Förster (or fluorescence) resonance energy transfer (FRET) Microscopy

FRET is a process by which radiationless transfer of energy occurs from a fluorophore molecule in the excited state to a molecule in close proximity in the ground state. The molecule donating the energy is called 'Donor' (D) and the molecule accepting the energy is called 'Acceptor' (A). When this occurs, the donor is said to be quenched and the acceptor is sensitized and the event becomes inter alia the basis for calculating proximities between molecules, providing a non-invasive approach to visualize the spatio-temporal dynamics of the interactions between protein partners in living specimens. Suitable fluorophore FRET partners are one of the keys for a successful FRET application. FRET pairs can be selected from exogenous and endogenous fluorophores, the former being organic dyes, visible fluorescent proteins and quantum dots. An important criterion for the FRET pair selection is the Förster distance (Ro); a larger Ro will increase the likelihood of a FRET event.

This FRET approach is implemented in all above mentioned microscopy systems. If it is an intensity based system, after data acquisition the image should be corrected for spectral bleedthrough contamination using the PFRET software as explained briefly in the software section. We also have all the required filters for many available FRET pairs.