Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, United States; Media Lab, Massachusetts Institute of Technology, Cambridge, United States; McGovern Institute, Massachusetts Institute of Technology, Cambridge, United States
Nicholas C Barry
Media Lab, Massachusetts Institute of Technology, Cambridge, United States; McGovern Institute, Massachusetts Institute of Technology, Cambridge, United States
Asmamaw T Wassie
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, United States; McGovern Institute, Massachusetts Institute of Technology, Cambridge, United States
Anubhav Sinha
Media Lab, Massachusetts Institute of Technology, Cambridge, United States; McGovern Institute, Massachusetts Institute of Technology, Cambridge, United States; Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, United States
Abhishek Bhattacharya
Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, United States
Shoh Asano
Media Lab, Massachusetts Institute of Technology, Cambridge, United States
Chi Zhang
Media Lab, Massachusetts Institute of Technology, Cambridge, United States; McGovern Institute, Massachusetts Institute of Technology, Cambridge, United States
Fei Chen
Broad Institute of MIT and Harvard, Cambridge, United States
Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University-Newark, Newark, United States; The Brain Research Institute, New Jersey Institute of Technology, Newark, United States
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, United States; Media Lab, Massachusetts Institute of Technology, Cambridge, United States; McGovern Institute, Massachusetts Institute of Technology, Cambridge, United States; Koch Institute, Massachusetts Institute of Technology, Cambridge, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
We recently developed expansion microscopy (ExM), which achieves nanoscale-precise imaging of specimens at ~70 nm resolution (with ~4.5x linear expansion) by isotropic swelling of chemically processed, hydrogel-embedded tissue. ExM of C. elegans is challenged by its cuticle, which is stiff and impermeable to antibodies. Here we present a strategy, expansion of C. elegans (ExCel), to expand fixed, intact C. elegans. ExCel enables simultaneous readout of fluorescent proteins, RNA, DNA location, and anatomical structures at resolutions of ~65–75 nm (3.3–3.8x linear expansion). We also developed epitope-preserving ExCel, which enables imaging of endogenous proteins stained by antibodies, and iterative ExCel, which enables imaging of fluorescent proteins after 20x linear expansion. We demonstrate the utility of the ExCel toolbox for mapping synaptic proteins, for identifying previously unreported proteins at cell junctions, and for gene expression analysis in multiple individual neurons of the same animal.
