cryoscanning

CryoScanning is a family of imaging approaches that use cryogenic temperatures to scan specimens with high resolution while preserving their hydrated, near-native state. The term covers methods such as cryo-scanning electron microscopy (cryo-SEM) and cryo-scanning probe microscopy (cryo-SPM), among others, which share the goal of reducing ice loss, dehydration artifacts, and radiation damage during imaging.

In typical cryoScanning workflows, samples are rapidly frozen (plunge freezing or high-pressure freezing) to vitrify water and immobilize structures. The specimen is kept at cryogenic temperatures throughout transfer to the instrument and during imaging, using cryo-stages cooled with liquid nitrogen or liquid helium. For cryo-SEM, specimens may be fractured to expose internal features and sometimes subjected to controlled sublimation to reveal surfaces before imaging under low temperature and vacuum. For cryo-SPM, a chilled tip interacts with the specimen surface under cryogenic conditions.

Applications include visualization of cellular morphology, macromolecular complexes, viruses, and hydrated tissues, as well as structural studies of polymers, minerals, and ice-containing materials. CryoScanning enables observation of specimens in a state closer to native hydrated conditions than conventional room-temperature techniques.

Advantages include reduced dehydration and shrinkage, minimized beam damage, and enhanced contrast for certain hydrated features. Limitations involve specialized infrastructure and training, potential preparation artifacts from freezing, limited depth information in some modalities, and challenges related to imaging at low temperatures and in vacuum.

CryoScanning reflects a broader trend in microscopy to preserve specimen integrity during imaging, complementing cryo-EM, cryo-TEM, and other cryogenic techniques. It remains an active area of instrument development and methodological refinement.