Photobleaching Efficiency Parallels the Enhancement of Membrane Damage for Porphyrazine Photosensitizers.

Photostability is considered a key asset for photosensitizers (PS) used in medical applications as well as for those used in energy conversion devices. In light-mediated medical treatments, which are based on PS-induced harm to diseased tissues, the photoinduced cycle of singlet oxygen generation has always been considered to correlate with PS efficiency. However, recent evidence points to the fundamental role of contact-dependent reactions, which usually cause PS photobleaching.

Triplet Excited States and Singlet Oxygen Production by Analogs of Red Wine Pyranoanthocyanins.

During the maturation of red wines, the anthocyanins of grapes are transformed into pyranoanthocyanins, which possess a pyranoflavylium cation as their basic chromophore. Photophysical properties of the singlet and triplet excited states of a series of synthetic pyranoflavylium cations were determined at room temperature in acetonitrile solution acidified with 0.10 mol dm trifluoroacetic acid (TFA, to inhibit competitive excited state proton transfer) and at 77 K in a rigid TFA-acidified isopropanol glass.

Prospects of in vivo singlet oxygen luminescence monitoring: Kinetics at different locations on living mice.

Background: Singlet oxygen observation is considered a valuable tool to assess and optimize PDT treatment. In complex systems, such as tumors in vivo, only the direct, time-resolved singlet oxygen luminescence detection can give reliable information about generation and interaction of singlet oxygen. Up to now, evaluation of kinetics was not possible due to insufficient signal-to-noise ratio.

Luminescence investigation of photosensitizer distribution in skin: correlation of singlet oxygen kinetics with the microarchitecture of the epidermis.

This is the first study showing that singlet oxygen kinetics of topically applied photosensitizers coincides with the microarchitecture of skin, e.g., fissures and hair follicles.

Time-resolved singlet oxygen luminescence detection under photodynamic therapy relevant conditions: comparison of ex vivo application of two photosensitizer formulations.

Singlet oxygen plays a crucial role in photo-dermatology and photodynamic therapy (PDT) of cancer. Its direct observation by measuring the phosphorescence at 1270 nm, however, is still challenging due to the very low emission probability. It is especially challenging for the time-resolved detection of singlet oxygen kinetics in vivo which is of special interest for biomedical applications.