Abnova’s Interactor™ is a high throughput assay system based on time resolved fluorescence resonance energy transfer (TR-FRET). Conventional applications of TR-FRET focus primarily on GPCR second messengers and kinases. Growing interest in protein-protein and protein-nucleic acid interaction assays for follow-on screening of small molecule drugs and biological compounds represent emerging applications of TR-FRET. Furthermore, TR-FRET can be setup for robust and homogeneous sandwich ELISA assay of protein quantification without plate transfer and wash step.
The FRET principle is based on the transfer of energy between two fluorophores, a donor and an acceptor. Typically, donor and acceptor fluorophores are conjugated to distinct antibodies targeting the interacting entities. As the two entities come close enough to each other, excitation of the donor by a light source triggers an energy transfer towards the acceptor, which in turn emits specific fluorescence at a given wavelength. FRET utilizes the long-lived fluorophores combined with detection on a time resolved fluorescence basis. This allows minimization of background fluorescence interference due to compounds and proteins present in biological fluids or serum that are naturally fluorescent but are short-lived compared to the long-lived labels used.