Time-resolved measurements of singlet oxygen dimol-sensitized luminescence

1993 ◽  
Vol 115 (14) ◽  
pp. 6013-6016 ◽  
Author(s):  
Alexander A. Krasnovsky ◽  
Christopher S. Foote
Keyword(s):  
Singlet Oxygen ◽  
Time Resolved ◽  
Sensitized Luminescence ◽  
Time Resolved Measurements

scholarly journals Photophysical Properties of Protoporphyrin IX, Pyropheophorbide-a, and Photofrin® in Different Conditions

2021 ◽  
Vol 14 (2) ◽  
pp. 138
Author(s):  
Bauyrzhan Myrzakhmetov ◽  
Philippe Arnoux ◽  
Serge Mordon ◽  
Samir Acherar ◽  
Irina Tsoy ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Protoporphyrin Ix ◽  
Fluorescence Emission ◽  
Solvent Polarity ◽  
Visible Absorption ◽  
Light Dosimetry ◽  
Time Resolved ◽  
Pyropheophorbide A ◽  
Influence Of Solvent

Photodynamic therapy (PDT) is an innovative treatment of malignant or diseased tissues. The effectiveness of PDT depends on light dosimetry, oxygen availability, and properties of the photosensitizer (PS). Depending on the medium, photophysical properties of the PS can change leading to increase or decrease in fluorescence emission and formation of reactive oxygen species (ROS) especially singlet oxygen (1O2). In this study, the influence of solvent polarity, viscosity, concentration, temperature, and pH medium on the photophysical properties of protoporphyrin IX, pyropheophorbide-a, and Photofrin® were investigated by UV-visible absorption, fluorescence emission, singlet oxygen emission, and time-resolved fluorescence spectroscopies.

scholarly journals Photoreactivity of Hair Melanin from Different Skin Phototypes—Contribution of Melanin Subunits to the Pigments Photoreactive Properties

2021 ◽  
Vol 22 (9) ◽  
pp. 4465
Author(s):  
Krystian Mokrzynski ◽  
Shosuke Ito ◽  
Kazumasa Wakamatsu ◽  
Theodore G. Camenish ◽  
Tadeusz Sarna ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Singlet Oxygen ◽  
Near Infrared ◽  
Paramagnetic Resonance ◽  
Time Resolved ◽  
W Band ◽  
Epr Oximetry ◽  
X Band ◽  
Hair Samples ◽  
Electron Paramagnetic

Photoreactivity of melanin has become a major focus of research due to the postulated involvement of the pigment in UVA-induced melanoma. However, most of the hitherto studies were carried out using synthetic melanin models. Thus, photoreactivity of natural melanins is yet to be systematically analyzed. Here, we examined the photoreactive properties of natural melanins isolated from hair samples obtained from donors of different skin phototypes (I, II, III, and V). X-band and W-band electron paramagnetic resonance (EPR) spectroscopy was used to examine the paramagnetic properties of the pigments. Alkaline hydrogen peroxide degradation and hydroiodic acid hydrolysis were used to determine the chemical composition of the melanins. EPR oximetry and spin trapping were used to examine the oxygen photoconsumption and photo-induced formation of superoxide anion, and time-resolved near infrared phosphorescence was employed to determine the singlet oxygen photogeneration by the melanins. The efficiency of superoxide and singlet oxygen photogeneration was related to the chemical composition of the studied melanins. Melanins from blond and chestnut hair (phototypes II and III) exhibited highest photoreactivity of all examined pigments. Moreover, melanins of these phototypes showed highest quantum efficiency of singlet oxygen photogeneration at 332 nm and 365 nm supporting the postulate of the pigment contribution in UVA-induced melanoma.

Time-resolved measurements of sodium emission in the plume generated by laser ablation of myocardium tissue

2004 ◽  
Author(s):  
Hanriete P. de Souza ◽  
Egberto Munin ◽  
Carlos Eduardo de Vilhena Paiva ◽  
Leandro P. Alves ◽  
Marcela L. Redigolo ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Time Resolved ◽  
Time Resolved Measurements
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