荧光淬灭

荧光淬灭（英語：Quenching）是指荧光物质的荧光强度降低的任何过程。许多过程都会导致淬灭现象，例如激发态反应、能量转移、配合物的形成和碰撞淬灭。氧分子、碘离子和丙烯酰胺都是常见的化学淬灭剂^[1]，氯离子是常见的奎宁淬灭剂^[2]^[3]^[4]。

淬灭被用于制造光极（英语：optode）传感器，例如氧对某些钌配合物的淬灭效应可以用于测量溶液中的氧饱和度；淬灭是荧光共振能量转移（FRET）分析技术的基础^[5]^[6]^[7]；特定标靶分子结合时的淬灭与去淬灭效应可用作光学造影剂 ^[8]^[9]；许多染料有自淬灭现象，导致荧光显微镜的蛋白质-染料偶联物的亮度降低^[10]；或是用作检测蛋白酶解传感器^[11]。

淬灭机理

荧光共振能量转移

荧光淬灭可以用多种机制解释，其中的FRET是动态淬灭机制，供体与受体通过非辐射的方式转移能量。因为能量转移的过程基于二者的跃迁偶极间的经典偶极-偶极相互作用，因此极其依赖于供体-受体间的距离R，以E∝1/R⁶的效率下降^[12]，通常FRET过程在100 Å的距离内发生。FRET的过程还取决于供体-受体的重叠（如图）以及跃迁偶极矩的相对取向。

德克斯特电子转移

德克斯特电子转移（英语：Dexter electron transfer）（或称为德克斯特电子交换、碰撞能量转移等）是另一种动态淬灭机制^[13]，同样此过程依赖于供体和受体间的距离，能量转移速率由下式所示，此过程通常在10 Å的距离内发生^[14]，式中 $r$ 是供体与受体间的距离， $L$ 与 $P$ 是不易由实验得到的常量， $J$ 是重叠光谱的积分^[15]。

k_{ET}\varpropto P^{2}J\mathrm {exp} \left[{\frac {-2r}{L}}\right]

激基配合物

激发态配合物的形成过程是第三种动态淬灭过程。

静态淬灭

剩余的能量转移机理是静态淬灭，静态淬灭发生在基态的荧光分子与淬灭剂通过结合形成配合物时，即激发发生之前。静态淬灭形成的配合物会失去荧光性。

碰撞淬灭

激发态的荧光基团与淬灭剂原子或分子碰撞时，以无辐射跃迁的方式回到基态，此种淬灭过程称为碰撞淬灭。

参考文献

^ Acrylamide and iodide fluorescence quenching as a structural probe of tryptophan microenvironment in bovine lens crystallins. Phillips SR, Wilson LJ, Borkman RF. Curr Eye Res. 1986 Aug;5(8):611-9.
^ Fluorescence experiments with quinine James E. O'Reilly J. Chem. Educ., 1975, 52 (9), p 610 doi:10.1021/ed052p610
^ Photophysics in a disco: Luminescence quenching of quinine LouAnn Sacksteder , R. M. Ballew , Elizabeth A. Brown , J. N. Demas , D. Nesselrodt and B. A. DeGraff J. Chem. Educ., 1990, 67 (12), p 1065 doi:10.1021/ed067p1065
^ Halide (Cl-) Quenching of Quinine Sulfate Fluorescence: A Time-Resolved Fluorescence Experiment for Physical Chemistry Jonathan H. Gutow J. Chem. Educ., 2005, 82 (2), p 302 doi:10.1021/ed082p302
^ Peng X, Draney DR, Volcheck WM. Quenched near-infrared fluorescent peptide substrate for HIV-1 protease assay. Achilefu S, Bornhop DJ, Raghavachari R (编). Optical Molecular Probes for Biomedical Applications 6097. 2006: 60970F. S2CID 98507102. doi:10.1117/12.669174.
^ Peng X, Chen H, Draney DR, Volcheck W, Schutz-Geschwender A, Olive DM. A nonfluorescent, broad-range quencher dye for Förster resonance energy transfer assays. Analytical Biochemistry. May 2009, 388 (2): 220–8. PMID 19248753. doi:10.1016/j.ab.2009.02.024.
^ Osterman H. The Next Step in Near Infrared Fluorescence: IRDye QC-1 Dark Quencher.. Review Article. 2009, 388: 1–8. （原始内容存档于20 March 2020）.
^ Blum G, Weimer RM, Edgington LE, Adams W, Bogyo M. Comparative assessment of substrates and activity based probes as tools for non-invasive optical imaging of cysteine protease activity. PLOS ONE. July 2009, 4 (7): e6374. Bibcode:2009PLoSO...4.6374B. PMC 2712068 . PMID 19636372. doi:10.1371/journal.pone.0006374 .
^ Weissleder R, Tung CH, Mahmood U, Bogdanov A. In vivo imaging of tumors with protease-activated near-infrared fluorescent probes. Nature Biotechnology. April 1999, 17 (4): 375–8. PMID 10207887. S2CID 12362848. doi:10.1038/7933.
^ Jacobsen MT, Fairhead M, Fogelstrand P, Howarth M. Amine Landscaping to Maximize Protein-Dye Fluorescence and Ultrastable Protein-Ligand Interaction. Cell Chem Biol. August 2017, 24 (8): 1040–1047. PMC 5563079 . PMID 28757182. doi:10.1016/j.chembiol.2017.06.015 .
^ Voss EW J, Workman CJ, Mummert ME. Detection of protease activity using a fluorescence-enhancement globular substrate. BioTechniques. February 1996, 20 (2): 286–291. PMID 8825159. doi:10.2144/96202rr06. 温哥华格式错误 (帮助)
^ Moens P. Fluorescence Resonance Energy Transfer spectroscopy. [July 14, 2012]. （原始内容存档于2016-07-26）.
^ 國際純化學和應用化學聯合會，化學術語概略，第二版。（金皮書）(1997)。在線校正版: (2006–) "Dexter excitation transfer (electron exchange excitation transfer)"。doi:10.1351/goldbook.D01654
^ Dexter Energy Transfer. chemwiki.ucdavis.edu. 2 October 2013 [8 July 2014]. （原始内容存档于2014-07-14）.
^ 國際純化學和應用化學聯合會，化學術語概略，第二版。（金皮書）(1997)。在線校正版: (2006–) "Dexter excitation transfer (electron exchange excitation transfer)"。doi:10.1351/goldbook.D01654

[1] Acrylamide and iodide fluorescence quenching as a structural probe of tryptophan microenvironment in bovine lens crystallins. Phillips SR, Wilson LJ, Borkman RF. Curr Eye Res. 1986 Aug;5(8):611-9.

[2] Fluorescence experiments with quinine James E. O'Reilly J. Chem. Educ., 1975, 52 (9), p 610 doi:10.1021/ed052p610

[3] Photophysics in a disco: Luminescence quenching of quinine LouAnn Sacksteder , R. M. Ballew , Elizabeth A. Brown , J. N. Demas , D. Nesselrodt and B. A. DeGraff J. Chem. Educ., 1990, 67 (12), p 1065 doi:10.1021/ed067p1065

[4] Halide (Cl-) Quenching of Quinine Sulfate Fluorescence: A Time-Resolved Fluorescence Experiment for Physical Chemistry Jonathan H. Gutow J. Chem. Educ., 2005, 82 (2), p 302 doi:10.1021/ed082p302

[5] Peng X, Draney DR, Volcheck WM. Quenched near-infrared fluorescent peptide substrate for HIV-1 protease assay. Achilefu S, Bornhop DJ, Raghavachari R (编). Optical Molecular Probes for Biomedical Applications 6097. 2006: 60970F. S2CID 98507102. doi:10.1117/12.669174.

[6] Peng X, Chen H, Draney DR, Volcheck W, Schutz-Geschwender A, Olive DM. A nonfluorescent, broad-range quencher dye for Förster resonance energy transfer assays. Analytical Biochemistry. May 2009, 388 (2): 220–8. PMID 19248753. doi:10.1016/j.ab.2009.02.024.

[7] Osterman H. The Next Step in Near Infrared Fluorescence: IRDye QC-1 Dark Quencher.. Review Article. 2009, 388: 1–8. （原始内容存档于20 March 2020）.

[8] Blum G, Weimer RM, Edgington LE, Adams W, Bogyo M. Comparative assessment of substrates and activity based probes as tools for non-invasive optical imaging of cysteine protease activity. PLOS ONE. July 2009, 4 (7): e6374. Bibcode:2009PLoSO...4.6374B. PMC 2712068 . PMID 19636372. doi:10.1371/journal.pone.0006374 .

[9] Weissleder R, Tung CH, Mahmood U, Bogdanov A. In vivo imaging of tumors with protease-activated near-infrared fluorescent probes. Nature Biotechnology. April 1999, 17 (4): 375–8. PMID 10207887. S2CID 12362848. doi:10.1038/7933.

[10] Jacobsen MT, Fairhead M, Fogelstrand P, Howarth M. Amine Landscaping to Maximize Protein-Dye Fluorescence and Ultrastable Protein-Ligand Interaction. Cell Chem Biol. August 2017, 24 (8): 1040–1047. PMC 5563079 . PMID 28757182. doi:10.1016/j.chembiol.2017.06.015 .

[11] Voss EW J, Workman CJ, Mummert ME. Detection of protease activity using a fluorescence-enhancement globular substrate. BioTechniques. February 1996, 20 (2): 286–291. PMID 8825159. doi:10.2144/96202rr06. 温哥华格式错误 (帮助)

[12] Moens P. Fluorescence Resonance Energy Transfer spectroscopy. [July 14, 2012]. （原始内容存档于2016-07-26）.

[13] 國際純化學和應用化學聯合會，化學術語概略，第二版。（金皮書）(1997)。在線校正版: (2006–) "Dexter excitation transfer (electron exchange excitation transfer)"。doi:10.1351/goldbook.D01654

[14] Dexter Energy Transfer. chemwiki.ucdavis.edu. 2 October 2013 [8 July 2014]. （原始内容存档于2014-07-14）.

[det1-15] 國際純化學和應用化學聯合會，化學術語概略，第二版。（金皮書）(1997)。在線校正版: (2006–) "Dexter excitation transfer (electron exchange excitation transfer)"。doi:10.1351/goldbook.D01654

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