Characterization of brightness and stoichiometry of bright particles by flow-fluorescence fluctuation spectroscopy.

ABSTRACT: Characterization of bright particles at low concentrations by fluorescence fluctuation spectroscopy (FFS) is challenging, because the event rate of particle detection is low and fluorescence background contributes significantly to the measured signal. It is straightforward to increase the event rate by flow, but the high background continues to be problematic for fluorescence correlation spectroscopy. Here, we characterize the use of photon-counting histogram analysis in the presence of flow. We demonstrate that a photon-counting histogram efficiently separates the particle signal from the background and faithfully determines the brightness and concentration of particles independent of flow speed, as long as undersampling is avoided. Brightness provides a measure of the number of fluoresce

SUBMITTER: Johnson J 

PROVIDER: S-EPMC2966004 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature