Super-resolution microscopy by Ciro Santilli 34 Updated Created
Super-resolution means resolution beyond the diffraction limit.
First you shine a lot of light which saturates most fluorophores, leaving very few active.
They you can observe fluorophores firing one by one. Their exact position is a bit stochastic and beyond the diffraction limit, but so long as there aren't to many in close proximity, you can wait for it to fire a bunch of times, and the center of the Gaussian is the actual location.
From this we see that super-resolution microscopy is basically a space-time tradeoff: the more time we wait, the better spacial resolution we get. But we can't do it if things are moving too fast in the sample.
Tradeoff with cryoEM: you get to see things moving in live cell. Electron microscopy fully kills cells, so you have no chance of seeing anything that moves ever.
Caveats:
  • initial illumination to saturate most fluorophores I think can still kill cells, things get harder the less light you put in. So it's not like you don't kill things at all necessarily, you just get a chance not to
  • the presence fluorophore disturbs the system slightly, and is not at the same Exact location of the protein of interest