The Excitation Spectra of Singlet Oxygen and Photoluminescence of Methyl Pheophorbide-a
The correlation between the photoluminescence intensity of a dye-sensitizer (methyl pheophorbide-a, MPP-a) and the efficiency of the singlet oxygen (1O2) generation is studied. The excitation spectrum of 1O2 emission at 1270 nm has one strong band at 403 nm that coincides with the Soret band of MPP-a and only a weak peak at 667 nm, which practically coincides with the strongest band of the MPP-a excitation spectrum. Therefore, the choice of an excitation wavelength for the efficient 1O2 generation should be based on direct measurements of the excitation spectra of the sensitized 1O2 emission.
F.C. Pennington, H.H. Strain, and W.A. Svec, J. of the Amer. Chem. Soc. 86, 1418 (1964).
G. Weagle, The Assessment of Pheophorbide a Ethanolamide as a Potential Dual Action Anticancer Photosensitizer (Univ. du Quebec, Trois-Rivieres, 1995), (http://depot-e.uqtr.ca).
S. Hackbarth, E.A. Ermilov, and B. Roder, Optics Commun. 248, 295 (2005).
S. al-Omari, Rom. J. Biophys. 20, 295 2010.
J. Larsen, B. Bruggemann, T. Polivka, V. Sundstrom, E. Akesson, J. Sly and M.J. Crossley, J. of Phys. Chem. A 109, 10654 (2005).
J.S. McCaughan, jr., Drugs Aging 15, 49 (1999).
B.W. Henderson and T.J. Dougherty, Photochem. Photobiol. 55, 145 (1992).
D. Datta, N. Vaidehi, X. Xu, and W.A. Goddard, Proc. Nat. Acad. Sci. USA 99, 2636 (2002).