Istituto di Struttura della Materia, CNR, Rome, Italy.
BMC Bioinformatics. 2018 Jul 6;19(1):258. doi: 10.1186/s12859-018-2265-4.
The collection and analysis of Atomic Force Microscopy force curves is a well-established procedure to obtain high-resolution information of non-topographic data from any kind of sample, including biological specimens. In particular, these analyses are commonly employed to study elasticity, stiffness or adhesion properties of the samples. Furthermore, the collection of several force curves over an extended area of the specimens allows reconstructing maps, called force volume maps, of the spatial distribution of the mechanical properties. Coupling these maps with the conventional high-resolution topographic reconstruction of the sample's surface, provides a deeper insight on the sample composition from the structural and nanomechanical point of view.
In this paper we present the open source software package FC_analysis that automatically analyses single force curves or entire force volume maps to yield the corresponding elasticity and deformability images. The principal characteristic of the FC_analysis is a large adaptability to the various experimental setups and to different analysis methodologies. For instance, the user can provide custom values for the detector sensitivity, scanner-z sensitivity, cantilever's elastic constant and map's acquisition modality and can choose between different analysis methodologies. Furthermore, the software allows the optimization of the fitting parameters and gives direct control on each step of the analysis procedure. Notably, to overcome a limitation common to many other analysis programs, FC_analysis can be applied to a rectangular portion of the image, allowing the analysis of inhomogeneous samples. Finally, the software allows reconstructing a Young's modulus map at different penetration depths, enabling the use of modern investigation tools such as the force tomography.
The FC_analysis software aims to become a useful tool for the analysis of force curves maps collected using custom or commercial Atomic Force Microscopes, and is especially useful in those cases for which the producer doesn't release a dedicated software.
原子力显微镜力曲线的采集和分析是一种成熟的方法，可以从任何类型的样品（包括生物标本）中获取高分辨率的非形貌数据信息。特别是，这些分析通常用于研究样品的弹性、硬度或粘附特性。此外，在样品的较大区域上采集多个力曲线，可以重建力体积图，从而对样品的机械性能的空间分布进行重构。将这些力体积图与样品表面的常规高分辨率形貌重构相结合，可以从结构和纳米力学的角度深入了解样品的组成。
本文介绍了一个开源软件包 FC_analysis，该软件可以自动分析单个力曲线或整个力体积图，以生成相应的弹性和变形图像。FC_analysis 的主要特点是对各种实验设置和不同的分析方法具有很大的适应性。例如，用户可以为探测器灵敏度、扫描器-z 灵敏度、悬臂梁的弹性常数和地图采集模式提供自定义值，并在不同的分析方法之间进行选择。此外，该软件允许优化拟合参数，并直接控制分析过程的每个步骤。值得注意的是，为了克服许多其他分析程序共有的一个局限性，FC_analysis 可以应用于图像的矩形部分，从而可以分析不均匀的样品。最后，该软件允许在不同的穿透深度下重建杨氏模量图，从而可以使用力断层扫描等现代研究工具。
FC_analysis 软件旨在成为分析使用定制或商业原子力显微镜采集的力曲线图的有用工具，特别是在生产者未发布专用软件的情况下非常有用。
