Hi!

I measure small extarcellular vesicles (sEV) isolated from human blood plasma and very often I see fluorescence. I have read that plasma is prone to this. However, I have not figured out why. Can anyone answer me?

The protocol used:

Raman characterization of sEVs was carried out with a Senterra II microscope (Bruker) in backscattering configuration. The samples were centrifuged, drop-casted on a calcium fluoride substrate and air-dried at room temperature before the analysis. All the samples were analyzed using the same configuration parameters based on preliminary studies: nominal laser power 12.5 mW, integration time 30 s (2 coadditions), interferometer resolution 1.5 cm−1, excitation wavelength 532 nm. The spectra from all the samples were collected by using a 50× optical objective (Olympus).