Electron‐beam‐induced amorphization of ice III or IX obtained by high‐pressure freezing

Abstract

Cryo‐electron microscopy of vitrified specimens makes it possible to observe fully hydrated biological samples unimpaired by chemical fixation, staining and dehydration. High‐pressure freezing represents important progress since it allows a 10‐fold increase in the vitrification depth. High‐pressure freezing can also induce the formation of undesirable high‐pressure forms of ice. We show that ice III or IX is amorphized under the electron beam at a dose of about 2400 electronsnm−2 and that the resulting amorphous ice is similar to the vitreous water obtained by high‐pressure freezing.