Demonstrating soft X-ray tomography in the lab for correlative cryogenic biological imaging using X-rays and light microscopy.

Soft X-ray tomography (SXT) enables native-contrast three-dimensional (3D) imaging of fully hydrated, cryogenically preserved biological samples, revealing ultrastructural details without the need for staining, embedding, or sectioning. Traditionally available only at synchrotron facilities, recent advances in laser-driven plasma sources have led to the development of compact soft X-ray microscopes. Achieving a resolution of 54 nm full-pitch and tomogram acquisition times of 30 min to two hours, we validate the system across a range of biologically relevant contexts, including protists, yeast, and mammalian cells containing polymeric and inorganic nanoparticles. These use cases establish the robustness of the laboratory based system for studying cell architecture, organelle interactions, and nanoparticle trafficking. By showing that a compact SXT system can achieve reliable high-resolution imaging across various cell types, this study highlights a major step toward making correlative cryogenic X-ray imaging broadly accessible in laboratory settings. Future developments will aim at enhanced throughput, deeper integration with correlative imaging modalities, and extension to more complex specimen types, including tissue.