Investigating the impact of cholesterol on magnetically aligned sphingomyelin/cholesterol multilamellar vesicles using static 31P NMR

The effect of cholesterol (5–40 mol%) on the magnetic induced orientation of sphingomyelin/cholesterol multilamellar vesicles (MLVs) was examined using static solid state 31P NMR spectroscopy. The orientation was modeled assuming an ellipsoidal deformation of the vesicles and was monitored as a function of cholesterol concentration and temperature. In addition, the static 31P chemical shift anisotropy (CSA) was used to assess the motional and dynamical changes occurring in the bilayer are reported. An exploration of the factors determining the magnetic orientation in sphingomyelin/cholesterol bilayers from the gel (so) to liquid crystalline (or liquid-ordered, lo) phases is presented and discussed.