Simple, Cost-Effective Multiplexing of Immunoassays
Traditionally, single-analyte, or singleplex, protein detection methods such as enzyme-linked immunosorbent assays (ELISA) or western blotting have been used sequentially to analyze multiple intracellular and extracellular proteins. Although these are both well-established, validated techniques, they can be time-consuming, sample-depleting, and costly when used to measure numerous markers per sample.
Advantages of the MAGPIX® System
For the past 10 years, two instrument systems for evaluating assays based on xMAP® technology, the Luminex® 200™ and FLEXMAP 3D® sytems, have gained wide acceptance for use in applications including protein expression profiling, focused gene expression profiling, and disease testing. These instruments analyze the results of fluorescent bead–based assays by separating beads using flow cytometry, exciting them with two lasers, and evaluating the results using real-time, digital signal processing and xPONENT® software to distinguish bead color (analyte) and assay signal-strength (PE) fluorescence intensity.
In contrast, the MAGPIX® system (Figure 1) immobilizes beads with magnetic force, excites them using light-emitting diodes (LEDs), and detects beads and analytes using a CCD camera. The result is a more compact, robust, and cost-effective multiplexing tool. In addition, streamlined startup and shutdown protocols, and minimal maintenance requirements make the system easy to use—ideal for both new and experienced users.
The MAGPIX® system can read up to 50 unique magnetic bead regions. Our assays for the MAGPIX® system use Luminex® MagPlex magnetic microsphere technology that takes advantage of magnetic properties to simplify wash steps and maximize uniformity of results. These assays are compatible with both vacuum and magnetic wash stations, as well as other Luminex® xMAP® platforms. Like the Luminex® 200™ and FLEXMAP 3D® systems, the MAGPIX® system uses xPONENT® software, offering performance and user interaction similar to these more expensive flow cytometry–based systems.
Whether you are testing for single or multiple analytes, the MAGPIX® System and qualified assays from Life Technologies offer accurate analytical performance and efficient, easy-to-follow protocols. In addition, the quantitative analytical results obtained with these assays are routinely compared with those from matching ELISAs to validate that the two methods provide correlated results (Figure 2).
Figure 1. The MAGPIX® system. The new compact and cost-effective Luminex® system for immunoassay mulitplexing performs up to 50 assays simultaneously in each well of a 96-well plate.
High Sensitivity, Accuracy, and Precision of the MAGPIX® System
Consistent, quantitative results can be obtained from the MAGPIX®, Luminex® 200™, and FLEXMAP 3D® systems (Figure 3). In addition, benchmark testing carried out using the MAGPIX® and the Luminex® 200™ systems resulted in comparable limits of detection (LOD) shown for both systems, typically in the 1–20 pg/mL range (Figure 4). Assays performed on the MAGPIX® system provide comparable intra-assay and inter-assay precision with typical coefficient of variation (CV) values of <10% over the concentration range analyzed. Figure 5 shows intra-assay precision for ten representative analytes.
|Figure 3. MAGPIX®, Luminex® 200™, and FLEXMAP 3D® systems provide comparable performance. Tissue culture supernatant was prepared from stimulated cynomolgus monkey PBMCs and analyzed using our Monkey Cytokine 28-Plex Panel. A single assay preparation was split into three assay plates and read simultaneously on each instrument. The results for ten representative analytes are shown.|
|Figure 4. Testing for MAGPIX® and Luminex® 200™ systems. A standard curve was generated by serially diluting the recombinant protein standards provided with the Human Cytokine Magnetic 25-Plex Panel. The LOD of each of the 25 analytes was determined by recalculating the concentration obtained by adding two standard deviations to the background reading for each analyte. The results for ten representative analytes are shown.|
Figure 5. Assay precision on the MAGPIX® system. Protein standards were diluted to the middle and low end of the dynamic range for each analyte in the Human Cytokine Magnetic 25-Plex Panel. Sixteen replicates of each target dilution were assayed in two separate 96-well plates, and the intra-assay precision was calculated. Results from 10 representative analytes are shown.
Single and Multiplex Assays Save Time and Achieve Reliable Results
xMAP® technology offers accurate, reproducible, and sensitive quantification of multiple proteins in a single reaction. We offer a variety of preformulated ELISAs and Luminex® multiplexing assays as well as a comprehensive custom service for designing assays with protein targets you select. Choose from Luminex® assay panels—single-bead sets that you can mix yourself—or custom Luminex® assays built and performance-tested just for you.
For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.
Get a copy of this article as it appears in the print version of BioProbes 66.
See a complete listing of the products discussed in this article.