Luminex Detection Methods - Molecular Diagnostics & Life Sciences

Luminex Detection Methods - Molecular Diagnostics & Life Sciences
Luminex has several detection method technologies for analyzing the results of assays. Being familiar with these helps to understand how Luminex hardware works.
One detection method Luminex uses to identify beads and if the target is present is called flow cytometry. With flow cytometry the beads are fed into a compartment called a cuvette and are individually scanned buy a red and a green laser. The red 620 nanometer laser excites dyes within the beads to identify the bead region. The red laser works but the set of sensors that detect the dye concentrations of the bead. The green 535 nanometer laser identifies the fluorescence of the reporter molecule. It works with its own sensor. Both the bead ideas mapped and the median fluorescence intensity is measured.
Another detection method is fluorescent imager analysis. This method reads all the beads at once. The beads are all fed into a chamber where they are captured by a magnetized wall. The magnetic MagPlex beads are required for this method. Once the beads are in place, a red 635 nanometer and a green 525 nanometer LED shine on the beads to excite the dyes and reporter. Then a CCD camera is used to identify each bead region as well as quantify the analyte binding events. Once complete the magnet moves away from the chamber releasing the beads to be flushed from the instrument.
Another detection method Luminex uses is fluorimeter detection. This method uses six LEDs that shine on six photodiode detectors using Fiber Optic Cables. Each LED is a different wavelength sand will excite different reporters. A PCR tube containing an assay being run is placed between the LED and photodiode to see if there is fluorescence. The LEDs and reporters are ultraviolet blue, green, white, amber and red. The fluorescence is charted for each Channel and Sample.
Nanoparticle imaging which utilizes Nanogrid technology is another powerful Luminex detection method. This method analyzes slides covered in spots called Nanogrids to detect the presence or absence of targets. Each spot contains a strand of DNA or probe complementary to the various targets of interest. After a series of hybridizations with the sample, nucleic acid mediators, gold nanoparticles and a silver solution help LED lights shine on the slide and camera takes images of the slide at multiple exposures. Any probes or spots that have Incorporated the various hybridization reagents scatter light back to the camera creating a visible spot on the slide if the target nucleic acid is present in the sample. This box with no complimentary samples nucleic acid attachments and therefore no silver coated gold nanoparticles do not scatter light back to the camera and remain dark. The Luminex instrument to determine the presence or absence of light scatter on the Nanogrids.
The detection methods Luminex uses to analyze assays are flow cytometry fluorescent imager analysis detection, fluorimeter detection and nanoparticle imaging. Since different instruments
use different technologies the type of analysis needed for an assay will dictate the instrument used.
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