ABSTRACT
Nanoscale resolution imaging of whole vertebrates is required for a systematic understanding of human diseases, but this has yet to be realized. Expansion microscopy (ExM) is an attractive option for achieving this goal, but the expansion of whole vertebrates has not been demonstrated due to the difficulty of expanding hard body components. Here, we demonstrate whole-body ExM, which enables nanoscale resolution imaging of anatomical structures, proteins, and endogenous fluorescent proteins (FPs) of whole zebrafish larvae and mouse embryos by expanding them fourfold. We first show that post-digestion decalcification and digestion kinetics matching are critical steps in the expansion of whole vertebrates. Then, whole-body ExM is combined with the improved pan-protein labeling approach to demonstrate the three-dimensional super-resolution imaging of antibody- or FP-labeled structures and all major anatomical structures surrounding them. We also show that whole-body ExM enables visualization of the nanoscale details of neuronal structures across the entire body.
Competing Interest Statement
J.-B.C., J.S., C.E.P., I.C., and K.M. have applied for patents for whole-body ExM (KR patent application 10-2021-0024480, KR patent application 10-2022-0010077, and KR patent application 10-2022-0009372). J.-B.C., Y.-G.Y., J.S., C.E.P., I.C. have applied for patents for whole-body ExM (KR patent application 10-2021-0138718, KR patent application 10-2022-0010078, and US patent application 17675808).