Of course it's been done, and there are lots of different stains available: https://www.agarscientific.com/general-consumables/chemicals...

Wow you know it’s a fun party when the first result needs to specify it’s _not_ radioactive

Oh I see - Uranyl Acetate is radioactive and this replaces it. Fun!

This seems like a friendly chemical too - “ The chemical properties of Osmium Tetroxide are such that use and handling of the chemical is often considered daunting. Although its volatility and toxicity certainly makes it a dangerous chemical, but when following the proper procedure and taking the necessary precautions, Osmium Tetroxide can be used to its full potential with limited risk to the user.

This is more toxic than glutaraldehyde and has a higher vapour pressure. Particular care must be taken to avoid breathing the vapour or allowing it to affect the eyes. ”

Uranyl acetate for staining is typically depleted and unless you have regulatory issues I don't think the radiation is a big concern, especially when you compare to the very serious toxicity of OsO4 (vapors can react with your eyes and blind you).

Interesting and makes sense! I know nothing but what I read from the stain description haha. OsO4 seems incredibly nasty. So do a few other of the stains!