title: The study of the characteristic of photocytotoxicity under high peak power pulsed irradiation with ATX-S10Na(II) in vitro.
abstract: We studied hydrophilic photosensitizer ATX-S10Na(II) mediated photocytotoxicity against macrophage-like cell under pulsed irradiation. We found that photocytotoxicity suppression under high intensity irradiation was directly induced by a decrease in the Type-II photoreaction. We showed that this decrease was not attributable to absorption saturation with the high intensity irradiation. We found the cell lethality change from 70% to 13% with the pulse peak power density ranging from 0.29 MW/cm(2) to 1.36 MW/cm(2), at the light dose of 20 J/cm(2) and the pulse repetition rate at 40 Hz. To investigate the Type-II reaction, we measured the photobleaching, oxygen consumption and singlet oxygen luminescence of the photosensitizer solution. The transient absorption from the photosensitizer during the irradiation was measured with the pump-and-probe technique. We believe that the photocytotoxicity suppression induced by the high intensity irradiation might be useful for the treatment of depth-controlled photodynamic therapy without the wall damage of a hollow organ.
authors: School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan. ohmori@arai.appi.keio.ac.jp
authors: Sayaka
authors: S
authors: Ohmori
authors: Kensuke
authors: K
authors: Masuda
authors: Masatake
authors: M
authors: Yoshida
authors: Tsunenori
authors: T
authors: Arai
authors: Susumu
authors: S
authors: Nakajima
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D008163:Luminescent Measurements; D008264:Macrophages / Q000187:drug effects / Q000528:radiation effects*; D051379:Mice; D010101:Oxygen Consumption / Q000187:drug effects / Q000528:radiation effects; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry / Q000494:pharmacology*; D011166:Porphyrins / Q000737:chemistry / Q000494:pharmacology*; D026082:Singlet Oxygen / Q000528:radiation effects; D013053:Spectrophotometry
chemical_list: C117772:ATX S10Na(II); D017319:Photosensitizing Agents; D011166:Porphyrins; D026082:Singlet Oxygen