The internal and external mechanical environment plays an important role in tumorogenesis. As a proxy of an avascular early state tumor, we use multicellular spheroids, a composite material made of cells, extracellular matrix and permeating fluid. We characterize its effective rheology at the timescale of minutes to hours by compressing the aggregates with osmotic shocks and modeling the experimental results with an active poroelastic material that reproduces the stress and strain distributions in the aggregate. The model also predicts how the emergent bulk modulus of the aggregate as well as the hydraulic diffusion of the percolating interstitial fluid are modified by the preexisting active stress within the aggregate. We further show that the value of these two phenomenological parameters can be rationalized by considering that, in our experimental context, the cells are effectively impermeable and incompressible inclusions nested in a compressible and permeable matrix.

内部和外部机械环境在肿瘤发生中起重要作用。作为无血管早期状态肿瘤的替代物，我们使用多细胞球体，一种由细胞，细胞外基质和渗透液组成的复合材料。我们通过在几分钟到几小时的时间内通过渗透压压缩骨料并用能重现骨料中应力和应变分布的活性多孔弹性材料对实验结果进行建模，来表征其有效流变性。该模型还预测了集料中的预先存在的活动应力如何改变集料的出现的体积模量以及渗透性间隙液的水力扩散。我们进一步表明，可以通过考虑以下因素来合理化这两个现象学参数的值：