Speaker
Description
Transport phenomena in biological systems are essential for maintaining life sustaining functions. Notably, biological materials, including tissues and cells can be viewed as porous media. Here we will focus on the passive transport of macromolecules in the intracellular space, involved in many cellular functions such as cell migration, blebbing and apoptosis. While it is well established that intracellular crowding significantly impacts macromolecule mobility, the physical mechanisms by which cytoplasmic structures influence diffusion within the cell remain unclear.
We propose a multiscale diffusion model of the intracellular space based on the volume averaging method. The cytoplasm is treated as a hierarchical porous medium with nanometric and micrometric obstacles. Numerical solution of the model allows us to predict the effective cytoplasmic diffusion coefficient for various obstacle volume fraction. Model predictions are confronted to experimental measurements of the effective diffusion coefficient in live cells and highlight the importance of two key diffusion reduction mechanisms: tortuosity and hydrodynamic drag. Importantly, we find that the effective cytosolic diffusivity is not dependent on specific cellular region but rather on intracellular obstacle volume fraction. Additional model predictions of intracellular diffusivity as a function of the macromolecule size give excellent agreement with literature data.
Altogether, this work demonstrates the potential of porous media modeling approaches to better understand transport phenomena in heterogeneous biological systems all the way to the intracellular scale.
| References | Destrian et al., PNAS (2026) |
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| Country | France |
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