Biological cells are built up from different constituents of varying size and stiffness which all contribute to the cell’s mechanical properties. Despite this heterogeneity, in the analysis of experimental measurements one often assumes a strongly simplified homogeneous cell and thus a single elastic modulus is assigned to the entire cell. This ad-hoc simplification has so far mostly been used without proper justification. Here, we use computer simulations to show that indeed a mechanically heterogeneous cell can effectively be replaced by a homogeneous equivalent cell with a volume averaged elastic modulus. To demonstrate the validity of this approach, we investigate a hyperelastic cell with a heterogeneous interior under compression and in shear/channel flow mimicking atomic force and microfluidic measurements, respectively. We find that the homogeneous equivalent cell reproduces quantitatively the behavior of its heterogeneous counterpart, and that this equality is largely independent of the stiffness or spatial distribution of the heterogeneity.

生物细胞由不同尺寸和硬度的不同成分构成，这些成分都有助于细胞的机械性能。尽管存在这种异质性，但在实验测量分析中，人们通常假设一个高度简化的同质单元，因此将单个弹性模量分配给整个单元。迄今为止，这种临时简化大多是在没有适当理由的情况下使用的。在这里，我们使用计算机模拟来表明，机械异质单元确实可以有效地被具有体积平均弹性模量的均质等效单元取代。为了证明这种方法的有效性，我们研究了在压缩和剪切/通道流中具有异质内部的超弹性单元，分别模拟原子力和微流体测量。我们发现同质等效单元定量地再现了其异质对应单元的行为，并且这种等式在很大程度上独立于异质性的刚度或空间分布。