Reactive oxygen species produced upon photoexcitation of sunscreens containing titanium dioxide (an EPR study)

Brezová, Vlasta; Gabcova, Sofia; Dvoranová, Dana; Staško, Andrej

doi:10.1016/j.jphotobiol.2004.12.006

Cited by 183 publications

(112 citation statements)

References 55 publications

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“…6b). These results suggest that at pH 9 the degradation when these methyl radicals react with oxygen [26]. As expected at pH 3, no formation of CO2 has been detected by ATR-FTIR spectroscopy (Fig.…”

Section: Discussionsupporting

confidence: 78%

Pathways of the photocatalytic reaction of acetate in H2O and D2O: A combined EPR and ATR-FTIR study

Belhadj

Melchers

Robertson

et al. 2016

Journal of Catalysis

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The adsorption and photocatalytic degradation of acetate on TiO2 surfaces was investigated in H2O and D2O by ATR-FTIR and EPR Spectroscopy respectively. These studies were carried out in the dark and under UV(A) illumination to gain additional insights into the adsorption behaviour with the identification of paramagnetic species formed during the oxidation of acetate. Isotopic exchange during the adsorption of D2O on TiO2 surface led to different interactions between the adsorbate and OD groups. At different pH levels, several surface complexes of acetate can be formed such as monodentate, or bidentates. Under UV(A) irradiation of TiO2 aqueous suspensions, the formation of hydroxyl and methoxy radicals evidenced as the corresponding spin-adducts, were found to dominate in alkaline and acidic suspensions respectively. Two possible pathways for the oxidation of acetate have been suggested at different pH levels in solution in terms of the source of the spin adduct formed.These proposed pathways were found to be in good agreement with ATR-FTIR and EPR results.

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Section: Discussionsupporting

confidence: 78%

Pathways of the photocatalytic reaction of acetate in H2O and D2O: A combined EPR and ATR-FTIR study

Belhadj

Melchers

Robertson

et al. 2016

Journal of Catalysis

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“…Being diamagnetic, this species is not detected by EPR. However, 1 O 2 may react with the spin probe 4-oxo-TMP to give a nitroxide radical as previously reported by other authors (Konaka et al 1999;Brezova et al 2005). By irradiation of the pristine powder in the presence of spin probe, a threeline signal typical of the nitroxide radical was obtained (Fig.…”

Section: Generation Of Singlet Oxygensupporting

confidence: 76%

“…Therefore, commercial nano-TiO 2 are generally coated with inert materials (Lee et al 2007;Landsiedel et al 2010) which inhibits the formation of radical species and singlet oxygen by preventing the contact of the TiO 2 surface with oxygen and water. However, not all the coatings are equally efficient in preventing the release of surface-derived ROS (Sayes et al 2006;Brezova et al 2005;Carlotti et al 2009;Tiano et al 2010;Buchalska et al 2010). Antioxidant ingredients are also added to the formula to mitigate the oxidative properties of photogenerated ROS (Carlotti et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Inhibition of the ROS-mediated cytotoxicity and genotoxicity of nano-TiO2 toward human keratinocyte cells by iron doping

et al. 2014

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Inhibition of the ROS-mediated cytotoxicity and genotoxicity of nano-TiO 2 toward human keratinocyte cells by iron doping J Nanopart Res (2014) Nano-TiO 2 powders are widely used in sunscreen lotions as UV filters in combination with other substances. The activation of TiO 2 by UV rays leads to the release of reactive oxygen species (ROS, e.g., hydroxyl radicals and singlet oxygen) which are potentially harmful. For this reason the TiO 2 particles are generally coated with inert materials (e.g., silica or alumina) that inhibit such reactivity. Alternatively, the release of ROS may be inhibited by introducing in the TiO 2 lattice doping elements. In the present study we report a new modification consisting in a wet impregnation of TiO 2 with iron salts followed by a thermal treatment that results in an inhibition of the surface reactivity. The insertion of iron ions also gradually reduces the ability of photo-activated TiO 2 to cleave DNA and proteins. At the same time, a clear inhibition of cyto-and geno-toxicity toward human (HaCaT) keratinocytes was observed. The data presented herein suggest the insertion of Fe 3+ ions at the surface of nano-TiO 2 as a promising strategy to reduce the photo-induced toxicity of nano-TiO 2 powders.

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“…Moreover, nanoparticles of zinc and titanium oxides possess enormous photocatalytic activity [4], thus inducing the increase in their toxicity upon irradiation. Reactive oxygen species (ROS) forming during photocatalytic processes decompose not only components of cosmetics but even skincells [5,6]. It was demonstrated that under UV-irradiation TiO 2 and ZnO nanoparticles being the part of sunscreen cosmetics generate hydroxyl radicals [7,8] damaging DNA of skin cells [9].…”

Section: Introductionmentioning

confidence: 99%

Nanostructured ceria synthesized by detonation method and its ultraviolet absorption performance

Zhao¹,

Xie²,

Han³

et al. 2013

WIT Transactions on Engineering Sciences

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Nanostructured ceria particles have been successfully synthesized by detonation method with emulsion explosives. The effects of mass content of Ce(NO 3 ) 3 ·6H 2 O in emulsion explosives on particle size of CeO 2 were investigated. X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) were carried out to characterize as-synthesized powders. The ultraviolet absorption performance of nanostructured ceria was tested by ultraviolet spectrophotometer. The results indicated that the mass content of Ce(NO 3 ) 3 ·6H 2 O in emulsion explosives affected the particle size of ceria mostly. When the mass content of Ce(NO 3 ) 3 ·6H 2 O was 53.2%, the particle size of ceria was even and on the small side. The UV absorption performance of assynthesized nanostructured ceria was excellent, especially for ultraviolet B.

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Reactive oxygen species produced upon photoexcitation of sunscreens containing titanium dioxide (an EPR study)

Cited by 183 publications

References 55 publications

Pathways of the photocatalytic reaction of acetate in H2O and D2O: A combined EPR and ATR-FTIR study

Pathways of the photocatalytic reaction of acetate in H2O and D2O: A combined EPR and ATR-FTIR study

Inhibition of the ROS-mediated cytotoxicity and genotoxicity of nano-TiO2 toward human keratinocyte cells by iron doping

Nanostructured ceria synthesized by detonation method and its ultraviolet absorption performance

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