Detection of active oxygen species in a photosensitizing reaction in vitro by ESR measurements

Norio Miyoshi

doi:10.1117/12.203426

1 March 1995 Detection of active oxygen species in a photosensitizing reaction in vitro by ESR measurements

Norio Miyoshi

Author Affiliations +

Proceedings Volume 2371, 5th International Photodynamic Association Biennial Meeting; (1995) https://doi.org/10.1117/12.203426
Event: Fifth International Photodynamic Association Biennial Meeting, 1994, Amelia Island, FL, United States

Abstract

The photodynamic therapy of cancer has been improved by the developments of laser technology and photosensitizers the last 15 years. The relative yield of active oxygen species generated in the photosensitizing reaction was obtained in vitro by photochemical techniques and ESR measurements with spin trapping reagents in order to find an effective photosensitizer. Cethyltrimethyl ammonium bromide (CTAB) micellar aqueous solutions and human melanoma cultivated (HMF) cell suspensions were used for the in vitro experiments. Photosensitizer was incorporated into the CTAB micelles or HMF cells, and 5,5'-dimethyl-1- pyroline-N-oxide (DMPO) and 2,2,6,6-tetramethyl-4-pyperidone hydrochloride (TMPD) were used for the detection of OH, C (type I reaction) and ¹O₂^* (type II reaction), respectively. After irradiation by laser light or by monochromatic light, the ESR spectra were analyzed. It was found that type I reaction was predominant for the aggregate form of the photosensitizer and type II for the monomer form in CTAB micellar solutions. It was suggested that the predominant type II reaction in HMF cell suspension indicated the monomerization of the photosensitizer by the cells also in the case of hematoporphyrin oligomer (HpO).

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Norio Miyoshi "Detection of active oxygen species in a photosensitizing reaction in vitro by ESR measurements", Proc. SPIE 2371, 5th International Photodynamic Association Biennial Meeting, (1 March 1995); https://doi.org/10.1117/12.203426

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