What is luminescence?

Luminescence is the emission of light by a substance as a result of a chemical reaction (chemiluminescence) or an enzymatic reaction (bioluminescence).

luminescence overview left

Luminescence detection is optically simpler than fluorescence detection as it does not require a light source or specific optics for excitation.

luminescence right side overview

Figure 1 - Flash and Glow reaction

Luminescence can be either a ‘flash’ or a ‘glow’ reaction, depending on the kinetic profiles. Flash luminescence gives a very bright signal for a short amount of time, usually seconds. Glow luminescence emits a more stable but usually less intense signal that can last for several minutes or hours. Flash luminescence generally requires a detection system with injectors that can deliver substrate to the reaction shortly before taking a measurement so that signal is not missed. White microplates are usually recommended for luminescence as they reflect light and maximize the signal. (see Figure 1)

Advantages of luminescence

Luminescence is an extremely popular detection platform for many applications compared to absorbance and fluorescence. It generally offers a wider dynamic range and a higher sensitivity as background interference (autofluorescence from compounds, media and cells) is low. In addition, luminescence assays often use a homogenous (no wash) protocol, which makes them simpler to automate for high-throughput applications.

 

  • How does luminescence detection work?

    How does luminescence detection work?

    Unlike fluorescence, where a molecule emits light upon excitation by an external light source, luminescence is generated by a chemical or biological reaction, for example an enzyme and its substrate. The resulting light can be detected by a photomultiplier tube (PMT), in which photons are converted to electrons, with the resulting current proportional to the amount of light. Measurement of the signal is expressed as relative light units (RLU).

    Learn more about our luminescence reader  

    How does a luminometer work?

    How does a luminometer work?

    When a luminescence reaction is set up in a microplate, a luminometer (or luminescence microplate reader), is used to measure the amount of light produced. The microplate is placed in a light-tight read chamber, and light from each well is detected in turn by a PMT. The luminescence readings are expressed as RLU.

    In most luminescence applications the total light produced by the sample is measured, without the selection of particular wavelengths. But for other applications like BRET, a luminescence plate reader can be equipped with filters or monochromators that allow the selection of specific wavelengths in order to measure binding or other biomolecular events.

    Learn more about the SpectraMax L Microplate Reader  

  • NanoBRET/BRET

    NanoBRET/BRET

    BRET (bioluminescence resonance energy transfer) is a technique for measuring protein-protein or protein-ligand interactions that involves the interaction of a bioluminescent donor and a fluorescent acceptor.

    Detection of NanoBRET signals, and analysis of the resulting data, requires sensitive instrumentation and advanced software. Register to learn more:

    Single and Dual Luciferase Reporter Gene Assays

    Single and Dual Luciferase Reporter Gene Assays

    Reporter gene assays are important tools for studying gene expression associated with the activation of cellular pathways. Cells are transfected with a plasmid containing the reporter gene and a sequence of interest, typically a promoter or other transcriptional control element. When the promoter is activated, the reporter gene is expressed and its levels can be measured.

    Learn more about dual luciferase reporter gene assay:

  • Customer Breakthrough

    Customer Breakthrough

    University of Geneva uses the SpectraMax® L Microplate Reader for luciferase-based assays

    To support vital work at the University of Geneva, M.Yves Cambet’s group use a variety of state-of-the-art microplate readers including the SpectraMax L for luciferase-based assays.

    Read more  

    Reactive Oxygen Species (ROS)

    Reactive Oxygen Species (ROS) are chemically reactive molecules containing oxygen. In eukaryotes, these molecules are mainly created during aerobic respiration and can cause problems, such as DNA damage and lipid peroxidation, resulting in cellular damage.  

    In this application note, we demonstrate how SpectraMax® microplate readers can be used to accurately quantify ROS levels using a luminescence-based assay.

  • Cytotoxicity Assays

    Cytotoxicity Assays

    Cytotoxicity is often measured in response to an experimental treatment or potential drug. Having a way to easily screen cytotoxicity in treated cells is critical to identifying new therapeutic treatments or understanding cellular signaling pathways that affect cell health. Common indicators of cytotoxicity include the ATP level in a cell population and integrity of cellular membranes, both of which can be measured using a variety of microplate-based assays.

    Learn more about cytotoxicity in cells:

    ATP-based Cell Viability Assays

    ATP-based Cell Viability Assays

    Molecular Devices SpectraMax® i3x MultiMode Microplate Reader, in combination with luminescent assays for cell viability and cytotoxicity, provides a sensitive and rapid way to measure the number of viable cells in culture and quantify the cytotoxic effects of experimental treatment.

    Learn about the CellTiter-Glo Luminescent Cell Viability Assay and more:

  • Chemiluminescent ELISA

    Chemiluminescent ELISA

    Vascular endothelial growth factors (VEGFs) are a family of secreted polypeptides that have been implicated in mammalian vascular development and in disease processes involving abnormal blood vessel growth.

    Learn more about chemiluminescent ELISA method using our luminometer and data acquisition and analysis software:

    Mycoplasma Monitoring

    Mycoplasma Monitoring

    Mycoplasma, the smallest and simplest of the prokaryotes, are common contaminants of cell cultures. Symptoms of mycoplasma contamination include a reduction in the rate of proliferation and changes in cellular responses, including gene expression

    Learn how the MycoAlert Assay and MycoAlert PLUS Assay from Lonza provide a rapid and convenient way to detect viable mycoplasma in cell cultures using a luminescence microplate reader

Resources of Luminescence

Related Products of Luminescence

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