AlphaScreen® relies on hydrogel coated Donor and Acceptor beads providing functional groups for conjugation to biomolecules.
The beads come in close proximity when the biomolecules interact by molecular binding, e.g. antibody-antigen or receptor-ligand. Laser excitation at 680 nm of a photosensitiser present on the Donor bead results in the production of singlet oxygen. The singlet oxygen migrates to react with chemiluminescers on the Acceptor bead. The chemiluminescers then activates fluorophores emitting light at 520 - 620 nm. This reaction cascade results in a huge amplification of the signal.
AlphaScreen® has proven to be a reliable and sensitive method in detection assays for secondary messengers like cyclic AMP or IP3 activity. In addition it is a homogenous method well suited for miniaturisation and the use in drug discovery screening.
AlphaScreen is a registered trademark of PerkinElmer.