In situ cryo-electron microscopy and tomography of cellular and organismal samples.

As cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET) continue to advance, the ability to visualize cellular and organismal structures with unprecedented clarity is redefining the landscape of structural biology. Breakthroughs in imaging technology, sample preparation and image processing now enable the detailed elucidation of cellular architecture, macromolecular organization, and dynamic biological processes at sub-nanometer resolution. Recent methodological advances have propelled the field to new frontiers, facilitating the investigation of complex biological questions across scales-from macromolecular complexes to organism-wide structural insights. This review explores rapidly emerging trends, highlights key innovations that are pushing the boundaries of in situ structural biology, and addresses persistent challenges in expanding the applicability of cryo-EM and cryo-ET across diverse biological systems.