Journal of Fluorescence

, Volume 14, Issue 1, pp 71–74 | Cite as

Luminescence Study of Singlet Oxygen Production by Meso-Tetraphenylporphine

  • Miloslav Kořinek
  • Roman Dědic
  • Antonin Svoboda
  • Jan Hála

Abstract

The research in the field of the photodynamic therapy of cancer (PDT) is focused on a development of photosensitizers exhibiting high quantum yield of singlet oxygen production. Direct time-resolved spectroscopic observation of singlet oxygen phosphorescence can provide time constants of its population and depopulation as well as photosensitizer phosphorescence lifetime and relative quantum yields. In our contribution, a study of time and spectral resolved phosphorescence of singlet oxygen photosensitized by meso-tetraphenylporphine in acetone together with the photosensitizer phosphorescence is presented. Time constants of singlet oxygen population and depopulation were determined at wide range of photosensitizer concentrations. The time constant of singlet oxygen generation (0.28 ± 0.01) μs is slightly shorter then the lifetime of photosensitizer's triplet state (0.32 ± 0.01) μs. It is caused by lower ability of TPP aggregates to transfer excitation energy to oxygen. The lifetime of singlet oxygen (≈50 μs) decreases with increasing photosensitizer concentration. Therefore, the photosensitizer acts also as a quencher of oxygen singlet state, similarly to the effects observed in [A. A. Krasnovsky, P. Cheng, R. E. Blankenship, T. A. Moore, and D. Gust (1993). Photochem. Photobiol.57, 324–330; H. Küpper, R. Dědic, A. Svoboda, J. Hála, and P. M. H. Kroneck (2002). Biochim. Biophys. Acta Gen. Subj.1572, 107–113]. Moreover, the increasing concentraion of the photosensitizer causes a slight hypsochromic shift of the singlet oxygen luminescence maximum.

TPP singlet oxygen photodynamic therapy photosensitizer 

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Copyright information

© Plenum Publishing Corporation 2004

Authors and Affiliations

  • Miloslav Kořinek
    • 1
  • Roman Dědic
    • 1
  • Antonin Svoboda
    • 1
  • Jan Hála
    • 1
  1. 1.Department of Chemical Physics and Optics, Faculty of Mathematics and PhysicsCharles UniversityCzech Republic

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