Cryo-TEM of micelles and lyotropic liquid crystals in non-aqueous solvents

Abstract

Surfactant molecules can form spherical micelles in water above the critical micellization concentration. At still higher concentrations, they can form thread-like micelles and liquid crystals. Cryo-transmission electron microscopy of these microstructures in water is now used successfully for studying aqueous biological and synthetic systems. The controlled environment vitrification system (CEVS) makes it possible to prepare samples accurately. Further, The on-grid processing makes specimens possible from evolving systems halted in mid-process.Despite all the successes with aqueous systems, imaging of microstructures formed in non-aqueous solvents has not been reported. The main difficulties are radiation damage, thermal drift of the specimen, and low contrast. As small a spot size and as well spread a beam as possible are needed for low magnification searching. During the image recording, the minimum dose and lowest magnification possible are desired in order to avoid the thermal drift and radiation damage while maintaining an adequate signal-to-noise ratio.