Search results for "singlet oxygen"
showing 10 items of 62 documents
Synthesis and In Vitro Evaluation of a Photosensitizer-BODIPY Derivative for Potential Photodynamic Therapy Applications
2015
A new photosensitizer (1) based on the 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) scaffold has been synthesized. 1 is water soluble and showed an intense absorption band at 490 nm (e=77600 cm-1M-1) and an emission at 514 nm. In vitro toxicity of 1 in the presence of light and in darkness has been studied with HeLa, HaCaT, MCF-7, and SCC-13 cell lines. Moreover, internalization studies of 1 in these cell lines were also performed. These results suggested that 1 is more toxic for SCC-13 and HeLa carcinoma cells than for the HaCaT noncancerous immortal human keratinocytes. Toxicity upon light irradiation was due to the formation of singlet oxygen and reactive oxygen species (ROS). Cel…
Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation
2012
Marine biofouling—the colonization of small marine microorganisms on surfaces that are directly exposed to seawater, such as ships' hulls—is an expensive problem that is currently without an environmentally compatible solution1. Biofouling leads to increased hydrodynamic drag, which, in turn, causes increased fuel consumption and greenhouse gas emissions. Tributyltin-free antifouling coatings and paints1, 2, 3, 4 based on metal complexes or biocides have been shown to efficiently prevent marine biofouling. However, these materials can damage5 the environment through metal leaching (for example, of copper and zinc)6 and bacteria resistance7. Here, we show that vanadium pentoxide nanowires ac…
Wavelength dependence of oxidative DNA damage induced by UV and visible light.
1997
DNA damage induced by UV radiation and visible light (290-500 nm) in AS52 Chinese hamster cells was analysed by an alkaline elution assay with specific repair endonucleases. Cells were exposed to extensively filtered monochrome or broad-band radiation. Between 290 and 315 nm, the ratio of base modifications sensitive to Fpg protein (i.e. 8-hydroxyguanine and formamidopyrimidines) and T4 endonuclease V (i.e. cyclobutane pyrimidine dimers) was constant (approximately 1:200), indicating that the direct excitation of DNA is responsible for both types of damage in this range of the spectrum. While the yield of pyrimidine dimers per unit dose continued to decrease exponentially beyond 315 nm, the…
Synthesis, spectroscopic studies and biological evaluation of acridine derivatives: The role of aggregation on the photodynamic efficiency.
2018
Two new photoactive compounds (1 and 2) derived from the 9-amidoacridine chromophore have been synthesized and fully characterized. Their abilities to produce singlet oxygen upon irradiation have been compared. The synthesized compounds show very different self-aggregating properties since only 1 present a strong tendency to aggregate in water. Biological assays were conducted with two cell types: hepatoma cells (Hep3B) and human umbilical vein endothelial cells (HUVEC). Photodynamic therapy (PDT) studies carried out with Hep3B cells showed that non-aggregating compound 2 showed photoxicity, ascribed to the production of singlet oxygen, being aggregating compound 1 photochemically inactive.…
Cover Picture: Photo-Chromium: Sensitizer for Visible-Light-Induced Oxidative C−H Bond Functionalization-Electron or Energy Transfer? (ChemPhotoChem …
2017
Formation of HXeO in a xenon matrix: Indirect evidence of production, trapping, and mobility of XeO (1 1Σ+) in solid Xe
2004
IR spectroscopy, laser induced fluorescence (LIF), and thermoluminescence (TL) measurements have been combined to monitor trapping, thermal mobility, and reactions of oxygen atoms in solid xenon. HXeO and O(3) have been used as IR active species that probe the reactions of oxygen atoms. N(2)O and H(2)O have been used as precursors for oxygen atoms by photolysis at 193 nm. Upon annealing of matrices after photolysis, ozone forms at two different temperatures: at 18-24 K from close O ...O(2) pairs and at approximately 27 K due to global mobility of oxygen atoms. HXeO forms at approximately 30 K reliably at higher temperature than ozone. Both LIF and TL show activation of oxygen atoms around 3…
Synthesis, structure and biological properties of several binary and ternary complexes of copper(II) with ciprofloxacin and 1,10 phenanthroline
2009
In this study, a new binary complex [Cu(HCip) 2 ](NO 3 ) 2 · 6H 2 O ( 1 ) has been synthesized and then characterized by X-ray structure analyses. In this compound, each ciprofloxacin acts as a bidentate ligand resulting in a crystallographically planar configuration; the nitrate anions are located in apical positions with an axial distance significantly larger than the equatorial distances, which would be consistent with a very weak metal ion interaction due to the Jahn–Teller effect. In addition, both the synthesis and characterization of two new ternary complexes of ciprofloxacin–copper(II)–1,10-phenanthroline, [Cu(phen)(Cip)](NO 3 ) · 4H 2 O ( 2 ) and Cu(phen)(HCip)(NO 3 ) 2 · H 2 O (…
Water-Soluble Chlorophyll Protein (WSCP) Stably Binds Two or Four Chlorophylls
2017
Water-soluble chlorophyll proteins (WSCPs) of class IIa from Brassicaceae form tetrameric complexes containing one chlorophyll (Chl) per apoprotein but no carotenoids. The complexes are remarkably stable toward dissociation and protein denaturation even at 100 °C and extreme pH values, and the Chls are partially protected against photooxidation. There are several hypotheses that explain the biological role of WSCPs, one of them proposing that they function as a scavenger of Chls set free upon plant senescence or pathogen attack. The biochemical properties of WSCP described in this paper are consistent with the protein acting as an efficient and flexible Chl scavenger. At limiting Chl concen…
Biological Evaluation of the NIR-Emissive Ruby Analogue [Cr(ddpd) 2 ][BF 4 ] 3 as a Photodynamic Therapy Photosensitizer
2018
International audience; Photodynamic therapy relies on the bioavailability of photosensitizers with suitable photophysical, chemical and biochemical properties. Although the photophysical properties, stability and high water solubility of the chromium(III) complex [Cr(ddpd)2][BF4]3 (ddpd = N,N'-dimethyl-N,N'-dipyridin-2-ylpyridine-2,6-diamine) are very favorable, its photocytotoxicity against cancerous and non-cancerous cell lines has not yet been elucidated. We now report the cytotoxicity and photocytotoxicity of the complex [Cr(ddpd)2][BF4]3 against human cervical cancer cells, human primary glioblastoma cells, human glioblastoma astrocytoma cells and non-cancerous retinal pigment epithel…