scholarly journals EPR spectroscopy investigation of oxygen radical production by methylene blue and indocyanine green in aqueous solutions under laser irradiation in the context of antibacterial photodynamic therapy

Folia Medica ◽  
2021 ◽  
Vol 63 (3) ◽  
pp. 372-376
Author(s):  
Mihail Tanev ◽  
Georgi Tomov ◽  
Yordanka Karakirova
Keyword(s):  
Reactive Oxygen Species ◽  
Methylene Blue ◽  
Photodynamic Therapy ◽  
Aqueous Solutions ◽  
Epr Spectroscopy ◽  
Reactive Oxygen ◽  
Spin Trapping ◽  
Oxygen Radical ◽  
Oxygen Species ◽  
Radical Production

Introduction: Antibacterial photodynamic therapy is a promising treatment modality in the anti-infective therapy of numerous oral diseases. It involves photo activation of a reactive substance (dye), thus releasing reactive oxygen species (ROS-radicals) which are highly destructive to the bacterial cell. However, thorough investigation of radical production properties of different dyes is not common in literature. Aim: The aim of this study was to investigate and evaluate oxygen radical-producing potential of two commonly used photoactive dyes in the context of antibacterial photodynamic therapy. Materials and methods: The radical-producing properties of two commonly used dyes for photodynamic therapy in oral medicine, methylene blue and indocyanine green, irradiated under laser irradiation are investigated using electron paramagnetic resonance (EPR) spectroscopy. The detection of reactive oxygen species is performed with “spin-trapping” technique. Results: The selected photoactive dyes showed promising yields of reactive oxygen species (ROS) in aqueous solutions. The comparative analysis of the results deemed methylene blue as the more productive photoactive agent. Conclusions: By employing the spin-trapping technique, this study indicates EPR-spectroscopy as a promising method of relative quantification of reactive oxygen species released by the photodynamic reaction in aqueous solutions.

Photoassisted Production of O2-• and H2 in Aqueous Medium Stimulated by Polythiophene in ZSM-5 Zeolite Channels

1999 ◽  
Vol 64 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Gabriel Čík ◽  
František Šeršeň ◽  
Alena Bumbálová
Keyword(s):  
Reactive Oxygen Species ◽  
Ion Exchange ◽  
Visible Light ◽  
Aqueous Medium ◽  
Exchange Reaction ◽  
Epr Spectroscopy ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Water Reduction ◽  
Ion Exchange Reaction

The formation of reactive oxygen species due to irradiation by a visible light of the polythiophene deposited in ZSM-5 zeolite channels in aqueous medium has been studied. Polymerization of thiophene was carried out in zeolite channels after the ion-exchange reaction of Na+ for Fe3+. By means of EPR spectroscopy, the temporarily generated 1O2 in irradiated aqueous medium was proved. The formation of O2-• was confirmed by the reduction of Fe3+-cytochrome c. Irradiation led to the water reduction to hydrogen.

Photocatalytic Degradation of 4-Chlorophenol by •OH Radicals Generated by Thiophene Oligomers Incorporated in ZSM-5 Zeolite Channels

2003 ◽  
Vol 68 (11) ◽  
pp. 2219-2230 ◽  
Author(s):  
Gabriel Čík ◽  
Milada Hubinová ◽  
František Šeršeň ◽  
Jozef Krištín ◽  
Monika Antošová
Keyword(s):  
Reactive Oxygen Species ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Maleic Acid ◽  
Aqueous Suspension ◽  
Reactive Oxygen ◽  
Spin Trapping ◽  
Oh Radicals ◽  
Oxygen Species ◽  
Trapping Method

Degradation of 4-chlorophenol by reactive oxygen species was studied, the latter being generated by photo-assisted reactions of thiophene oligomers, synthesized in channels of the Na-ZSM-5 zeolite. The photoreaction was carried out in an aqueous suspension of photocatalyst, irradiated with visible light (λ > 400 nm). The spin-trapping method was used to detect the generated •OH radicals. The main products of the photodecomposition of 4-chlorophenol were found to be phenol, hydroquinone and maleic acid.

scholarly journals Rare-Earth-Doped Calcium Carbonate Exposed to X-ray Irradiation to Induce Reactive Oxygen Species for Tumor Treatment

2019 ◽  
Vol 20 (5) ◽  
pp. 1148 ◽  
Author(s):  
Chun-Chen Yang ◽  
Wei-Yun Wang ◽  
Feng-Huei Lin ◽  
Chun-Han Hou
Keyword(s):  
Reactive Oxygen Species ◽  
Photodynamic Therapy ◽  
Tumor Growth ◽  
Light Source ◽  
Reactive Oxygen ◽  
Blood Analysis ◽  
Oxygen Species ◽  
Tumor Treatment ◽  
X Ray

Conventional photodynamic therapy (PDT) is limited by its penetration depth due to the photosensitizer and light source. In this study, we developed X-ray induced photodynamic therapy that applied X-ray as the light source to activate Ce-doped CaCO3 (CaCO3:Ce) to generate an intracellular reactive oxygen species (ROS) for killing cancer cells. The A549 cell line was used as the in vitro and in vivo model to evaluate the efficacy of X-ray-induced CaCO3:Ce. The cell viability significantly decreased and cell cytotoxicity obviously increased with CaCO3:Ce exposure under X-ray irradiation, which is less harmful than radiotherapy in tumor treatment. CaCO3:Ce produced significant ROS under X-ray irradiation and promoted A549 cancer cell death. CaCO3:Ce can enhance the efficacy of X-ray induced PDT, and tumor growth was inhibited in vivo. The blood analysis and hematoxylin and eosin stain (H&E) stain fully supported the safety of the treatment. The mechanisms underlying ROS and CO2 generation by CaCO3:Ce activated by X-ray irradiation to induce cell toxicity, thereby inhibiting tumor growth, is discussed. These findings and advances are of great importance in providing a novel therapeutic approach as an alternative tumor treatment.

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