Researchers in the realm of scientific research constantly strive for more efficient, accurate, and streamlined methods of detection and quantitation. One such innovation, which stands as a testament to this endeavor, is Lumit™ Technology, developed by Promega. Pioneering a new era in immunodetection, Lumit™ Technology enables bioluminescence-based detection of specific antigens, thus simplifying immunoassay protocols and accelerating time to results.
At the heart of Lumit™ Technology is NanoBiT® complementation, a system based on the enzyme nano-luciferase, which is split into two subunits – Large bit (LgBiT) and Small bit (SmBiT). These subunits are chemically conjugated to antibodies that are designed to bind to a specific target antigen or analyte.
In the absence of the target, the LgBiT and SmBiT subunits exist separately and are unable to emit light. However, when the target antigen is present, the antibodies bind to it, bringing the LgBiT and SmBiT subunits into close proximity. This proximity allows the LgBiT and SmBiT to reassemble into an active luciferase enzyme.
Upon addition of a substrate, the reformed luciferase enzyme can catalyze a reaction that produces a luminescent (=bright light) signal. The intensity of this signal is directly proportional to the amount of target antigen present, allowing for quantitative measurement of the antigen.
The NanoBiT® complementation system is sensitive and specific, enabling detection of even low levels of native proteins, due to the use of luminescence rather than the less sensitive optical density measurement, seldom used in competitive methods.
Furthermore, in the Lumit assay workflow the detection process is simplified removing the need for immobilization of antibodies to plates/beads, multiple wash steps, or even the need to remove the sample from the original experimental cell culture well. The Lumit™ Immunoassays for cytokine detection, for example, quantitatively measure target analytes in cell culture samples with a simple, no-wash assay protocol. Simply add the Lumit antibodies directly to the cell culture samples or to conditioned medium transferred from cell plates.
Thus, Lumit™ Immunoassays provide a quick, easy, and reliable method for antigen detection. This technology harnesses the power of bioluminescence to revolutionize the field of immunodetection, promising to streamline workflows and improve the speed and accuracy of results in research and clinical applications.
Lumit™ vs. ELISA: The Dawn of a New Era in Immunoassays
Lumit™ Immunoassays are positioned as a faster, more reliable and more sensitive (displaying a broad dynamic range) alternative to traditional ELISAs. The latter, although widely used, are often plagued by variability associated with multiple wash steps and need for calibration and sample dilution. Lumit™ Immunoassays, on the other hand, eliminate this variability, offering a convenient and sensitive luminescent detection method. This efficiency, coupled with the simplicity of the Lumit™ protocol, makes these assays easily adaptable for automation, particularly in labs processing large numbers of samples.
A Look at Lumit™ Immunoassay Options
Promega offers an array of Lumit™ Immunoassays to suit various research needs. These include pre-built assays for detecting popular targets such as cytokines, glucagon, insulin and phosphorylated (and total) intracellular proteins. There are also Lumit technology based kits for analyzing and measuring Fc receptor binding, for those of you out there designing antibodies. Moreover, Promega provides antibody labeling kits and detection reagents, empowering researchers to create their own assays. The company’s custom team also stands ready to assist in developing custom assays.
Lumit™ customizable reagents
Researchers who can’t find their favorite target in Promega’s shelf products portfolio can customize their own Lumit assay by labeling pairs of antibodies towards a desired target, one with the SmBiT and the other with the LgBiT (any antibody, from any supplier), thereby creating their own Lumit™ Assays. Another option for customizing these assays is to use unlabeled primary antibodies (again any antibody, from any supplier) and use Promega’s commercial secondary SmBiT/LgBiT labeled antibodies for detection. The limitation of using this system is that the primary Abs are required to be each from a different species (available options include rabbit, mouse or goat).
Lumit™ FcR Binding Immunoassay
This assay measures the interaction between human FcR (various types of FcgRs and FcRn) and Fc of antibodies. It employs a competition assay method, wherein a human relevant IgG labeled with LgBiT (Tracer-LgBiT) is used as the tracer, and a C-terminal biotinylated human FcR bound to Streptavidin-SmBiT is used as the target. In the absence of an antibody analyte sample, Tracer-LgBiT binds to the hFcR-SmBiT target, resulting in a maximum luminescence signal. Unlabeled user-designed IgG competes with Tracer-LgBiT for binding to the FcR target, thus leading to a concentration-dependent decrease in the luminescent signal.
While there are multiple Lumit™ Immunoassay options, the technology at its core remains consistent—simplified, fast, and accurate detection of analytes via a bioluminescent signal. This luminescent signal is generated through the interaction of the LgBiT and SmBiT subunits upon binding to the target analyte. By reducing the need for multiple wash steps and offering a straightforward protocol, which can be completed in 70 minutes, Lumit™ Technology emerges as a potential game-changer in the field of immunodetection.
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