FCCS - Fluorescence Cross-Correlation Spectroscopy

The FCCS Method

FCCS (Fluorescence Cross-Correlation Spectroscopy) can be measured using the Leica TCS SP8 FCS system. Similar to FCS , it analyzes fluorescence intensity fluctuations derived from a small observation volume. In FCCS potential binding partners are marked with spectrally different fluorophores. Their emitted photons are detected in two separate channels.


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Quantitative parameters derived from cross-correlation curve

The diffusion of double-marked dimers creates synchronized (i.e., correlated) signal fluctuations, while single marked monomers cause independent fluctuations. An increasing amplitude of the cross-correlation curve reflects an enlargement of the bound fraction. Additionally, like in FCS , information about particle concentration, particle mass, viscosity, and bound fraction can be achieved.


FCCS detects high specifically only bound particles that travel together. In contrast to FCS , binding partner can have the same molecular mass.