Small-angle scattering and electron microscopy investigation of nanotubules made from a perfluoroalkylated glucophospholipid

Anionic glucophospholipids were recently reported as a new family of tubule -forming lipids. We report here investigations on the structure of nanotubu les made from a glucophospholipid with a mixed fluorocarbon-hydrocarbon hyd rophobe, using freeze fracture and cryo-transmission electron microscopy (T EM) and X-ray and neutron small angle scattering (SAXS, SANS). The hollow a nd regularly shaped tubules are very thin: they have an external radius of 140 Angstrom and an internal radius of 35 Angstrom on the average, Their 10 5 Angstrom-thick wall appears to consist in three bilayers in which the glu cophospholipid molecules are probably in a tilted and/or interdigitated con figuration. Upon heating these nanotubes convert reversibly into vesicles; transformation is complete at 60 degrees C. (C) 1999 Academic Press.