Similar to FRET, the Homogeneous Time Resolved Fluorescence (HTRF) technology allows to measure the binding between a membrane receptor fused to a fluorophore and a ligand fused to another fluorophore.
It represents a good alternative to FRET or radioactive tests. Among other benefits, it enables to overcome the transient auto-fluorescence of reagents and consumables that contribute to the background noise, by performing a measurement shifted in time by 50 to 150 microseconds after the excitation of the donor fluorophore (CISBIO).
The binding is measured on living whole cells.
The assay is performed under homogeneous conditions and therefore does not require any washing.