Quenching of quinine fluorescence (right) by chloride ions (left)

[edit] Quenching

Quenching refers to any process which decreases the fluorescence intensity of a given substance. A variety of processes can result in quenching, such as excited state reactions, energy transfer, complex-formation and collisional quenching. As a consequence, quenching is often heavily dependent on pressure and temperature. Molecular oxygen and the iodide ion are common chemical quenchers. Quenching poses a problem for non-instant spectroscopic methods, such as laser-induced fluorescence.

Quenching is made use of in optode sensors; for instance the quenching effect of oxygen on certain rubidium complexes allows the measurement of oxygen saturation in solution. Quenching is the basis for fluorescence resonance energy transfer (FRET) assays^[1][2][3]. Quenching and dequenching upon interaction with a specific molecular biological target is the basis for activatable optical contrast agents for molecular imaging.^[4][5]

[edit] See also

• Quenching in Chemical Industries for extract product from Mother substance.
• Dark quencher, for use in molecular biology.
• Förster resonance energy transfer, a phenomenon on which some quenching techniques rely

[edit] References

1. ^ Peng, X., Draney, D.R., Volcheck, W.M., Quenched near-infrared fluorescent peptide substrate for HIV-1 protease assay, Proc. SPIE, 2006; (6097), [1]
2. ^ Peng, X., Chen, H., Draney, D.R., Volcheck, W.M., A Non-fluorescent, Broad Range Quencher Dye for FRET Assays, Analytical Biochemistry, 2009; (Vol. 388), pp. 220-228. Download PDF
3. ^ Osterman, H., The Next Step in Near Infrared Fluorescence: IRDye® QC-1 Dark Quencher, 2009; Review Article. Download PDF
4. ^ Blum G, Weimer RM, Edgington LE, Adams W, Bogyo M (2009) Comparative Assessment of Substrates and Activity Based Probes as Tools for Non- Invasive Optical Imaging of Cysteine Protease Activity. PLoS ONE 4(7): e6374. doi:10.1371/journal.pone.0006374. Download PDF
5. ^ Weissleder R, Tung CH, Mahmood U, Bogdanov A (1999). "In vivo imaging of tumors with protease-activated near-infrared fluorescent probes". Nat. Biotechnol. 17 (4): 375–8. doi:10.1038/7933. PMID 10207887. 

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