A Universal Particle Image Correlation Spectroscopy (UPICS) for the Analysis of Fast and Densely Diffusing Particles

We present a new and universal particle/molecule position correlation method for single molecule microscopy specifically designed to investigate the motional behavior of dense multi-modally diffusing molecules as can be found e.g. in live cell experiments or membrane receptor interaction studies. While single particle tracking based analytical methods due to identity mismatching are restricted in particle number and diffusivities, our new universal particle image correlation spectroscopy (UPICS) approach yields highly correlated step length distributions with ever improving signal to noise ratio for larger population sizes and unprecedented accuracy of diffusivity determination. Neither blinking nor bleaching produce any change in UPICS diffusivities or reduce their accuracy. The application to the diffusion and interaction of membrane receptors (G-protein coupled receptors) will be presented.