Response of organic solvents to vitrification and electron exposure in cryo-TEM experiments

Cryogenic transmission electron microscopy (cryo-TEM) has impacted biology and materials science profoundly due to its power in studying aqueous specimens. However, it remains challenging to extend this technique to organic solvent systems as organic solvents are often difficult to vitrify and are unstable under electron beams. Here, we studied the response of the 23 most commonly used organic solvents to vitrification and electron exposure in cryo-TEM experiments. Optimized vitrification method was determined for each of the solvents, and the electron tolerances of the solvents were thoroughly measured using high-resolution imaging. Generic rules underlying the different performances of the solvents were discussed. Based on the rules, methods were developed to enhance the electron exposure stability of the organic solvents. Our results provide guidance for optimizing cryo-TEM experiments on organic solvent specimens.