Prof. Paul Guichard and Dr. Virginie Hamel receive RMS Light Microscopy Award

We are very pleased to announce Prof. Paul Guichard and Dr. Virginie Hamel as joint-winners of the RMS Award for Light Microscopy.

Together, Paul and Virginie have made significant contributions to the development, validation, application, and broad dissemination of Ultrastructure Expansion Microscopy (U-ExM) and its derivatives, including cryo-ExM and iU-ExM.

As co-leaders of the CentrioleLab at the University of Geneva, their work has focused on extending the capabilities of light microscopy to resolve cellular architecture such as centrioles at the nanoscale.

A major objective of their research has been to bridge the longstanding resolution gap between fluorescence light microscopy and electron microscopy in light of understanding organelle architecture. They were among the first to recognise that expansion microscopy could be adapted to faithfully preserve cellular ultrastructure, enabling nanoscale imaging using conventional light microscopes.

They have applied and refined U-ExM across a broad range of biological systems, including human cells1,4–6, parasites such as Toxoplasma, Trypanosoma, and Plasmodium7–9, yeast10, plankton11, and diverse tissues including retina12 and glioblastoma samples in collaboration with clinicians13. These studies illustrated how expansion microscopy can uncover ultrastructural principles that were previously accessible only by electron microscopy,

Building on this foundation, they developed cryo-ExM, combining cryo-fixation with expansion microscopy via established freeze-substitution workflows used in electron microscopy14. This approach significantly improves structural preservation and minimises fixation-induced artefacts, demonstrating that high-resolution fluorescence imaging can be achieved alongside near-native ultrastructural preservation.