New controlled environment vitrification system for cryo-transmission electron microscopy: design and application to surfactant solutions.

A newly designed controlled environment vitrification system for cryo-transmission electron microscopy of vitrified samples (cryo TEM) is presented. It significantly reduces the lag-time from blotting to vitrification by means of an optimized blotting procedure. Furthermore, a modified transfer system allows rapid transfer of the vitrified sample into the microscope and reduces the equilibration time. The practicable throughput of samples is thereby markedly increased. This new equipment is used to determine the overall size of individual polymer-like mixed lecithin-bile salt micelles, which very critically depends on the composition of the sample. The quantitative agreement with the results from independent light scattering experiments on the same sample supports the validity and performance of the presented sample preparation and handling procedures. In addition, these experiments demonstrate that cryo TEM experiments not only provide direct structural information, but furthermore permit a quantitative determination of micellar properties.