What you see in this photo is not an actual staining.
In fact, it’s called autofluorescence!
Autofluorescence is the natural emission of light by biological structures.
This photo is a perfect example of autofluorescence. It shows a blood vessel containing red blood cells inside of it. Both blood vessels and red blood cells are highly fluorescent structures.
While autofluorescence might seem beautiful , it is considered problematic at times. High autofluorescence can interfere with the detection of specific fluorescent signals.
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