Luminex xMAP Technology

Luminex Overview

Luminex xMap technology is a bead-based multiplexed immunoassay system in a microplate format. The system can simultaneously detect many targets in a single sample — up to 500, depending on system design.

The microspheres used in the Luminex system have different spectral addresses (color codes). These unique spectral addresses are created by internally labeling beads with different ratios of two fluorophores, one in a red wavelength and the other in the far red. This is the xMAP technology.

Proteins including antibodies, ligands, and nucleic acids specific to the desired targets can be coupled to the beads. Bio-Plex assays use antibodies coupled to the beads. In the kits, every antibody to a different target is covalently attached to beads with a different single spectral address, giving each target its own unique address.

xMAP assays are available in magnetic or nonmagnetic bead formats.

In an assay using the Luminex system, the beads are incubated with a sample. After washing, the beads are incubated with a mixture of biotinylated antibodies against all the targets. After another wash, the beads are incubated with the reporter streptavidin-PE. For targets that are present in the sample, a sandwich is generated that is composed of: bead with attached target-specific antibody + target + biotinylated target- specific antibody + streptavidin reporter.

Using a dual laser system, the signature of each bead is identified, and the presence and intensity of reporter associated with the bead is detected simultaneously. This gives information about both the identity and concentration of targets in the sample.

Luminex xMap technology is particularly powerful when looking for changes in concentrations of multiple targets under different conditions. Two examples are tracking the progress of immune responses to a microbial infection and tracking the development of an autoimmune disease.