Jueun Sim

Systematic understanding of biological systems necessitates investigating the entire organism at subcellular levels, but this has not yet been achieved. Here, we demonstrate whole-body ExM, which enables three-dimensional nanoscale imaging of anatomical features across the entire vertebrate by expanding the whole organism four-fold. To accomplish this, we developed an expansion protocol suitable for whole-body vertebrates with calcified body parts. The two keys to the whole-body ExM process were digestion kinetics matching and post-digestion decalcification. Through this process, we successfully revealed the nanoscale details of diverse organs, which have corresponding organ counterparts in humans, at the intact organismal level of specimens. Finally, we also verified that whole-body ExM is compatible with target-specific fluorescent labeling methods and that its resolution is high enough to exhibit a wide range of structures that can be imaged only with electron microscopy. We believe that whole-body ExM will pave the way for new developments in biology and medicine with its outstanding performance.