Scattering Simulations from Laterally Heterogeneous Lipid Vesicles

Lipid phase separation is a functional hallmark of cellular membranes and an attractive feature in lipid membrane applications. In cell membranes, lipids of different species partition into lateral heterogeneities, or domains, with contrasting structural and elastic properties. The manifestation of this phase separation on the nanoscale has remained rather elusive, with few techniques available for examination. Of these, small angle neutron scattering (SANS) has become an invaluable tool, sensing not only structural differences between the domains and matrix but also differences in lipid partitioning within emergent phases. Here, we expand on earlier scattering simulations employing circular domain morphology to more general domain configurations which have been previously observed in multicomponent lipid membranes. Combining SANS measurements with simulations, we determine the morphology and composition of lipid domains on spherical lipid vesicles composed of biological and engineered lipid species. Furthermore, we investigate how domain morphology influences the resulting scattering signals in response to compositional variations and molecular substitutions. These developed capabilities have far-reaching implications in artificial cell technologies and soft membrane designs.