Lighting up biology: The quest to see every molecule in every cell

It may seem that 21st-century biologists have a fantastic array of tools for probing the workings of molecules, cells and organisms. But optogenetics pioneer Ed Boyden won't be satisfied until there are ways to map all the molecules in every cell of the body, simulate their dynamics and learn the "native language" of all cell types. His lab is coming up with new kinds of microscopy in the quest for a complete map of the molecules in an organism. In "expansion microscopy," they apply fluorescent tags to molecules in a cell, infuse the cell with a superabsorbent polymer, and add water. The expanding polymer stretches the cell itself by a hundredfold in volume; now a light microscope can image the cell in 3D with nanoscale precision. They are also applying a form of light-field microscopy to image the dynamics of a living cell. Finally, Boyden's group does far more than describe; their techniques for activating neurons with light are now being used to control cells in experiments and possible therapies. Social media hashtag: #EveryMolecule.