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Title: SU-F-T-676: Measurement of Hydroxyl Radicals in Radiolized Water Systems

Abstract

Purpose: Hydroxyl radicals can be produced within tissue by radiation therapy, and they are largely responsible for DNA damage and cell killing. Coumarin-3-carboxylic acid (3-CCA) and crystal violet are reported to react with hydroxyl radicals and can be used for fluorescence and absorbance measurements, respectively. This study assesses the ability of hydroxyl measurement for both 3-CCA and crystal violet in radiolized water systems in order to provide dosimetric information in radiation chemistry and radiation biology experiments. Methods: 3-CCA and crystal violet were both dissolved in phosphate buffered saline (PBS, pH 7.4) with final concentrations 0.5 mg/mL and 0.05 mg/mL. 3-CCA and control solutions (PBS only) were loaded in black bottom 96-well plates. Crystal violet and control solutions were loaded in clear bottom 96-well plates. The prepared solutions were irradiated at 2 Gy using a small animal radiation research platform. Fluorescence reading with 360 nm excitation wavelength and 485 nm emission wavelength was done for 3-CCA, and absorbance reading at wavelength 580 nm was done for crystal violet before and after radiation. Results: 3-CCA showed clear difference in fluorescence before and after radiation, which suggested hydroxyl production during radiation. However, crystal violet absorbance at 580 nm was not changed significantly bymore » radiation. Conclusion: The overall conclusion is that 3-CCA can be used for hydroxyl measurement in radiolized water systems, while crystal violet cannot, although crystal violet is reported widely to react with hydroxyl radicals produced in Fenton reactions. Possible reasons could relate to reaction pH.« less

Authors:
;  [1];  [2]; ;  [1]
  1. University of Massachusetts Lowell, Lowell, MA (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22649231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; CRYSTALS; DNA DAMAGES; FLUORESCENCE; HYDROXIDES; HYDROXYL RADICALS; LEAD SULFIDES; MATHEMATICAL SOLUTIONS; PH VALUE; RADIATION CHEMISTRY; WATER; WAVELENGTHS

Citation Formats

Ouyang, Z, Ngwa, W, Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, Strack, G, and Sajo, E. SU-F-T-676: Measurement of Hydroxyl Radicals in Radiolized Water Systems. United States: N. p., 2016. Web. doi:10.1118/1.4956862.
Ouyang, Z, Ngwa, W, Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, Strack, G, & Sajo, E. SU-F-T-676: Measurement of Hydroxyl Radicals in Radiolized Water Systems. United States. doi:10.1118/1.4956862.
Ouyang, Z, Ngwa, W, Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, Strack, G, and Sajo, E. 2016. "SU-F-T-676: Measurement of Hydroxyl Radicals in Radiolized Water Systems". United States. doi:10.1118/1.4956862.
@article{osti_22649231,
title = {SU-F-T-676: Measurement of Hydroxyl Radicals in Radiolized Water Systems},
author = {Ouyang, Z and Ngwa, W and Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA and Strack, G and Sajo, E},
abstractNote = {Purpose: Hydroxyl radicals can be produced within tissue by radiation therapy, and they are largely responsible for DNA damage and cell killing. Coumarin-3-carboxylic acid (3-CCA) and crystal violet are reported to react with hydroxyl radicals and can be used for fluorescence and absorbance measurements, respectively. This study assesses the ability of hydroxyl measurement for both 3-CCA and crystal violet in radiolized water systems in order to provide dosimetric information in radiation chemistry and radiation biology experiments. Methods: 3-CCA and crystal violet were both dissolved in phosphate buffered saline (PBS, pH 7.4) with final concentrations 0.5 mg/mL and 0.05 mg/mL. 3-CCA and control solutions (PBS only) were loaded in black bottom 96-well plates. Crystal violet and control solutions were loaded in clear bottom 96-well plates. The prepared solutions were irradiated at 2 Gy using a small animal radiation research platform. Fluorescence reading with 360 nm excitation wavelength and 485 nm emission wavelength was done for 3-CCA, and absorbance reading at wavelength 580 nm was done for crystal violet before and after radiation. Results: 3-CCA showed clear difference in fluorescence before and after radiation, which suggested hydroxyl production during radiation. However, crystal violet absorbance at 580 nm was not changed significantly by radiation. Conclusion: The overall conclusion is that 3-CCA can be used for hydroxyl measurement in radiolized water systems, while crystal violet cannot, although crystal violet is reported widely to react with hydroxyl radicals produced in Fenton reactions. Possible reasons could relate to reaction pH.},
doi = {10.1118/1.4956862},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}
  • Hydroxyl radicals are the main oxidants formed in the decomposition of ozone in water. This is demonstrated by measuring the relative rates at which different substrates are consumed and comparing them with known reaction rate constants. Knowledge accumulated by radiation chemists and biologists on the reactions of hydroxyl radicals can therefore be used to describe oxidations succeeding ozone decomposition. 8 references, 1 figure, 1 table.
  • The reaction of water and oxygen to form hydroxyl radicals over the metal oxide catalysts La{sub 2}O{sub 3}, Nd{sub 2}O{sub 3}, Sm{sub 2}O{sub 3}, Yb{sub 2}O{sub 3}, CeO{sub 2}, and MgO was studied at pressures up to several Torr. After reaction over 27 mg of La{sub 2}O{sub 3} at 900{degree}C, the measured concentration of hydroxyl radicals in the gas phase, detected by laser induced fluorescence spectroscopy, was equivalent to the expected equilibrium concentration. The reaction becomes kinetically controlled at catalyst loadings below 5 mg. Oxygen incorporation at the surface sites may be the rate limiting step in the catalytic cycle.more » The activities of the catalysts decrease from La{sub 2}O{sub 3}, the most active, to CeO{sub 2}, which is inactive under these reaction conditions. This order is the same as that found for methyl radical formation over these oxides, suggesting that the active site on the catalyst surface is the same for both hydroxyl radical formation and methyl radical formation. 40 refs., 7 figs., 2 tabs.« less
  • The rate constants for the reactions of nitrobenzene with the hydroxyl radical (OH{sup {sm_bullet}}) and hydrated electron ((e{sup -}){sub aq}) in water have been measured from room temperature to 400 {sup o}C using electron pulse radiolysis and transient absorption spectroscopy. The diffusion-limited reaction of nitrobenzene with (e{sup 0}){sub aq} exhibits temperature-insensitive activation energy up to 300 {sup o}C, indicating that the activation energy for electron diffusion remains high over this range. The (e{sup -}){sub aq} reactivity is explained as a long-range electron transfer, and the results are interpreted in terms of extended Marcus theory and Smoluchowski relationships. At 380 {supmore » o}C, the rate constant has a density dependence similar to that previously reported for other (e{sup -}){sub aq} scavenging reactions. The reaction rate of nitrobenzene with OH{sup {sm_bullet}} is very insensitive to temperature from room temperature up to 300 {sup o}C, in agreement with previous studies. Above 300 {sup o}C, the rate constant increases as the critical temperature is approached and exceeded. Time-resolved electronic absorption spectra of the nitrobenzene radiolysis transients reveal complex kinetics involving multiple absorbing species.« less