Magneto-Orientation of Phospholipids

Abstract Magneto-orientation effects were observed for platelets of thin layered single crystals of L- and DL-dipalmitoylphosphatidylcholine (DPPC), and for single crystals of polyethylene (PE) suspended in xylene. For both L- and DL-DPPC crystals, a biaxial magneto-orientation was observed, in which both directions of hydrocarbon chain and phosphorylcholine group were directed perpendicular to the applied field direction. For PE, the hydrocarbon chain direction was oriented perpendicular to the field. From the orientational behaviour under the magnetic field, the anisotropy of diamagnetic susceptibility, the difference between susceptibilities parallel and perpendicular to the hydrocarbon chain direction, is evaluated as − 9 × 10−8 and − 1 × 10−8 emu/cm3 for L-DPPC and PE, respectively. The origin of the diamagnetic anisotropy of DPPC is briefly discussed in terms of the molecular and crystal structures.