Cell mechanics can be robustly derived from AFM indentation data using the brush model: error analysis
Cell mechanics can be robustly derived from AFM indentation data using the brush model: error analysis
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DOI：
10.1039/d2nr00041e
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发表时间：
2022-02-26
期刊：
影响因子：
6.7
通讯作者：
Sokolov，Igor
中科院分区：
文献类型：
--
作者：
Makarova，N.;Sokolov，Igor
与传统的赫兹模型相比，刷子模型被引入到解释AFM在生物细胞上收集的压痕数据中，以更一致的方式。它考虑了细胞周围的细胞刷状层（糖萼分子和微绒毛/微脊的混合物）的非赫兹变形的存在。该模型允许找到有效的杨氏模量的细胞体在一个较小的深度依赖性的方式。此外，它允许发现由于细胞周围刷层的力。与用于解释压痕实验的简单力学模型相比，刷子模型具有额外的复杂性。这引起了对细胞体和细胞周层的机械性质分离的可能的明确性的关注。在这里，我们提出的刷子模型的鲁棒性的分析，并证明了弱依赖模型和实验数据内的不确定性所获得的结果。我们批判性地分析了使用刷子模型上收集的各种AFM力曲线，而不同的细胞类型：人类宫颈上皮细胞，大鼠神经元，和斑马鱼黑色素细胞。我们的结论是刷模型是强大的，由于模型和实验数据的可能的不确定性的有效杨氏模量的定义的误差在4%以内，这是小于错误，例如，由于一个典型的不确定性的弹簧常数的AFM悬臂。我们还讨论了由于细胞周围刷层的力的参数化的错误。
The brush model was introduced to interpret AFM indentation data collected on biological cells in a more consistent way compared just to the traditional Hertz model. It takes into account the presence of non-Hertzian deformation of the pericellular brush-like layer surrounding cells (a mix of glycocalyx molecules and microvilli/microridges). The model allows finding the effective Young's modulus of the cell body in a less depth-dependent manner. In addition, it allows finding the force due to the pericellular brush layer. Compared to simple mechanical models used to interpret the indentation experiments, the brush model has additional complexity. It raises the concern about the possible unambiguity of separation of mechanical properties of the cell body and pericellular layer. Here we present the analysis of the robustness of the brush model and demonstrate a weak dependence of the obtained results on the uncertainties within the model and experimental data. We critically analyzed the use of the brush model on a variety of AFM force curves collected on rather distinct cell types: human cervical epithelial cells, rat neurons, and zebrafish melanocytes. We conclude that the brush model is robust; the errors in the definition of the effective Young's modulus due to possible uncertainties of the model and experimental data are within 4%, which is less than the error, for example, due to a typical uncertainty in the spring constant of the AFM cantilever. We also discuss the errors of parameterization of the force due to the pericellular brush layer.