The height of biomolecules measured with the atomic force microscope depends on electrostatic interactions
The height of biomolecules measured with the atomic force microscope depends on electrostatic interactions
复制标题
DOI：
10.1016/s0006-3495(97)78195-5
复制
发表时间：
1997-09-01
影响因子：
3.4
通讯作者：
Engel, A
中科院分区：
文献类型：
--
作者：
Muller, DJ;Engel, A
在原子力显微镜的生物学应用中，生物样品及其载体的不同表面特性变得明显。因此，观察到的生物分子与其支撑表面之间的高度差异不仅是结构起源，而且取决于不同的样品尖端和支撑尖端相互作用。这可能导致对测量高度的负或正贡献，DLVO （Derjaguin, Landau, Verwey, Overbeek）理论描述了这种影响。实验验证表明，针尖与样品之间的静电相互作用对所得结果有很大影响。为了克服这个问题，必须调整缓冲溶液的pH值和电解质浓度，以屏蔽静电力。在这些条件下，尖端直接接触到支撑和生物系统的表面，即使是在防止样品变形所需的低力的情况下。在这种情况下，测量的高度可以与天然生物结构的厚度有关。观察到的高度依赖于电解质浓度的大分子使得估计表面电荷密度成为可能。
In biological applications of atomic force microscopy, the different surface properties of the biological sample and its support become apparent. Observed height differences between the biomolecule and its supporting surface are thus not only of structural origin, but also depend on the different sample-tip and support-tip interactions. This can result in negative or positive contributions to the measured height, effects that are described by the DLVO (Derjaguin, Landau, Verwey, Overbeek) theory. Experimental verification shows that the electrostatic interactions between tip and sample can strongly influence the result obtained. To overcome this problem, pH and electrolyte concentration of the buffer solution have to be adjusted to screen out electrostatic forces. Under these conditions, the tip comes into direct contact with the surface of support and biological system, even when low forces required to prevent sample deformation are applied. In this case, the measured height can be related to the thickness of the native biological structure. The observed height dependence of the macromolecules on electrolyte concentration makes it possible to estimate surface charge densities.