UV-TiO2
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The aim of the study was the comparison of photo-activity of three types of titanium dioxide (TiO2) micro-dispersions intended for use as UV filters for cosmetic sunscreen products. The dispersions were also investigated with regard to their influence on the stability of photo-protective systems in cosmetic emulsions, their skin penetration/absorption and their photo-toxicity for humans and skin bacterial flora. All the tested micro-dispersions of rutile TiO2 type (agglomerates with diameter 120-150 nm), with primary particle size lower than 100 nm, demonstrated no phototoxic effect and insignificant antimicrobial behaviour. On the other hand, TiO2 with insufficient deactivation of photo-activity had significant negative impact on the stability of other organic UV filters and therefore on the stability of declared UV protective factors (SPF, UVA-PF). The study demonstrated that the level of deactivation of TiO2 is one of the highly important factors for evaluation of UV filters used as sunscreens.
- MeSH
- antibakteriální látky * chemie farmakologie účinky záření MeSH
- azosloučeniny chemie MeSH
- barvicí látky chemie MeSH
- benzensulfonáty chemie MeSH
- buňky 3T3 MeSH
- Escherichia coli účinky léků MeSH
- farmaceutická chemie MeSH
- kožní absorpce MeSH
- kůže metabolismus MeSH
- kyselina askorbová chemie MeSH
- myristáty chemie MeSH
- myši MeSH
- nanočástice * chemie účinky záření MeSH
- prasata MeSH
- přípravky chránící proti slunci * chemie farmakologie účinky záření MeSH
- Staphylococcus epidermidis účinky léků MeSH
- techniky in vitro MeSH
- titan * chemie farmakologie účinky záření MeSH
- ultrafialové záření MeSH
- velikost částic MeSH
- voda chemie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Photochemical degradation of atrazine under different conditions was studied and compared, namely degradation via photocatalysis on TiO2, UV C photolysis, and homogeneous photocatalysis in the presence of added ferric ions. The reaction rate constants in heterogeneous photocatalytic reactions on TiO2 and of photolytic degradation by means of UV C light are similar, 0.018 min(-1) and 0.020 min(-1), respectively. The reaction rate constants in homogeneous photocatalytic reactions with Fe(III) added depend strongly on the Fe(III) concentration, 0.0017 min(-1) for 1.6 × 10(-6) mol l(-1) Fe(III) to 0.105 min(-1) for 3.3 × 10(-4) mol l(-1) Fe(III). In all types of reactions, dechlorination was observed; in homogeneous photocatalytic reactions and in UV C (250-300 nm) photolysis, dechlorination proceeds with a 1 : 1 stoichiometry to atrazine degradation, in photocatalytic reactions on TiO2, dechlorination measured as chloride ion release reaches only 1/5 of the substrate degradation. In photocatalytic reactions on TiO2, mineralisation of 40% carbon was observed.
Radio frequency plasma is one of the means to modify the polymer surface namely in the activation of polypropylene membranes (PPM) with O2 plasma. Activated membranes were deposited with TiO2 nanoparticles by the dip coating method and the bare sample and modified sample (PPM5-TiO2) were irradiated by UV lamps for 20-120 min. Characterization techniques such as X-ray diffraction (XRD), Attenuated total reflection technique- Fourier transform infrared spectroscopy (ATR-FTIR), Thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM) and water contact angle (WCA) measurements were applied to study the alteration of ensuing membrane surface properties which shows the nanoparticles on the sample surface including the presence of Ti on PPM. The WCA decreased from 135° (PPM) to 90° (PPM5-TiO2) and after UV irradiation, the WCA of PPM5-TiO2 diminished from 90° to 40°.
- MeSH
- difrakce rentgenového záření MeSH
- fotoelektronová spektroskopie MeSH
- kyslík chemie MeSH
- membrány umělé * MeSH
- nanočástice chemie MeSH
- plazmové plyny chemie MeSH
- polypropyleny chemie MeSH
- smáčivost MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- teplota MeSH
- termogravimetrie MeSH
- titan chemie MeSH
- voda chemie MeSH
- Publikační typ
- časopisecké články MeSH
Titanium oxide (TiO2) and iron oxide (α-Fe2O3) hematite films have potential applications as photoanodes in electrochemical water splitting. In the present work TiO2 and α-Fe2O3 thin films were prepared by two methods, e.g., sol-gel and High Power Impulse Magnetron Sputtering (HiPIMS) and judged on the basis of physical properties such as crystalline structure and surface topography and functional properties such as simulated photoelectrochemical (PEC) water splitting conditions. It was revealed that the HiPIMS method already provides crystalline structures of anatase TiO2 and hematite Fe2O3 during the deposition, whereas to finalize the sol-gel route the as-deposited films must always be annealed to obtain the crystalline phase. Regarding the PEC activity, both TiO2 films show similar photocurrent density, but only when illuminated by UV light. A different situation was observed for hematite films where plasmatic films showed a tenfold enhancement of the stable photocurrent density over the sol-gel hematite films for both UV and visible irradiation. The superior properties of plasmatic film could be explained by ability to address some of the hematite drawbacks by deposition of very thin films (25 nm) consisting of small densely packed particles and by doping with Sn.
The ecotoxicological effect of after-usage released TiO2 nanoparticles in aquatic resources has been a major concern owing to their production and utilization in different applications. Addressing the issue, this study investigates the detailed in vivo molecular toxicity of TiO2 nanoparticles with Paramecium caudatum. TiO2 nanoparticles were synthesized at a lab scale using high energy ball milling technique; characterized for their physicochemical properties and investigated for their ecotoxicological impact on oxidative stress, steatosis, and apoptosis of cells through different biochemical analysis, flow cytometry, and fluorescent microscopy. TiO2 nanoparticles; TiO2 (N15); of size 36 ± 12 nm were synthesized with a zeta potential of - 20.2 ± 8.8 mV and bandgap of 4.6 ± 0.3 eV and exhibited a blue shift in UV-spectrum. Compared to the Bulk TiO2, the TiO2 (N15) exhibited higher cytotoxicity with a 24 h LC50 of 202.4 μg/ml with P. Caudatum. The mechanism was elucidated as the size and charge-dependent internalization of nanoparticles leading to abnormal physiological metabolism in oxidative stress, steatosis, and apoptosis because of their influential effect on the activity of metabolic proteins like SOD, GSH, MDA, and catalase. The study emphasized the controlled usage TiO2 nanoparticles in daily activity with a concern for ecological and biomedical aspects.
- MeSH
- apoptóza MeSH
- nanočástice * chemie toxicita MeSH
- oxidační stres MeSH
- Paramecium caudatum * MeSH
- titan toxicita MeSH
- Publikační typ
- časopisecké články MeSH
Sdělení představuje souhrn aktuálních znalostí o fotokatalytickém jevu na povrchu nanočástic TiO2, přehled publikovaných sdělení o jejich známých a potenciálních zdravotních účincích, o biocidním působení i o možném využití v oblastí zlepšení kvality životního prostředí. Součástí je i přehledná diskuze reklamních tvrzení producentů nátěrů obsahujících nanočástice TiO2.
Presented is a summary of current knowledge about the photocatalytic effect on the surface of TiO2 nanoparticles, review of published information and documents about the potential health effects, about their biocidal activity and about possible use of photocatalysis in improving the quality of the environment. It also includes a transparent discussion on advertising claims of producers of paints containing nanoforms TiO2.
- Klíčová slova
- oxid titančitý (TiO2),
- MeSH
- bezpečnost MeSH
- dezinficiencia normy škodlivé účinky MeSH
- environmentální zdraví MeSH
- fotochemické procesy MeSH
- inhalační expozice MeSH
- inzerce jako téma MeSH
- látky znečišťující vzduch účinky záření MeSH
- lidé MeSH
- nanočástice * škodlivé účinky MeSH
- nátěrové hmoty * normy škodlivé účinky využití MeSH
- testování materiálů MeSH
- titan * škodlivé účinky MeSH
- ultrafialové záření MeSH
- znečištění vzduchu ve vnitřním prostředí prevence a kontrola MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
BACKGROUND: The emergence of antibiotic resistance in pathogenic bacteria has become a global threat, encouraging the adoption of efficient and effective alternatives to conventional antibiotics and promoting their use as replacements. Titanium dioxide nanoparticles (TiO2 NPs) have been reported to exhibit antibacterial properties. In this study, we synthesized and characterized TiO2 NPs in anatase and rutile forms with surface modification by geraniol (GER). RESULTS: The crystallinity and morphology of modified TiO2 NPs were analyzed by UV/Vis spectrophotometry, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM) with elemental mapping (EDS). The antimicrobial activity of TiO2 NPs with geraniol was assessed against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli. The minimum inhibitory concentration (MIC) values of modified NPs ranged from 0.25 to 1.0 mg/ml against all bacterial strains, and the live dead assay and fractional inhibitory concentration (FIC) supported the antibacterial properties of TiO2 NPs with GER. Moreover, TiO2 NPs with GER also showed a significant decrease in the biofilm thickness of MRSA. CONCLUSIONS: Our results suggest that TiO2 NPs with GER offer a promising alternative to antibiotics, particularly for controlling antibiotic-resistant strains. The surface modification of TiO2 NPs by geraniol resulted in enhanced antibacterial properties against multiple bacterial strains, including antibiotic-resistant MRSA. The potential applications of modified TiO2 NPs in the biomedical and environmental fields warrant further investigation.
Malaria is a serious global health challenge, and it has infected millions of people worldwide. There is an urgent need for new antimalarial drugs and drug targets for both prophylaxis and chemotherapy. In the present study, we biosynthesized TiO2 nanoparticles (NPs) using the Momordica charantia leaf aqueous extract as a reducing and stabilizing agent. TiO2 NPs were characterized by UV, XRD, FTIR, HRTEM, EDX, DLS and Zeta-potential. The maximum activity of mosquitocidal was observed in the synthesized TiO2 NPs against Anopheles stephensi Liston (Diptera: Culicidae) larvae and pupae, LC50 were 2.50 mg/l (I instar), 2.86 mg/l (II), 3.29 mg/l (III), 3.43 mg/l (IV), and 5.04 mg/l (pupa). The antimalarial activity of M. charantia leaf aqueous extract and TiO2 NPs were evaluated against CQ-resistant (CQ-r) and CQ sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of M. charantia leaf aqueous extract were 83.64 μg/ml (CQ-s) and 88.14 μg/ml (CQ-r). Synthesized TiO2 NPs achieved IC50 of 53.42 μg/ml (CQ-s) and 59.71 μg/ml (CQ-r). The TiO2 NPs did not exhibit any noticeable toxicity on Poecilia reticulata after 24 h of exposure. Overall, our results suggest that the synthesized TiO2 NPs may be employed to develop newer and safer agents for malaria control.
The aim of present study was to assess the toxicological effects of transition metal-doped titanium dioxide nanoparticles (TiO2 NPs) on histopathological changes, behavioral patterns, and antioxidant responses of goldfish (Carassius auratus) and common carp (Cyprinus carpio). The synthesized nanoparticles were confirmed by Transmission Electron Microscopy, Field Emission Scanning Electron Microscopy, X-ray diffraction, UV-visible, and Vibration Sample Magnetometer. Fish in four experimental groups exposed to sub-lethal concentrations of pure TiO2 NPs (10 mg L-1), chromium (Cr), iron (Fe), and nickel (Ni) doped TiO2 NPs for seven days. Statistical analysis of oxidative stress responses in gills showed significant differences in superoxide dismutase, total antioxidant capacity, and malondialdehyde parameters between two species and in all parameters than glutathione peroxidase between experimental groups and control group. In intestine, no significant difference was observed among groups, but oxidative responses were markedly different in all parameters among fish species. The histopathological analysis showed hyperplasia, fusion, and aneurism in the gills as well as degeneration, integration of villi, necrosis and erosion of the intestine. Our findings indicated that compare to pure TiO2 NPs, exposure to transition metals-doped TiO2 NPs induced oxidative stress and histopathological changes in both fish species.
