AlphaLISA Acceptor beads coated with anti-DNP antibody. These beads can be used to capture DNP-labeled proteins and other DNP-labeled biomolecules, and can be used in conjunction with Alpha Donor beads to create no-wash assays for:

• Analyte detection assays
• Antibody detection assays
• Antibody binding assays
• Protein-protein interaction assays
• Protein detection assays
• Enzymatic assays

In a typical AlphaLISA assay, 1 mg of Donor beads is sufficient to run 1,000-2,000 wells using a 50 µL reaction volume. Bead concentration can be adjusted for optimal performance.

AlphaScreen® and AlphaLISA™ are bead-based assay technologies used to study biomolecular interactions in a microplate format. The acronym "Alpha" stands for amplified luminescent proximity homogeneous assay. As the name implies, some of the key features of these technologies are that they are non-radioactive, homogeneous proximity assays. Binding of molecules captured on the beads leads to an energy transfer from one bead to the other, ultimately producing a luminescent/fluorescent signal. To understand how a signal is produced, one must begin with an understanding of the beads. AlphaScreen and AlphaLISA assays require two bead types: Donor beads and Acceptor beads. Each bead type contains a different proprietary mixture of chemicals, which are key elements of the AlphaScreen technology. Donor beads contain a photosensitizer, phthalocyanine, which converts ambient oxygen to an excited and reactive form of O₂, singlet oxygen, upon illumination at 680 nm. Please note that singlet oxygen is not a radical; it is molecular oxygen with a single excited electron. Like other excited molecules, singlet oxygen has a limited lifetime prior to falling back to ground state. Within its 4 µsec half-life, singlet oxygen can diffuse approximately 200 nm in solution. If an Acceptor bead is within that proximity, energy is transferred from the singlet oxygen to thioxene derivatives within the Acceptor bead, subsequently culminating in light production at 520-620 nm (AlphaScreen) or at 615 nm (AlphaLISA). In the absence of an Acceptor bead, singlet oxygen falls to ground state and no signal is produced. This proximity-dependent chemical energy transfer is the basis for AlphaScreen's homogeneous nature.