Luminex immunoassays are widely used to detect and quantify multiple analytes in single sample volumes. They follow a similar assay principle to sandwich ELISA assays. Luminex assays employ a bead-based technology to detect upto 100 analytes simultaneously in a single assay sample. Each color-coded bead is dyed distinctly with red and infrared fluorophores, where each region corresponds to a unique spectral signature. Researchers employ Luminex ELISA multiplex assays to analyze several cytokines and biomarkers in pharmaceutical drug development studies.

Luminex multiplex assays are divided into two components, the Luminex instrument, and the Luminex multiplex assay. Luminex ELISA assays not only detect chemokines, cytokines, and growth factors but can also measure gene expressions in normal and diseased study samples. Besides, they provide comparable results with greater throughput and efficiency. Let us explore each of its features in more detail.

Multiplexing capabilities on a single platform

The Luminex assay empowers drug discovery timeline studies by combining gene expression and analyte detection protocols with enhanced sensitivity and quality. Besides, Luminex platforms are specifically designed to identify and quantify several analytes in small volume samples. They employ xMAP technology to quantify upto 100 analytes in single assay volumes. The following section discusses the xMAP technology.

xMAP technology

xMAP stands for multi-analyte profiling. The technology integrates advanced optics, fluidics, and digital signal processing bead-based systems to assess multiple analytes in study samples. They employ a fluorescence-based microsphere labeling that can quantify upto 80 analytes in a single assay reaction. Besides, custom Luminex assays can use this xMAP technology to provide experiments in a wide range of nucleic acid and protein molecules.

There are four primary Luminex instruments, including the Luminex 200, INTELLIFLEX, MAGPIX, and FLEXMAP 3D. Each microsphere can be individually detected using these instruments. Moreover, these instruments follow the principles of quantitative fluorescence microscopy or fluorescence flow cytometry to fulfill every research need.

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Attributes of the Luminex instrument

The Luminex fluidics system arranges each microsphere into a single file and then subjects them to a flow cell. Once these beads enter like a stream of sheath fluid into the flow cell, the instrument assesses individual beads for their color and fluorescence intensity to capture data for each bead.

The Luminex systems use highly sensitive lasers to quantify the analytes present even in smaller quantities. A 532 nm laser excites the streptavidin-PE complex, while another 635 nm excites the fluorophores on the beads to measure the color output. Besides, the INTELLIFLEX systems also have an additional 405 nm laser to estimate two different parameters on a single bead region.

Moreover, the instrument consists of several detectors. Each detector has an individual application. Detector units can determine the beads, measure fluorescent activity, and differentiate between aggregate and single beads.

Besides, customized assay designs combined with FLEXMAP 3D and INTELLIFLEX systems provide high throughput applications. They can identify multiple analytes in a single well to acquire extensive data points over several samples. This comprehensive data from a single assay well ensure better decision-making when studying immune responses, screening compounds, and much more.