Luminex multiplex assays is a multi-functional, multi-indicator parallel analysis system that organically integrates color-coded beads, laser technology, applied fluidics, the latest high-speed digital signal processor and computer algorithms to create a high degree of specificity and sensitivity for multi-factor detection. It can be widely used in immunoassay, nucleic acid research, enzymatic analysis, receptor and ligand recognition analysis, and other researches.
Principle of Luminex Multiplex Technology
The core of Luminex technology is the use of polystyrene to produce microspheres. Tiny polystyrene spheres (5.6 microns) are coated with different ratios of red and infrared light dyes to create 100 different colors of microspheres. Each color microsphere is covalently cross-linked with a probe, antigen or antibody targeting a specific assay. The different microspheres bind proteins (antibodies or antigens for immunoassays) against different substances to be detected. The detection antibody is labeled with biotin and stained with a highly sensitive fluorescent dye.
Coded microspheres targeting different assays are mixed and a tiny amount of the sample to be tested is added. In the suspension the target molecules bind specifically to molecules cross-linked on the surface of the microspheres. Up to 100 different biological reactions can be accomplished simultaneously in a single reaction well.
Individual microspheres are passed through the detection channel and the red sorting fluorescence on the microspheres and the green reporter fluorescence on the reporter molecule are detected simultaneously using a two-color laser.
- The red laser excites the red sorting fluorescence on the microspheres, which allows the microspheres to be sorted according to their different color numbers, thus distinguishing the individual analytical reactions from one another.
- The green laser excitation is for green reporter fluorescence molecules and aims to determine the number of reporter fluorescence molecules bound on the microspheres and thus the number of target molecules bound on the microspheres.
The simultaneous detection of the red and green lasers allows the determination of the type and number of bound detectors. The machine and computer then automatically statistically analyze the type and number of microspheres detected by the laser to determine the concentration of multiple target test substances in the sample to be tested. Because the molecular hybridization or immunoassay reaction is performed in suspension solution, the detection is extremely fast, and up to 100 indicators can be detected simultaneously in a micro-liquid reaction system.
Characteristics of Luminex Multiplex Technology
Luminex technology has the following advantages:
- High throughput, 100 indicators can be detected in one operation
- Can be used for both clinical and research purposes
- Low sample volume (only 10 μl of sample is required for testing)
- High speed (up to 10,000 tests/h)
- High sensitivity (low detection limit of 10pg/ml)
- Wide linearity range (up to 6 orders of magnitude)
- Good repeatability
- Low cost
Application of Luminex Multiplex Technology
- Luminex cytokine assay
Cytokine assays have important applications in basic molecular biology research, in revealing the mechanisms of development of certain diseases, and in diagnosis and treatment. Comprehensive monitoring and evaluation of cytokine levels is more clinically relevant than monitoring individual cytokines. Traditional detection methods (molecular biology, immunoassay and biological assay) can only detect one cytokine at a time, and there are problems such as mutual interference, low sensitivity, large variation of measurement results, cumbersome and time-consuming operation. With Luminex xMAP technology, various cytokines such as interleukin, interferon, tumor necrosis factor, colony-stimulating factor, chemokine, and growth factor can be detected.
- Disease marker analysis
Disease marker assays are important in the direction of basic research, early diagnosis, efficacy detection and prognosis evaluation of diseases.
The commonly used methods for disease marker detection include enzyme immunoassay, chemiluminescence, electrochemiluminescence and so on. For tumors and other diseases, most of the individual markers have low sensitivity or specificity and cannot meet clinical needs. The need for simultaneous measurement of multiple markers at one time has increased.
The Luminex xMAP technology can meet the above needs. The principle and characteristics of Luminex xMAP technology can be used to establish a variety of qualitative and quantitative panels for disease markers, and it has obvious advantages in terms of the number of indicators that can be detected at one time, the amount of specimens used, the speed of detection, and reproducibility.
Autoantibodies refer to the immune response of the body's immune system to autoantigenic components such as normal or degenerated tissues, organs, cells, proteins or enzymes by some internal or external factors, and the production of antibodies against auto components by the body's B lymphocytes. Autoantibodies are an important marker of autoimmune diseases, and each autoimmune disease is accompanied by a characteristic autoantibody profile.
Luminex technology uses a double antibody sandwich method on the surface of microspheres to detect autoantibodies, allowing for parallel analysis of multiple indicators.