Diffusive lensing as a mechanism of intracellular transport and compartmentalization
While inhomogeneous viscosity has been identified as a ubiquitous feature of the cellular interior, its implications for particle mobility and concentration at different length scales have remained unexplored. In this work, we use agent-based simulations of diffusion to investigate how diverse manifestations of heterogenous viscosity affect movement and concentration of diffusing particles. We propose that a mode of membraneless compartmentalization arising from the convergence of diffusive trajectories into viscous sinks, which we call “diffusive lensing,” can occur in a wide parameter space and is thus likely to be ubiquitous in living systems. Our work highlights the phenomenon of diffusive lensing as a potentially key driver of mesoscale dynamics in the cytoplasm, with possible far-reaching implications for biochemical processes.
Statement of Significance
In this work we show theoretically and numerically that the inhomogeneous diffusivity known to be a ubiquitous feature of the subcellular environment can lead to the accumulation and depletion of particle concentration in viscous and fluid zones, respectively. The resulting organizing principle, called “diffusive lensing,” requires neither membranes nor phase separation, and may have fundamental relevance to transport processes across a wide range of cellular environments.