Light Dose and Time Dependency of Photodynamic Cell Membrane Damage

Takashi Saito, Nick A. Hartell, Hitoshi Muguruma, Shu Hotta, Satoshi Sasaki, Masao Ito, Isao Karube

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


We have investigated the light dose and time dependency of photodynamic cell membrane damage using electrophysiological methods. This study controls the level of cell membrane damage by precisely administration of the light dose. The photosensitizer used was 5′,5″-bis(aminomethyl)-2,2′:5′,2″-terthiophene dihydrochloride (BAT). A confocal laser scanning microscope was used to provide rapid light activation (<1 s) and the subsequent membrane damage was monitored using standard patch clamp techniques. In the presence of 49 μM BAT, light levels less than 0.94 J/cm2 led to a reversible depolarization (∼20 mV) and reduction of resistance (∼10%) within 3 s of illumination. Higher intensities of illumination (>1.57 J/cm2) caused a complete and irreversible loss of membrane potential and cell membrane resistance within 8 s of illumination. The threshold dose of light required to induce cell death by illumination in the presence of BAT was increased in the presence of the antioxidant Trolox-C.

Original languageEnglish
Pages (from-to)745-748
Number of pages4
JournalPhotochemistry and Photobiology
Issue number5
Publication statusPublished - 1998 Nov
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry


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