Nature Materials ( IF 41.2 ) Pub Date : 2020-05-25 , DOI: 10.1038/s41563-020-0684-x Johannes Rheinlaender 1, 2 , Andrea Dimitracopoulos 1 , Bernhard Wallmeyer 3 , Nils M Kronenberg 4, 5 , Kevin J Chalut 6 , Malte C Gather 4, 5 , Timo Betz 3 , Guillaume Charras 7, 8 , Kristian Franze 1
Cortical stiffness is an important cellular property that changes during migration, adhesion and growth. Previous atomic force microscopy (AFM) indentation measurements of cells cultured on deformable substrates have suggested that cells adapt their stiffness to that of their surroundings. Here we show that the force applied by AFM to a cell results in a significant deformation of the underlying substrate if this substrate is softer than the cell. This ‘soft substrate effect’ leads to an underestimation of a cell’s elastic modulus when analysing data using a standard Hertz model, as confirmed by finite element modelling and AFM measurements of calibrated polyacrylamide beads, microglial cells and fibroblasts. To account for this substrate deformation, we developed a ‘composite cell–substrate model’. Correcting for the substrate indentation revealed that cortical cell stiffness is largely independent of substrate mechanics, which has major implications for our interpretation of many physiological and pathological processes.
中文翻译:
皮质细胞刚度与底物力学无关。
皮质硬度是一种重要的细胞特性,在迁移、粘附和生长过程中会发生变化。以前对在可变形基板上培养的细胞进行的原子力显微镜 (AFM) 压痕测量表明,细胞会根据周围环境调整其刚度。在这里,我们表明,如果该基板比细胞软,则 AFM 施加到细胞上的力会导致下面的基板发生显着变形。当使用标准赫兹模型分析数据时,这种“软基质效应”会导致低估细胞的弹性模量,这一点已通过校准聚丙烯酰胺珠、小胶质细胞和成纤维细胞的有限元建模和 AFM 测量得到证实。为了解释这种基板变形,我们开发了一个“复合细胞 - 基板模型”。