Deep UV plasmonic enhancement of single protein autofluorescence in zero-mode waveguides

Detecting proteins in the UV range is appealing to take advantage of their natural tryptophan fluorescence and rule out all the issues related with external fluorescence labelling. However, proteins feature a much lower fluorescence brightness than conventional fluorescent dyes. This is where nanophotonics can improve the detection sensitivity.

In a recent Nano Letter article, we report the first demonstration of single protein UV fluorescence enhancement using aluminum zero-mode waveguides nanoapertures. Dedicated strategies were developed to overcome the technical challenges of working in the UV range. This involves optimizing the UV aluminum nanostructures fabrication, counteracting the metal photocorrosion, dealing with the limited photostability of proteins and developing robust analysis tools to extract useful information out of noisy traces.

This unprecedented detection of single protein fluorescence with UV plasmonics paves the way for interrogating individual proteins in their native state and at physiological concentrations.

Also freely available on ArXiv 1909.08227