Electrochemiluminescence or electrogenerated chemiluminescence (ECL) is a kind of luminescence produced during electrochemical reactions in solutions. In electrochemiluminescence, electrochemically generated intermediates undergo a high degree of exergonic reaction to produce an electronically excited state and then emits light when relaxed to a lower energy level. This wavelength of emitted photons corresponds to the energy gap between these two states. ECL excitation can be caused by the high energy electron transfer (redox) reaction of the electro-generated material. This luminescent excitation is a form of chemiluminescence in which one/all of the reactants are electrochemically produced on the electrode.
ECL is typically observed during the application of potential to an electrochemical cell electrode in a solution of an aprotic organic solvent (ECL composition) containing a solution of a luminescent material (metal complex, polyaromatic hydrocarbon, nanoparticle, or quantum dot). In organic solvents, the oxidized and reduced forms of the luminescent material can be produced simultaneously on different electrodes, or on a single electrode by scanning the potential between oxidation and reduction. Excitation energy is obtained from the recombination of oxidized and reduced species.
Advantages of electrochemiluminescence
- High sensitivity: Multiple excitation cycles can amplify signals to enhance light levels.
- Broad dynamic range: The wide dynamic range of our detection systems means high and low expression levels can be measured without multiple sample dilutions.
- Low background: The stimulation method (electricity) is decoupled from the signal (light) allowing only labels near the electrode surface to be detected.
- Easy to use: Immunoassay method similar to conventional ELISA, but quicker.
- Great flexibility: Labels are stable, non-radioactive, and conveniently conjugated to biological molecules.
- Unsurpassed performance and quality: Electrochemiluminescence is a highly successful detection system that achieves clinical quality data in a variety of sample types, including cell supernatant, serum, plasma, and whole blood.
- Chem. Rev. 2004, 104, 6, 3003–3036 Publication Date: March 20, 2004 https://doi.org/10.1021/cr020373d
- Electrochemiluminescence (ECL) is a powerful transduction technique with a leading role in the biosensing field due to its high sensitivity and low background signal. Although the intrinsic analytical strength of ECL depends critically on the overall efficiency of the mechanisms of its generation, studies aimed at enhancing the ECL signal have mostly focused on the investigation of materials, either luminophores or coreactants, while fundamental mechanistic studies are relatively scarce. Zanut, A., Fiorani, A., Canola, S. et al. Insights into the mechanism of coreactant electrochemiluminescence facilitating enhanced bioanalytical performance. Nat Commun 11, 2668 (2020). https://doi.org/10.1038/s41467-020-16476-2