In a recent article in Physical Chemistry Chemical Physics, Wobma et al. describes the development of an apparatus capable of direct multicolour fluorescence cross-correlation spectroscopy using polystyrene beads loaded with Cytodiagnostics quantum dots.

Unlike techniques such as Förster Resonance Energy Transfer (FRET) or dual-colour fluorescence cross-correlation spectroscopy (FCCS), this method can provide rapid, real-time analysis of associations between three fluorescent species.

The authors chose using quantum dots due to the excellent spectral separation of these fluorescent nanocrystals, which they state minimize spectral cross-talk and allows for improved cross-correlation analysis. Although, the developed technique can also potentially be used with organic fluorescent dyes, the authors state that since many organic dyes have significant spectral tails to longer wavelengths the effect of cross-talk on cross-correlation must be taken into account and calculated.

This is a promising new technique that can potentially open up a new avenue to study complex protein interactions and ligand exchanges such as those in signal transduction pathways.

The full text article can be found here.