Quantitatively, we assume the effective diffusion coefficient, 𝐷 𝑏𝑎𝑐 , of the dye in the presence of bacteria is dependent on the distance, 𝑧, from the exposed face and on the time, 𝑡, elapsed since the start of the digestion process (assumed to be simultaneous to the beginning of the release). This dependence on space and time is accounted for by writing 𝐷 𝑏𝑎𝑐 = 𝑤𝐷 ℎ + (1 -𝑤)𝐷 𝑐 , where 𝑤(𝑧, 𝑡) is the fraction of digested lipids at time 𝑡 and position 𝑧. The profile of 𝑤(𝑧, 𝑡) can be obtained by considering Fickian diffusion also for the digested lipids, where a boundary condition 𝑤(0, 𝑡) = 1 is imposed by assuming lipid diffusion to be much slower than digestion (see Methods for further details). Within this approach, 𝑤(𝑧, 𝑡) can be computed by knowing the diffusion coefficient 𝐷 𝑑𝑖𝑔 of the digested lipids, which we estimated to be 𝐷 𝑑𝑖𝑔 = (2.87 ± 0.14) • 10 -8 cm 2 s -1 based on the growth rate of hexagonal mesophases in thin films as measured by the polarized light microscopy (Figure , 36.1 ±1.7 µm 2 s -1 ). In Figure , we report the predicted release profile as a dashed line against the experimental data (blue squares). The excellent quantitative agreement strongly supports our microscopic model, particularly considering the absence of any fitting parameters. An insightful by-product of the calculation is provided in the inset of Figure , where we report the time evolution of the overall fraction of mesophase with hexagonal symmetry, as estimated from our model. It can be appreciated that the nanoscopic change in the structure occurs at comparable times as the release process, which is a direct consequence of the similar magnitude between 𝐷 𝑑𝑖𝑔 and 𝐷 𝑏𝑎𝑐 . As can be seen, release of encapsulated hydrophilic molecules in the presence of S. aureus is a balance between the rate of bacterial growth, lipid diffusion and consequent lipid mesophase structure. phases, and release data in the presence of bacteria (blue squares). Dotted lines are the fits obtained by tuning 𝐷 𝑐 and 𝐷 ℎ in the theoretical formula reported in the Methods. The dashed line is the prediction for the release obtained by solving the coupled diffusion problem. Note that all the parameters used to compute the dashed line were obtained via control experiments, i.e. this prediction is not the result of a fitting procedure. Shaded areas indicate the indeterminacy associated to the error of the parameters. In the inset, we plot the time evolution of the overall fraction of the inverse hexagonal structure within the mesophase in the presence of bacteria.