Reevaluation of analytical methods for photogenerated singlet oxygen

Keisuke Nakamura, Kirika Ishiyama, Hiroyo Ikai, Taro Kanno, Keiichi Sasaki, Yoshimi Niwano, Masahiro Kohno

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)

Abstract

The aim of the present study is to compare different analytical methods for singlet oxygen and to discuss an appropriate way to evaluate the yield of singlet oxygen photogenerated from photosensitizers. Singlet oxygen photogenerated from rose bengal was evaluated by electron spin resonance analysis using sterically hindered amines, spectrophotometric analysis of 1,3-diphenylisobenzofuran oxidation, and analysis of fluorescent probe (Singlet Oxygen Sensor Green®). All of the analytical methods could evaluate the relative yield of singlet oxygen. The sensitivity of the analytical methods was 1,3-diphenylisobenzofuran < electron spin resonance < Singlet Oxygen Sensor Green®. However, Singlet Oxygen Sensor Green® could be used only when the concentration of rose bengal was very low (<1 μM). In addition, since the absorption spectra of 1,3-diphenylisobenzofuran is considerably changed by irradiation of 405 nm laser, photosensitizers which are excited by light with a wavelength of around 400 nm such as hematoporphyrin cannot be used in the 1,3-diphenylisobenzofuran oxidation method. On the other hand, electron spin resonance analysis using a sterically hindered amine, especially 2,2,6,6-tetramethyl-4-piperidinol and 2,2,5,5-tetramethyl-3-pyrroline-3- carboxamide, had proper sensitivity and wide detectable range for the yield of photogenerated singlet oxygen. Therefore, in photodynamic therapy, it is suggested that the relative yield of singlet oxygen generated by various photosensitizers can be evaluated properly by electron spin resonance analysis.

Original languageEnglish
Pages (from-to)87-95
Number of pages9
JournalJournal of Clinical Biochemistry and Nutrition
Volume49
Issue number2
DOIs
Publication statusPublished - 2011 Sep

Keywords

  • DPIBF
  • Electron spin resonance
  • Fluorescent probe
  • Rose bengal
  • Singlet oxygen

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics
  • Clinical Biochemistry

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