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

Thomas

Photochem & Photobiology

et al. 2018

Self Cite

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. In solution, the triplet states of these pyranoflavylium cations are efficiently quenched by molecular oxygen, resulting in sensitized formation of singlet oxygen, as confirmed by direct detection of the triplet-state decay by laser flash photolysis and of singlet oxygen monomol emission in the near infrared. The strong visible light absorption, the relatively small singlet-triplet energy differences, the excited state redox potentials and the reasonably long lifetimes of pyranoflavylium triplet states in the absence of molecular oxygen suggest that they might be useful as triplet sensitizers and/or as cationic redox initiators in polar aprotic solvents like acetonitrile.

Section: Methodsmentioning

confidence: 99%

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

Thomas

Photochem & Photobiology

et al. 2018

Self Cite

Journal of Biophotonics

“…Most recently, Michael et al. demonstrated that appropriate model systems are required to interpret the complex 1 O 2 luminescence kinetics obtained from in vivo tumor tissue under PDT‐relevant conditions . An additional concern raised by Foster and colleagues was that measurements of 1 O 2 that are averaged over a finite tissue volume, as in the SOLD technique, overlook the fact that the PS (and hence the 1 O 2 generation) may be highly localized at a microscopic scale and that this can dominate the biological response.…”

Section: O2 Detection Techniquesmentioning

confidence: 99%

“…Significant differences in 1 O 2 luminescence kinetics were observed under the excitation with various pulse widths of nanosecond, microsecond and CW irradiation with the same power of 20 mW. Despite these complications and caveats, SOLD remains a valuable reference technique for 1 O 2 measurements both i n vitro and in vivo as long as care is taken in interpreting the data .…”

Section: O2 Detection Techniquesmentioning

confidence: 99%

Photosensitized singlet oxygen generation and detection: Recent advances and future perspectives in cancer photodynamic therapy

Lin

et al. 2016

163

122

Photodynamic therapy (PDT) uses photosensitizers and visible light in combination with molecular oxygen to produce reactive oxygen species (ROS) that kill malignant cells by apoptosis and/or necrosis, shut down the tumor microvasculature and stimulate the host immune system. The excited singlet state of oxygen ( 1 O 2 ) is recognized to be the main cytotoxic ROS generated during PDT for the majority of photosensitizers used clinically and for many investigational new agents, so that maximizing its production within tumor cells and tissues can improve the therapeutic response, and several emerging and novel approaches for this are summarized. Quantitative techniques for 1 O 2 production measurement during photosensitization are also of immense importance of value for both preclinical research and future clinical practice. In this review, emerging strategies for enhanced photosensitized 1 O 2 generation are introduced, while recent advances in direct detection and imaging of 1 O 2 luminescence are summarized. In addition, the correlation between cumulative 1 O 2 luminescence and PDT efficiency will be highlighted. Meanwhile, the validation of 1 O 2 luminescence dosimetry for PDT application is also considered. This review concludes with a discussion on future demands of 1 O 2 luminescence detection for PDT dosimetry, with particular emphasis on clinical translation.Eye-catching color image for graphical abstract.

Photochem & Photobiology

“…A dual wavelength emission (630 and 405 nm) LED device has been employed for the PDT of skin and hair follicles; the longer wavelength is used to reach the desired target (the sebaceous glands), while the blue emission is employed to photobleach and thereby remove residual amounts of sensitizer, minimizing post‐treatment photosensitivity . Pulsed lasers are also commonly used in the PDT field .…”

Section: Light Deliverymentioning

confidence: 99%

Targeting Photochemical Scalpels or Lancets in the Photodynamic Therapy Field—The Photochemist's Role

Protti

Albini

Viswanathan

et al. 2017

This review covers photochemical approaches aimed at supplementing surgical instruments with handheld photodynamic therapy (PDT) instruments. PDT is not widely used in hospitals, because of the laser equipment and expertise needed, and because insurance policies often do not cover the procedure. Accordingly, this review focuses on advances in photochemistry, photophysics, nanotechnology and miniaturization techniques that may likely inspire the use of handheld instruments in PDT. A takeaway point is that the advent of photochemical scalpels or lancets that deliver reactive oxygen species (ROS) on site may better equip medical practitioners and allow for eradication of tumors or infections in general. Specifically, the review is divided into several sections: sensitizer types, multiphoton and plasmonic topics, sensitizer delivery, light delivery, dosimetry, fiber optics and handheld implements in PDT.