Fluorescence Correlation Spectoscopy


Fluorescence Correlation Spectroscopy (FCS) is a fluorescence technique based on confocal microscopy, which revolves on examining the fluorescence signal recorded for mobile fluorescently labelled molecules. As these molecules pass through the detection area they cause temporal fluctuations in the fluorescence signal. The signal is then correlated to obtain physical parameters such as mobility and concentration.

Left: Molecules diffusing through the excitation volume. Right: Typical shape of the autocorrelation function of the recorded fluorescence signal. The molecule concentration is inversely proportional to the amplitude of the curve, while their diffusion coefficient is inversely proportional to the characteristic decay time.


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