Degradation of natural toxins by phthalocyanines–example of cyanobacterial toxin, microcystin

2010 ◽  
Vol 62 (2) ◽  
pp. 273-278 ◽  
Author(s):  
Daniel Jančula ◽  
Lucie Bláhová ◽  
Marie Karásková ◽  
Blahoslav Maršálek
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Visible Light ◽  
Singlet Oxygen ◽  
Oxygen Species ◽  
Cyanobacterial Toxin ◽  
Natural Toxins ◽  
Peptide Toxins ◽  
Near Future ◽  
Absorption Characteristics

Phthalocyanines (Pcs) are promising photosensitizers for use in various branches of science and industry. In the presence of visible light and diatomic oxygen, phthalocyanines can react to produce singlet oxygen, a member of reactive oxygen species able to damage different molecules and tissues. The aim of this study was to investigate the ability of phthalocyanines to degrade natural toxins in the presence of visible light. As the representative of hardly degradable toxins, a group of cyanobacterial peptide toxins—microcystin-LR—was chosen for this study. According to our results, phthalocyanines are able to degrade 61,5% of microcystins within a 48-hour incubation (38% of microcystins was degraded after 24 h and 24% after 12 h of incubation). Although other oxidants like hydrogen peroxide or ozone are able to degrade microcystins within several hours, we assume that by optimizing the spectrum emitted by light source and by changing the absorption characteristics of Pcs, microcystins degradation by phthalocyanines could be more effective in the near future.

scholarly journals Photogeneration of reactive oxygen species over ultrafine TiO2 particles functionalized with rutin–ligand induced sensitization and crystallization effects

2019 ◽  
Vol 45 (12) ◽  
pp. 5781-5800 ◽  
Author(s):  
Przemysław Łabuz ◽  
Joanna Gryboś ◽  
Piotr Pietrzyk ◽  
Kamila Sobańska ◽  
Wojciech Macyk ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Charge Transfer ◽  
Visible Light ◽  
Colloidal Stability ◽  
Reactive Oxygen ◽  
Hydroxyl Groups ◽  
Oxygen Species ◽  
Environmental Implications ◽  
Transfer Processes

Abstract Interaction of amorphous and crystalline TiO2 ultrafine particles (2–6 nm) with rutin results in the formation of colored nanomaterials of an excellent dispersity and enhanced colloidal stability in aqueous media. The FTIR and Raman spectra confirmed attachment of the rutin ligand via vicinal hydroxyl groups in a catechol-like fashion. The binding of rutin to amorphous TiO2 gives rise to spontaneous crystallization of the parent nanoparticles into hydrogen titanates (H2Ti3O7 and H2Ti12O25). Such structural transformations result in photosensitization toward visible light with enhanced efficiency of the charge separation and interfacial charge transfer processes, confirmed by detailed photoelectrochemical studies of the examined nanomaterials. The effectiveness of the photocatalytic ROS generation reactions was also strongly influenced by hydrogen peroxide, which plays a double role of a reactant prone to reduction and generation of hydroxyl radicals or a redox agent destroying the intra-band gap electronic states, suppressing thereby charge recombination. The photoinduced charge transfer processes lead to generation of various reactive oxygen species, which were detected by EPR using DMPO spin trap (HOO· detection) and in the reaction with terephthalic acid acting as a chemical scavenger (HO· detection). Complexation of TiO2 particles with rutin shifts the photogeneration of hydroperoxyl (HOO·) and hydroxyl (HO·) radicals toward visible light (λ > 400 nm). A triple effect of rutin attachment to titania was established. It consists in pronounced photosensitization, promotion of crystallization and enhancement of the colloidal stability of ultrafine titania particles. Environmental implications of these assets on the photoinduced redox reactions with hydrogen peroxide in aqueous solutions upon UV or visible light irradiation were also discussed.

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.

scholarly journals Photo-Responsive Supramolecular Micelles for Controlled Drug Release and Improved Chemotherapy

2020 ◽  
Vol 22 (1) ◽  
pp. 154
Author(s):  
Fasih Bintang Ilhami ◽  
Kai-Chen Peng ◽  
Yi-Shiuan Chang ◽  
Yihalem Abebe Alemayehu ◽  
Hsieh-Chih Tsai ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Drug Release ◽  
Visible Light ◽  
Cancer Cells ◽  
Laser Irradiation ◽  
Reactive Oxygen ◽  
Controlled Drug Release ◽  
Grand Challenge ◽  
Supramolecular System ◽  
Oxygen Species

Development of stimuli-responsive supramolecular micelles that enable high levels of well-controlled drug release in cancer cells remains a grand challenge. Here, we encapsulated the antitumor drug doxorubicin (DOX) and pro-photosensitizer 5-aminolevulinic acid (5-ALA) within adenine-functionalized supramolecular micelles (A-PPG), in order to achieve effective drug delivery combined with photo-chemotherapy. The resulting DOX/5-ALA-loaded micelles exhibited excellent light and pH-responsive behavior in aqueous solution and high drug-entrapment stability in serum-rich media. A short duration (1–2 min) of laser irradiation with visible light induced the dissociation of the DOX/5-ALA complexes within the micelles, which disrupted micellular stability and resulted in rapid, immediate release of the physically entrapped drug from the micelles. In addition, in vitro assays of cellular reactive oxygen species generation and cellular internalization confirmed the drug-loaded micelles exhibited significantly enhanced cellular uptake after visible light irradiation, and that the light-triggered disassembly of micellar structures rapidly increased the production of reactive oxygen species within the cells. Importantly, flow cytometric analysis demonstrated that laser irradiation of cancer cells incubated with DOX/5-ALA-loaded A-PPG micelles effectively induced apoptotic cell death via endocytosis. Thus, this newly developed supramolecular system may offer a potential route towards improving the efficacy of synergistic chemotherapeutic approaches for cancer.

Hydrogen peroxide-responsive AIE probe for imaging-guided organelle targeting and photodynamic cancer cell ablation

2021 ◽  
Author(s):  
Qian Wu ◽  
Youmei Li ◽  
Ying Li ◽  
Dong Wang ◽  
Ben Zhong Tang
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Cancer Cell ◽  
Reactive Oxygen ◽  
Living Cells ◽  
Oxygen Species ◽  
Cell Ablation ◽  
Selective Monitoring ◽  
Organelle Targeting

Hydrogen peroxide (H2O2), as one kind of key reactive oxygen species (ROS), is mainly produced endogenously primarily in the mitochondria. The selective monitoring of H2O2 in living cells is of...

scholarly journals Intracellular Sources of ROS/H2O2 in Health and Neurodegeneration: Spotlight on Endoplasmic Reticulum

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 233
Author(s):  
Tasuku Konno ◽  
Eduardo Pinho Melo ◽  
Joseph E. Chambers ◽  
Edward Avezov
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Endoplasmic Reticulum ◽  
Neurodegenerative Diseases ◽  
Antioxidative Enzymes ◽  
Redox Reactions ◽  
Ros Production ◽  
Oxygen Species ◽  
Specific Target

Reactive oxygen species (ROS) are produced continuously throughout the cell as products of various redox reactions. Yet these products function as important signal messengers, acting through oxidation of specific target factors. Whilst excess ROS production has the potential to induce oxidative stress, physiological roles of ROS are supported by a spatiotemporal equilibrium between ROS producers and scavengers such as antioxidative enzymes. In the endoplasmic reticulum (ER), hydrogen peroxide (H2O2), a non-radical ROS, is produced through the process of oxidative folding. Utilisation and dysregulation of H2O2, in particular that generated in the ER, affects not only cellular homeostasis but also the longevity of organisms. ROS dysregulation has been implicated in various pathologies including dementia and other neurodegenerative diseases, sanctioning a field of research that strives to better understand cell-intrinsic ROS production. Here we review the organelle-specific ROS-generating and consuming pathways, providing evidence that the ER is a major contributing source of potentially pathologic ROS.

scholarly journals Upconversion-based nanosystems for fluorescence sensing of pH and H2O2

2021 ◽  
Author(s):  
Chunning Sun ◽  
Michael Gradzielski
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Excitation Energy ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Fluorescence Sensing ◽  
Living Organisms

Hydrogen peroxide (H2O2), a key reactive oxygen species, plays an important role in living organisms, industrial and environmental fields. Here, a non-contact upconversion nanosystem based on the excitation energy attenuation...

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