Comparison Between Shear Force and Tapping Mode AFM - High Resolution Imaging of DNA
Comparison Between Shear Force and Tapping Mode AFM - High Resolution Imaging of DNA
复制标题
剪切力与轻敲模式 AFM 的比较 - DNA 高分辨率成像
DOI：
--
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Miles
中科院分区：
文献类型：
--
作者：
M. Antognozzi;M. Szczelkun;A. Round;M. Miles
提出了一种改进的剪切力显微镜（ShFM），该显微镜可以在样品平面上的两个正交方向上激发探针的振荡并进行定量检测。这种设置允许完全控制探针的动态行为，这是获得可重复结果所必需的。越来越多的证据证实，剪切力机制是由于限制在尖端和样品之间的水层，因此，ShFM是一种真正的非接触技术。为了证实与传统扫描探针技术相比，尖端-样品相互作用的减少，使用不同的ShFM探针在空气中测量了100多个双链DNA片段（4.3 kbp）的高度和宽度。然后将测量结果与类似数量的DNA片段的敲击模式原子力显微镜（TMAFM）进行比较。从数据的统计分析中，使用ShFM获得了一致的更高的轮廓：（1.1+/-0.2）nm而不是（0.6+/-0.1）nm，这是在空气中使用TMAFM时预期的DNA高度。当获得高分辨率的DNA图像时，剪切力技术的低相互作用力允许观察到高阶周期结构，这可能反映了DNA与云母相互作用所特有的构象方面。通过改进剪切力技术，我们已经证明了ShFM可以充分利用其重要的内在优势，如非接触相互作用，并且可以成为生物分子研究中非常有用的工具。
An improved shear force microscope (ShFM) is presented, where the oscillation of the probe can be excited and quantitatively detected in two orthogonal directions in the sample plane. This set-up allows a complete control of the dynamic behaviour of the probe that is necessary in order to obtain reproducible results. Increasing evidence has been collected confirming that the shear force mechanism is due to the water layer confined between the tip and the sample and that, therefore, ShFM is a true non-contact technique. To confirm the reduced tip-sample interaction with respect to conventional scanning probe techniques, the height and the width of more than 100 double stranded DNA fragments (4.3 kbp) were measured in air using different ShFM probes. The measurements were then compared with tapping mode atomic force microscopy (TMAFM) on a similar number of DNA fragments. From the statistical analysis of the data consistently higher profiles were obtained using ShFM: (1.1+/-0.2) nm instead of (0.6+/-0.1) nm that is the expected DNA height when using TMAFM in air. When acquiring high resolution images of DNA, the lower force of interaction of the shear force technique allowed the observation of a higher order periodic structure, which may reflect a conformational aspect of DNA peculiar to its interaction with mica. By improving the shear force technique, we have shown that important intrinsic advantages, such as non-contact interaction, can be fully exploited and the ShFM can become a very useful tool in the study of biomolecules.
影响因子：
5.6
作者：
Rivetti, C;Guthold, M;Bustamante, C
通讯作者：
Bustamante, C