage are imaged after drying following adsorption from water, showing that the effect of dehydration is quite small. Adhesion forces between the force sensing tip and the substrate and the sensing tip and the biomolecules are very different in the three media (air, water and propanol). The apparent height of the phage and the width and height of the DNA depends upon these adhesion forces quite strongly. In contrast, changing the Hookean spring force exerted by the scanning tip makes little difference. These results suggest that the chemical factors involved in adhesion can dominate atomic force images and that the composition of the scanning tip is at least as important a factor as its geometry.
我们已开发出一种用于云母表面的化学处理方法，该方法能使生物聚合物固定在原位，以便使用常规的、未经处理的力传感探针，甚至在水下进行原子力显微镜观察。我们用λ噬菌体DNA和fd噬菌体的图像来说明该过程。噬菌体附着良好，足以对水中的吸附过程进行原位成像。这些实验得出噬菌体的平均长度为883±72纳米。与之相比，从水中吸附后干燥的噬菌体成像时测得的长度为883±33纳米，这表明脱水的影响相当小。在三种介质（空气、水和丙醇）中，力传感探针与底物之间以及传感探针与生物分子之间的粘附力差异很大。噬菌体的表观高度以及DNA的宽度和高度在很大程度上取决于这些粘附力。相比之下，改变扫描探针施加的胡克弹力影响不大。这些结果表明，参与粘附的化学因素可主导原子力显微镜图像，并且扫描探针的组成至少与其几何形状一样重要。
Zotero 插件
