Expansion Microscopy of Larval Zebrafish Brains and Zebrafish Embryos

Since its introduction in 2015, expansion microscopy (ExM) allowed imaging a broad variety of biological structures in many models, at nanoscale resolution. Here, we describe in detail a protocol for application of ExM in whole-brains of zebrafish larvae and intact embryos, and discuss the considerations involved in the imaging of nonflat, whole-organ or organism samples, more broadly.