Cryo-SEM in haematological research.

Cryogenic scanning electron microscopy (cryo-SEM) is a powerful imaging technique used in cellular biology, providing high-resolution micrographs that show the complexity and dynamics of biological systems. The use of high-pressure freezing (HPF) for specimen fixation preserves cellular structures in their native, hydrated state, avoiding the artefacts introduced by conventional chemical fixation, while modern microscopes provide high-resolution imaging at low electron acceleration voltage, giving fine structural details. That makes cryo-SEM a unique tool for understanding cellular complexity. However, operating the SEM at cryogenic conditions requires careful optimisation of working parameters to avoid artefacts. In our work, we explore the potential of cryo-SEM for haematology and general cell studies. We discuss the impact of a combination of different signals and work distance on specimen appearance and present examples of studies on healthy human blood cells under physiological conditions. Our findings illustrate the breadth of information that can be obtained from these data, highlighting the technique's capacity to enhance our understanding of cellular biology.