Diffusion in biofilms

Diffusion in biofilms can be summarized by the following four points. (i) Diffusion is the predominant solute transport process within cell clusters. (ii) The time scale for diffusive equilibration of a nonreacting solute will range from a fraction of a second to tens of minutes in most biofilm systems. (iii) Diffusion limitation readily leads to gradients in the concentration of reacting solutes and hence to gradients in physiology. (iv) Water channels can carry solutes into or out of the depths of a biofilm, but they do not guarantee access to the interior of cell clusters.