MHF size control is ultimately governed by the relative concentrations of nucleating species, finely tuned via the hydrodynamic diffusion gradient. Thus, a comparison of our method with probe sonication was carried out, using lipid films of equal end concentrations to MHF samples. With sonication, no clear relationship between lipid concentration and particle size was observed, and PDI were largely above 0.2, with each sample tested in triplicate (SI Fig. ). While this was far froman exhaustive exploration of the full capability of high energy shearing methods, it was taken as a benchmark study to highlight the advantages of MHF over sonication.