The multi-analyte suspension array is based on Luminex’s XMAP Technology. It uses a liquid suspension array with up to 100 uniquely color-coded bead sets, each bearing a different assay. Each are labeled with a specific ratio (signature) of two fluorophores (excited by red laser) to assign it a unique spectral address (region). When the beads are incubated with sample, the protein of interest (specific analyte) is captured and then a biotinylated antibody for a different epitope is added to the reaction, which is then detected with streptavidin-PE, a reporter molecule, excited by the green laser. The beads are drawn single file through a flow cell where the two lasers excite them.Using a dual-laser-based reader, beads are analyzed for the detection antibody and the internal bead signature (region), identifying both the protein analyzed and the level bound to the bead.This is an alternative to using ELISA assays to determine the concentration of proteins in solution, such as cell lysates or serum. The advantage of doing multiplex assays is that one can get results simultaneously for many proteins dissolved in a very small volume.
Using the user friendly Bio-Plex software, standard curves of known concentration of all analytes are automatically computed and all data from the standards and unknowns can be displayed in graphic or table form. The results can also be saved in either form whichever is preferred by the investigator. Kits for simultaneous quantitative measurement of up to 25-30 proteins are available. Examples of proteins that can be analyzed with commercially prepared Luminex microspheres (polystyrene or magnetic) are human/murine/rat cytokines, human/murine phosphoproteins, growth factors, kinases, transcription factors, and cancer markers. Users may also create custom assays for any proteins having corresponding antibodies. By multiplexing with the Bio-Plex system, researchers can dramatically increase the amount of useful information from rare or volume-limited samples such as mouse or rat serum and decipher complex interrelationships among proteins involved in signal transduction pathways.
Unique to Bio-Plex is the integration of assay kits, software, calibration and validation beads, and instrumentation into a complete and reliable high-throughput multiplex assay system.