Near infrared multiphoton-induced generation and detection of hydroxyl radicals in a biochemical system

Botchway, SW, Crisostomo, AG, Parker, AW and Bisby, RH 2007, 'Near infrared multiphoton-induced generation and detection of hydroxyl radicals in a biochemical system' , Archives of Biochemistry and Biophysics, 464 (2) , pp. 314-321.

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Solutions of tryptophan and N-hydroxypyridine-2-thione (mercaptopyridine-N-oxide, MPNO) were irradiated at 335 nm. Formation of 5-hydroxytryptophan was inferred from increased fluorescence at 334 nm on excitation at 315 nm, conditions chosen for selective detection of 5 hydroxytryptophan. Such experiments are complicated by overlapping absorption spectra in the region of 300-350 nm. Similar solutions were exposed to multiphoton excitation at 750 nm using 180 fs pulses from a titanium:sapphire laser. In solutions containing both tryptophan and MPNO strong emission at 500 nm was observed that was absent in solutions containing either MPNO or tryptophan only. This emission is ascribed to the characteristic fluorescence (‘hyperluminescence’) from 5-hydroxyindoles resulting from multiphoton photochemistry. The conclusion that MPNO generates hydroxyl radicals by 2 photon activation at 750 nm is confirmed by the scavenging effects of ethanol and kinetic analysis of the results. This method has potential applications in intracellular induction of oxidative stress using multiphoton near-infrared illumination, a technology that is gaining momentum as a research tool.

Item Type: Article
Uncontrolled Keywords: Radical, hydroxyl, scavenging, multiphoton, microscopy, mercaptopyridine-n-oxide, photofenton, spectroscopy, laser, femtosecond
Themes: Subjects / Themes > Q Science > QD Chemistry
Subjects outside of the University Themes
Schools: Schools > School of Environment and Life Sciences
Schools > School of Environment and Life Sciences > Biomedical Research Centre
Journal or Publication Title: Archives of Biochemistry and Biophysics
Publisher: Elsevier
Refereed: Yes
ISSN: 00039861
Related URLs:
Depositing User: RH Bisby
Date Deposited: 24 Jun 2009 11:15
Last Modified: 14 Oct 2019 10:48

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