Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015, Lausanne, Switzerland.
Sci Rep. 2018 Jun 20;8(1):9390. doi: 10.1038/s41598-018-26979-0.
Atomic force microscope (AFM) based single molecule force spectroscopy (SMFS) is a valuable tool in biophysics to investigate the ligand-receptor interactions, cell adhesion and cell mechanics. However, the force spectroscopy data analysis needs to be done carefully to extract the required quantitative parameters correctly. Especially the large number of molecules, commonly involved in complex networks formation; leads to very complicated force spectroscopy curves. One therefore, generally characterizes the total dissipated energy over a whole pulling cycle, as it is difficult to decompose the complex force curves into individual single molecule events. However, calculating the energy dissipation directly from the transformed force spectroscopy curves can lead to a significant over-estimation of the dissipated energy during a pulling experiment. The over-estimation of dissipated energy arises from the finite stiffness of the cantilever used for AFM based SMFS. Although this error can be significant, it is generally not compensated for. This can lead to significant misinterpretation of the energy dissipation (up to the order of 30%). In this paper, we show how in complex SMFS the excess dissipated energy caused by the stiffness of the cantilever can be identified and corrected using a high throughput algorithm. This algorithm is then applied to experimental results from molecular networks and cell-adhesion measurements to quantify the improvement in the estimation of the total energy dissipation.
原子力显微镜（AFM）基于单分子力谱学（SMFS）是生物物理学中研究配体-受体相互作用、细胞黏附和细胞力学的一种有价值的工具。然而，力谱数据分析需要仔细进行，以正确提取所需的定量参数。特别是大量分子，通常涉及复杂网络的形成；导致非常复杂的力谱曲线。因此，人们通常将整个牵引周期内的总耗散能量作为特征，因为将复杂的力曲线分解为单个单分子事件非常困难。然而，直接从转换后的力谱曲线计算能量耗散会导致在牵引实验中对耗散能量的显著高估。耗散能量的高估源于用于基于 AFM 的 SMFS 的悬臂梁的有限刚度。尽管这种误差可能很大，但通常不会进行补偿。这可能会导致对能量耗散的严重误解（高达 30%）。在本文中，我们展示了在复杂的 SMFS 中，如何使用高通量算法识别和校正由悬臂梁刚度引起的多余耗散能量。然后将该算法应用于分子网络和细胞黏附测量的实验结果，以量化对总能量耗散估计的改进。
