Ultraviolet Photostability Improvement for Autofluorescence Correlation Spectroscopy on Label-Free Proteins

2 Avril 2020 , Rédigé par JW

The natural autofluorescence of proteins in the UV is appealing to get the detailed information from single molecule data without requiring a potentially disturbing external fluorescent label. However, proteins feature significantly lower autofluorescence brightness and photostabilities than conventional fluorescent dyes. This issue has largely prevented so far the detection of label-free proteins in the ultraviolet.

In a recent article in the Journal of Physical Chemistry Letters, we use a dedicated combination of oxygen scavengers and reducing agents to promote the protein photostability, reduce the photobleaching probability and improve the net UV autofluorescence signal.


- This is the first time that different photostability improvement strategies are reported and quantitatively assessed for label-free proteins in the ultraviolet range.

- We show that the underlying photochemical concepts initially derived for organic fluorescent dyes are still valid for protein autofluorescence in the UV, and therefore appear to be quite general.

- Fluorescence correlation spectroscopy (FCS) is demonstrated on label-free streptavidin proteins containing only 24 tryptophan residues, 6.5× less than the current state-of-the-art.

Also freely available on ArXiv 2002.09761


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