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.
Luminex Technology Advantages
The Luminex xMAP technology has many advantages over other methods of detecting and measuring biomarkers.
- Flexibility to singleplex or multiplex, simultaneously measuring many targets in a single sample
- Reduced cost and labor by multiplexing
- Track biological interactions in real time
- Luminex assays have smaller sample requirements than other techniques such as ELISA
- Beads have a larger surface area than a flat surface, increasing the range of detection
- Liquid reaction kinetics give faster, more reproducible results than planar arrays
- Single platform for a wide variety of applications, including analysis of proteins (including phosphoproteins), signaling molecules and nucleic acids
- Wide variety of Luminex kits designed for disease, cytokine, growth factor, etc. assays
- Kits available for human, monkey, mouse, and rat
- Bio-Plex Assay Builder for designing customized assays
- Kits available for coupling magnetic or nonmagnetic beads to your proteins or nucleic acids
Bio-Plex System Components
Bio-Plex systems with Luminex technology enable fast, accurate flexible measurement of the upregulation and downregulation of multiple biomarkers in real time. There are several components of Bio-Plex systems.
Bio-Plex Suspension Array Systems: These systems are complete Luminex microplate assay systems. They include two lasers: the classification laser (635 nm excitation), for identifying the bead signatures, and the reporter laser (532 nm excitation), for detecting the target. Bio-Plex Luminex array readers have high-throughput fluidics, system tools for calibration and validation, and management software.
Bio-Plex Software: There are a range of software options for system management, calibration and validation, protocol design, data acquisition, data analysis, and data export and reporting. For clinical and other critical uses, the Bio-Plex Manager™ software, Security Edition provides all the tools necessary for complying with FDA CFR 21 Part 11.
Bio-Plex Pro™Assays: Kits are available for a wide array of studies including cell signaling, cytokines, cancer, diabetes, and angiogenesis. Assays are offered as premixed panels, custom mixes (designed by the Bio-Plex Assay Builder), or singleplex sets.
Carboxylated (COOH) beads and an amine coupling kit can be used to attach any protein or nucleic acid to either magnetic or nonmagnetic beads to generate your own assays.