For higher resolution cryo-EM studies, what has replaced the use of negatively stained specimens?

Question

Quizplus · Accepted Answer

For higher resolution cryo-EM studies, the use of frozen-hydrated particles has replaced the use of negatively stained specimens because negatively stained specimens introduce artifacts and distortions that can compromise the resolution of the final image. Frozen-hydrated specimens allow for the imaging of the particles in their native state without the introduction of artifacts from stains or other chemicals.

For Higher Resolution Cryo-EM Studies, What Has Replaced the Use