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1.
Mikrochim Acta ; 186(12): 844, 2019 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-31768658

RESUMO

A "detect and destroy" strategy is reported for the spectroscopic determination and photocatalytic degradation of Malachite Green (MG) in aqueous solutions. The intensity of the reflection peak maxima from the TiO2-coated 2D-photonic crystal (PhC) at 633 nm wavelength undergoes a gradual decrease with increasing concentrations of MG. The determination of MG was readily achieved in the nanomolar range due to the quenching of the reflection intensity of the peak, measured using a fiber optic probe. The assay works in the 1.0 nM to 10 µM MG concentration range with a detection limit of 1.3 nM. The same TiO2-coated 2D-PhC surface can photocatalytically degrade MG in aqueous solutions under UV irradiation. The photocatalytic degradation in the presence of TiO2-coated 2D-PhC becomes evident as the blue color of MG changes to colorless with increasing irradiation time. The decrease in absorption is detected at 617 nm. It was found that the photocatalytic efficiency of TiO2 was synergistically enhanced in the presence of 2D-PhCs. It is concluded that each component of the TiO2-coated 2D-PhC system plays a key role in the detection and degradation of MG. Graphical abstractSchematic representation for reflectometric detection and photocatalytic degradation of hazardous Malachite Green dye using TiO2-coated two-dimensional photonic crystals.


Assuntos
Corantes de Rosanilina/análise , Corantes de Rosanilina/efeitos da radiação , Espectrofotometria Ultravioleta/métodos , Titânio/química , Catálise/efeitos da radiação , Desinfetantes/análise , Desinfetantes/efeitos da radiação , Água Potável/análise , Água Doce/análise , Limite de Detecção , Estudo de Prova de Conceito , Titânio/efeitos da radiação , Raios Ultravioleta , Águas Residuárias/análise , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/efeitos da radiação
2.
Analyst ; 144(19): 5717-5723, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31482883

RESUMO

An innovative visible light-driven photoelectrochemical (PEC) immunosensing system was reasonably established for the sensitive detection of prostate-specific antigen (PSA) by using perovskite metal oxide@gold nanoparticle heterostructures (BaTiO3/Au) as the photoactive materials. When plasmonic Au nanoparticles were directly decorated on BaTiO3, a several times surface plasmon resonance (SPR) enhancement of photocurrent density was induced via the injection of hot electrons from visible light-excited Au nanoparticles into the conduction band of BaTiO3, and the combination of BaTiO3 and Au nanoparticles was employed as a promising platform for developing a photoelectrochemical bioanalysis. As a proof of concept, PSA had been detected by the BaTiO3/Au nanocomposite-based PEC sensor. To design such an immunoassay protocol, a monoclonal anti-PSA capture antibody (cAb)-coated microplate and glucose oxidase/polyclonal anti-PSA detection antibody-modified gold nanoparticles (GOx-Au NP-dAb) were used as the immunoreaction platform and signal probe, respectively. Upon the addition of target PSA, a sandwiched immunocomplex was formed accompanying the immuno-recognition between the antigen and antibody, and then the carried GOx could oxidize glucose to produce H2O2. The photocurrent of the BaTiO3/Au nanocomposite-functionalized electrode amplified with increasing H2O2 concentration since H2O2 is considered as a good hole scavenger. On the basis of the above-mentioned mechanisms and the optimized conditions, the assembled PEC immunosensor was linear with the logarithm of the PSA concentration in the range of 0.01-40 ng mL-1 with a detection limit of 4.2 pg mL-1. It afforded rapid response, good precision, and high stability and specificity, implying its great promise in photoelectrochemical immunoassays. More generally, this system sets up an ideal PEC immunosensing system based on the BaTiO3/Au nanocomposites and represents an innovative and low-cost "signal-on" assay scheme for the practical quantitative screening of low-abundance proteins.


Assuntos
Compostos de Bário/química , Ouro/química , Calicreínas/sangue , Nanopartículas Metálicas/química , Antígeno Prostático Específico/sangue , Titânio/química , Anticorpos Monoclonais/imunologia , Compostos de Bário/efeitos da radiação , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Glucose/análise , Glucose Oxidase/química , Ouro/efeitos da radiação , Humanos , Peróxido de Hidrogênio/química , Imunoensaio/métodos , Calicreínas/imunologia , Luz , Limite de Detecção , Nanopartículas Metálicas/efeitos da radiação , Nanocompostos/química , Nanocompostos/efeitos da radiação , Processos Fotoquímicos , Estudo de Prova de Conceito , Antígeno Prostático Específico/imunologia , Ressonância de Plasmônio de Superfície/métodos , Titânio/efeitos da radiação
3.
Molecules ; 24(17)2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31438511

RESUMO

The antibacterial activity of concrete plates loaded with various titania photocatalysts was investigated. The target in bacteria testing was Escherichia coli K12. The presence of photocatalysts in the concrete matrix at a dose of 10 wt.% improved the antibacterial properties, which became significant depending on the type of the added photocatalyst. Total inactivation of E. coli irradiated under artificial solar light was observed on the concrete plates loaded with the following photocatalysts: TiO2/N,CMeOH-300, TiO2/N,CEtOH-100, TiO2/N,CisoPrOH-100 and TiO2/N-300. The modified Hom disinfection kinetic model was found as a best-fit model for the obtained results. The presence of nitrogen and carbon in the photocatalysts structure, as well as crystallite size, surface area and porosity, contributed to the increase of antibacterial properties of concrete plates.


Assuntos
Luz , Fotoquímica/métodos , Titânio/química , Catálise , Escherichia coli/efeitos da radiação , Cinética , Titânio/efeitos da radiação
4.
Mikrochim Acta ; 186(8): 490, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31267219

RESUMO

A photoelectrochemical (PEC) method has been developed for sensitive detection of trypsin. It is based on the use of a composite consisting of MoS2 nanosheets and TiO2 nanorods (MoS2-TiO2). The material has a high specific surface area, superior electrical conductivity, excellent biocompatibility and good band gap matching. The composite was synthesized by a one-pot method using TiO2 as a template. This results in a uniform distribution of the MoS2 nanosheets (<5 layers) in the composite. If the composite, placed on an indium tin oxide (ITO) electrode, is coupled to apoferritin, the photocurrent response decreases due to the insulating effect of the protein. Trypsin, in acting as an alkaline protease, decomposes the apoferritin. This results in the recovery of the PEC signal. Attractive features of this PEC method include (a) a superior PEC signal, (b) sensor stability, (c) simple operation, and (d) the lack of any additional modifications of the biosensor. This warrants high sensitivity, reproducibility, repeatability and practicality. The ITO sensor has a linear response in the 1 to 1000 ng·mL-1 trypsin concentration range and a 0.82 ng·mL-1 detection limit. The assay was applied to the determination of trypsin in spiked serum samples and gave satisfactory results. Graphical abstract Schematic presentation of an indium tin oxide (ITO)/MoS2-TiO2 sensor for detecting trypsin. The PEC signal was decreased after immobilization of apoferritin (APO) on the modified ITO. Trypsin catalytically hydrolyzes APO specifically and induces the PEC signal to recover.


Assuntos
Técnicas Biossensoriais , Tripsina/análise , Catálise , Dissulfetos/química , Dissulfetos/efeitos da radiação , Técnicas Eletroquímicas , Eletrodos , Humanos , Luz , Molibdênio/química , Molibdênio/efeitos da radiação , Nanoestruturas/química , Nanoestruturas/efeitos da radiação , Processos Fotoquímicos , Compostos de Estanho/química , Titânio/química , Titânio/efeitos da radiação , Tripsina/sangue , Tripsina/química
5.
BMC Musculoskelet Disord ; 20(1): 292, 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-31208382

RESUMO

BACKGROUND: Titanium instrumentations are widely used in orthopedics; the metal bonds with bone in a process called osseointegration. Over time, hydrocarbons adhere to the instrumentation, which weakens the bone-binding ability. Ultraviolet photofunctionalization enhances the bone-binding ability of instrumentation by reducing hydrocarbons. The process has been proven effective in dentistry, but its effects in orthopedics are unverified. We aimed to determine the effect of ultraviolet photofunctionalization of titanium instrumentation used in lumbar fusion. METHODS: This was a non-randomized controlled trial. We prospectively enrolled 13 patients who underwent lumbar fusion surgery. We inserted two pure titanium cages into each intervertebral space; one cage had undergone ultraviolet photofunctionalization, while the other was untreated. The degree of osteosclerosis around both cages was then compared by measuring the densities around the cages on imaging at 2, 3, 6, and 12 months postoperatively compared with 1 month postoperatively. The carbon attachment of the titanium cages was measured using X-ray photoelectron spectroscopy. RESULTS: There was no significant difference between the degree of osteosclerosis (as assessed by the density) around the treated versus untreated cages at any timepoint. The ratio of carbon attachment of the titanium cages was only 20%, which was markedly less than the ratio of carbon attachment to titanium instrumentation previously reported in the dentistry field. CONCLUSIONS: The effect of ultraviolet photofunctionalization of titanium instrumentation in spine surgery is questionable at present. The biological aging of the titanium may be affected by differences in the manufacturing process of orthopedics instrumentation versus dentistry instrumentation. TRIAL REGISTRATION: UMIN Clinical Trials Registry (Identifier: UMIN000014103 ; retrospectively registered on June 1, 2014).


Assuntos
Interface Osso-Implante/efeitos da radiação , Osseointegração/efeitos da radiação , Fusão Vertebral/instrumentação , Titânio/efeitos da radiação , Raios Ultravioleta , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Masculino , Pessoa de Meia-Idade , Osteosclerose/diagnóstico por imagem , Osteosclerose/prevenção & controle , Estudos Prospectivos , Estudos Retrospectivos , Fusão Vertebral/efeitos adversos , Fusão Vertebral/métodos , Titânio/efeitos adversos , Tomografia Computadorizada por Raios X , Resultado do Tratamento
6.
Chemosphere ; 234: 204-214, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31220654

RESUMO

In drinking water treatment, complete mineralization of organophosphorus pesticides (OPPs) by UV-based advanced oxidation processes (UV AOPs) is rarely achieved. The formation of intermediate oxidation byproducts would likely have some profound effects on toxicity of the reaction solutions. This study investigated the intermediate oxidation byproducts, transformation pathway and toxicity of malathion solutions during the treatment processes of UV alone, UV/H2O2, UV/TiO2 and UV/Fenton. The main intermediate oxidation byproducts were derived using ultra-performance liquid chromatography - electrospray - time-of-flight mass spectrometry. Thereby the transformation pathway for each of these treatment processes was proposed. The results indicate that in UV photolysis, the transformation pathway of malathion proceeded initially via cleavage of the phosphorus-sulfur bonds while in photocatalysis, the desulfurization from a PS bond to a PO bond was the primary degradation pathway. Interestingly, only in the UV/TiO2 process a small fraction of malathion was found decomposed via a demethylation reaction. At the same time, a toxicity assessment of the treated solutions was conducted by both luminescence inhibition of Vibrio fischeri and inhibition of acetylcholinesterase (AChE). It was found that after UV AOP treatment, the toxicity of the malathion aqueous solution increased sharply. In contrast, no increase in toxicity was observed for the malathion aqueous solution after UV alone treatment. This study demonstrates that the high removal efficiency achieved by OPPs does not imply that detoxification of the water solution has been achieved. On the contrary, the toxicity of the treated solutions by OPPs may be increased significantly depending on the selected treatment processes.


Assuntos
Aliivibrio fischeri/crescimento & desenvolvimento , Inseticidas/toxicidade , Malation/toxicidade , Fotólise , Raios Ultravioleta , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos , Aliivibrio fischeri/efeitos dos fármacos , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/efeitos da radiação , Ferro/química , Ferro/efeitos da radiação , Oxirredução , Titânio/química , Titânio/efeitos da radiação , Poluentes Químicos da Água/química
7.
Molecules ; 24(11)2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31174409

RESUMO

The photocatalytic activities of reduced titanium dioxide (TiO2) materials have been investigated by measuring their ability to produce hydroxyl radicals under UV and visible light irradiation. Degussa P25 TiO2 was doped with nitrogen (N), fluorine (F), and/or phosphorus (P) and then subjected to surface modification employing a thermo-physicochemical process in the presence of reducing agent sodium borohydride (NaBH4). The reduced TiO2 materials were characterized by a number of X-ray, spectroscopic and imaging methods. Surface doping of TiO2 was employed to modulate the band gap energies into the visible wavelength region for better overlap with the solar spectrum. Hydroxyl radical generation, central to TiO2 photocatalytic water purification applications, was quantitated using coumarin as a trap under UV and visible light irradiation of the reduced TiO2 materials. At 350 nm irradiation, the yield of hydroxyl radicals generated by the reduced forms of TiO2 was nearly 90% of hydroxyl radicals generated by the Degussa P25 TiO2. Hydroxyl radical generation by these reduced forms of TiO2 was also observed under visible light irradiation (419 and 450 nm). These results demonstrated that simple surface modification of doped TiO2 can lead to visible light activity, which is important for more economical solar-driven applications of TiO2 photocatalysis.


Assuntos
Radical Hidroxila/química , Processos Fotoquímicos , Titânio/química , Flúor/química , Radical Hidroxila/efeitos da radiação , Luz , Nitrogênio/química , Fósforo/química , Titânio/efeitos da radiação , Raios Ultravioleta
8.
Carbohydr Polym ; 216: 189-196, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31047056

RESUMO

In this study, the composite of carboxymethyl cellulose (CMC) film modified with gelatin and TiO2-Ag nanoparticles (CMC/Gel/TiO2-Ag) was prepared and some properties of synthesized film including physicochemical and photocatalytic properties were investigated. FT-IR results showed that new interactions between the film components were created. Scanning electron microscopy (SEM) results showed that the TiO2-Ag particles with 50-100 nm distributed in the CMC/Gelatin film. The results of the mechanical test showed that the TiO2-Ag nanoparticles at low concentrations increased tensile strength (TS) and decreased strain to break (STB), but with increasing nanoparticles concentrations, TS decreased and STB increased. Photocatalytic study showed that the prepared CMC/Gel/TiO2-Ag film has good photocatalytic property. Gas chromatography was used to study photocatalytic effects of film. Increasing TiO2-Ag nano particles on the film increases the photocatalytic activity of films against NH3, ethanol and benzene.


Assuntos
Plásticos Biodegradáveis/química , Carboximetilcelulose Sódica/química , Gelatina/química , Nanopartículas Metálicas/química , Prata/química , Titânio/química , Amônia/química , Benzeno/química , Plásticos Biodegradáveis/síntese química , Plásticos Biodegradáveis/efeitos da radiação , Carboximetilcelulose Sódica/síntese química , Carboximetilcelulose Sódica/efeitos da radiação , Catálise , Módulo de Elasticidade , Etanol/química , Gelatina/síntese química , Gelatina/efeitos da radiação , Luz , Membranas Artificiais , Nanopartículas Metálicas/efeitos da radiação , Nanocompostos/química , Nanocompostos/efeitos da radiação , Permeabilidade , Prata/efeitos da radiação , Vapor , Resistência à Tração , Titânio/efeitos da radiação , Água/química
9.
ACS Sens ; 4(6): 1670-1681, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31117365

RESUMO

Semiconductor materials have become competitive candidates for surface-enhanced Raman scattering (SERS) substrates; however, their limited SERS sensitivity hinders the practical applications of semiconductors. Here, we develop a hybrid substrate by integrating anatase/rutile TiO2 heterostructure with dense plasmonic hotspots of Ag nanoparticle (AgNPs) for efficient photoinduced enhanced Raman spectroscopy (PIERS). The PIERS mechanism is systematically investigated by means of a portable Raman instrument. When ultraviolet (UV) light irradiates the substrate, the TiO2-Ag hybrid arrays produce remarkable charge-transfer enhancement, which can be ascribed to the highly efficient charge separation driven by heterojunction and transfer from TiO2 heterostructure to AgNPs. This platform allows for the rapid detection of multifold organic species, including malachite green (MG), crystal violet (CV), rhodamine 6G (R6G), thiram, and acephate, and as high as 27.8-fold enhancement over the normal SERS is achieved, representing the highest PIERS magnification up to the present time. The intensive PIERS enhancement makes it ultrasensitively detect analyte concentration of an order of magnitude lower than that of SERS method. The improved sensitivity and resolution can be readily realized by simple UV irradiation, which represents a major advantage of our PIERS methodology. Besides, the integration of uniform TiO2 heterostructure arrays with AgNPs generates superior signal reproducibility with relative standard deviation (RSD) value of less than 14%. In addition, the detected molecules on the substrate can be eliminated by photocatalytic degradation after PIERS measurements by using UV irradiation, which makes the substrate reusable for 15 cycles. The ultrahigh sensitivity, superior reproducibility, and excellent recyclability displayed by our platform may provide new opportunities in field detection analysis coupled with a portable Raman instrument.


Assuntos
Poluentes Ambientais/análise , Nanopartículas Metálicas/química , Semicondutores , Violeta Genciana/análise , Limite de Detecção , Nanopartículas Metálicas/efeitos da radiação , Nanotubos/química , Nanotubos/efeitos da radiação , Compostos Organotiofosforados/análise , Fosforamidas , Reprodutibilidade dos Testes , Rodaminas/análise , Corantes de Rosanilina/análise , Prata/química , Prata/efeitos da radiação , Análise Espectral Raman/métodos , Tiram/análise , Titânio/química , Titânio/efeitos da radiação , Raios Ultravioleta
10.
Environ Monit Assess ; 191(4): 206, 2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30838462

RESUMO

Titania nanoparticles with two crystalline structures (anatase-rutile) and coated titania with different amount of tin dioxide (A-R-S#1 and A-R-S#2) are prepared through hydrolysis method. X-ray diffraction analysis (XRD) confirmed the presence of both anatase and rutile structures in the synthesized titania nanoparticles. In addition, the characteristic peak of tin dioxide in A-R-S#2 was higher than that of A-R-S#1. The photocatalytic activity of the prepared photocatalysts was evaluated using a vapor mercury lamp (150 W) for decomposition of methylene blue. The results of the photocatalytic activity variation showed that the photocatalytic activity of all the synthesized photocatalysts increases by increasing the UV irradiation time (in the range of 5 min to 20 min) and weight fraction of photocatalysts (pH = 4, pH = 8, pH = 12). The pH of suspension had negative effect on photocatalytic activity. The least and most photocatalytic activity belonged to the synthesized anatase-rutile titania and A-R-S#2, respectively. Increasing the amount of tin dioxide nanoparticles on the surface of titania leads to the enhancement of photocatalytic activity. The results of the analysis of variance showed that all the main factors and their binary and triple interactions significantly affect photocatalytic activity.


Assuntos
Azul de Metileno/química , Nanopartículas , Compostos de Estanho , Titânio , Poluentes Químicos da Água/química , Catálise , Nanopartículas/química , Nanopartículas/efeitos da radiação , Fotólise , Compostos de Estanho/química , Compostos de Estanho/efeitos da radiação , Titânio/química , Titânio/efeitos da radiação , Raios Ultravioleta
11.
J Environ Sci (China) ; 79: 153-160, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30784440

RESUMO

Various methods for shifting the optical response of TiO2 into the visible (Vis) range have been reported. Herein, we reported the application of a TiO2/H2O2/Vis process and the effects of TiO2 crystalline structure on the degradation of terbuthylazine. The results indicated that TiO2 crystalline structure and H2O2 addition had significant effects on terbuthylazine degradation: its degradation rate could be increased from 7% to 70% with H2O2 addition after 180 min of reaction, the synergistic degradation of terbuthylazine by TiO2-Fe3+ was substantially accelerated, with the degradation rate reaching up to 100% after 20 min of reaction, and rutile TiO2 showed better photocatalytic activity and a more obvious synergistic effect than anatase TiO2. The addition of free-radical scavengers (tert-butyl alcohol or methanol) inhibited the degradation efficiency of rutile TiO2, but had a relatively minor effect on anatase TiO2. Fluorescence spectrophotometry analysis indicated that hydroxyl free radicals could be continuously produced when using rutile TiO2 as the photocatalyst. Degradation of terbuthylazine catalyzed by rutile TiO2 occurred mainly in solution, but occurred on the particle surface of the photocatalyst when catalyzed by anatase TiO2. This study provides new insight into the role of TiO2 crystalline structure on the degradation of terbuthylazine and its photocatalytic degradation mechanism.


Assuntos
Peróxido de Hidrogênio/química , Titânio/química , Triazinas/química , Poluentes Químicos da Água/química , Catálise , Cristalização , Peróxido de Hidrogênio/efeitos da radiação , Luz , Fotólise , Titânio/efeitos da radiação
12.
J Environ Sci (China) ; 79: 213-224, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30784444

RESUMO

In this study, a baffled photocatalytic reactor was used for the treatment of colored wastewater containing the azo dye of Acid Orange 52 (AO52). A study on the active species of the photocatalytic process using TiO2 nanoparticles indicated that hydroxyl radical and superoxide have the greatest contribution to the dye degradation process respectively. Given that a level of biological oxygen demand/chemical oxygen demand (BOD5/COD) equal to 0.4 was achieved after about 5 hr from the beginning of the experiment, the reactor seems to be capable of purifying the wastewater containing AO52 dye after this time in order to discharge into a biological treatment system to continue the treatment process. The results of the liquid chromatography-mass spectrometry (LC-MS) test showed that during the first 4 hr of the experiment, with the breakdown of the azo bond, the contaminant was decomposed into the benzene annular compounds with less toxicity indicating a reduction in the toxicity of wastewater after removing the dye agent. The study on the kinetics of these reactions followed the pseudo-first-order kinetic model in all conditions and corresponded well to Langmuir-Hinshelwood model. According to the kinetic model for the simultaneous occurrence of possible pathways, the kinetic constant of production and degradation of intermediate products in optimal conditions was estimated to be between 0.0029 and 0.0391 min-1.


Assuntos
Compostos Azo/química , Corantes/química , Nanopartículas/efeitos da radiação , Titânio/efeitos da radiação , Poluentes Químicos da Água/química , Catálise , Cinética , Luz , Nanopartículas/química , Fotólise , Titânio/química , Eliminação de Resíduos Líquidos/métodos
13.
Talanta ; 196: 293-299, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30683366

RESUMO

A sensitive photoelectrochemical (PEC) biosensor for determination of alkaline phosphatase (ALP) activity was constructed based on a photo-excited electron transfer strategy. Immobilization of CdTe quantum dots (QDs) on TiO2 nanotube arrays (TNAs), addition of iron (III) and adenosine triphosphate (ATP) in turn can effectively adjust the photocurrent response of TNAs under visible light irradiation due to a photo-excited electron transfer process, and alkaline phosphatase (ALP) activity can be determined for its catalysis toward dephosphorylation of ATP. The preparation of CdTe QDs, construction of TNA/QD PEC biosensor and the mechanism of photo-excited electron transfer are investigated in the present work. Under the optimal experimental conditions, the TNA/QD PEC biosensor shows a low limits of detection (LODs) (0.05 U L-1) and limits of quantification detection (LOQs) (0.15 U L-1), wide linear range from 0.2 to 15 U L-1, and good selectivity towards ALP determination, which has been successfully applied for human serum analysis with good precision (RSD ≤ 5.4%) and high accuracy (recovery rate, 91-112%).


Assuntos
Fosfatase Alcalina/química , Técnicas Biossensoriais , Trifosfato de Adenosina/química , Compostos de Cádmio/química , Técnicas Eletroquímicas , Transporte de Elétrons , Ferro/química , Luz , Nanotubos/química , Nanotubos/efeitos da radiação , Pontos Quânticos/química , Telúrio/química , Titânio/química , Titânio/efeitos da radiação
14.
Dent Mater J ; 38(1): 68-74, 2019 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-30449826

RESUMO

The evaluation of the photocatalysis of visible light activated titanium dioxide employed in hydrogen peroxide (H2O2) was carried using seven H2O2 solutions (3.5 and 35%) and/or methylene blue (MB), with or without light irradiation (LI); the absorbance of MB was the bleaching indicator. Color analysis was performed on bovine teeth (n=12) using two different concentrations of H2O2, 6 and 35% associated with titanium dioxide (TiO2). Data were analyzed with one and two-way ANOVA, and significance level of p<0.05. Solutions containing MB, H2O2 at 3.5 or 35%, and TiO2, followed by LI, showed significant difference when compared with other groups. Greater MB reduction was found in 35% concentration. H2O2 35%+TiO2 gel showed no difference in comparison to control group. All groups for the color analysis assay showed ΔE higher than 3.3. In conclusion, TiO2 and H2O2 association is a promisor alternative for reducing the clinical time of in-office dental bleaching.


Assuntos
Peróxido de Hidrogênio/efeitos da radiação , Luz , Processos Fotoquímicos , Titânio/efeitos da radiação , Clareadores Dentários/efeitos da radiação , Clareamento Dental/instrumentação , Animais , Bovinos , Cor , Técnicas In Vitro , Azul de Metileno , Soluções
15.
Radiat Prot Dosimetry ; 184(2): 248-255, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30508125

RESUMO

Many dosimetric applications and especially those involved in clinical dosimetry are hampered by the supralinearity of TLD-100 which begins at a level of dose of 1 Gy. This research investigates the effect of optical excitation following irradiation on the dose-response. It is expected that this will lead to a more linear dose-response, however, irrespective of the hoped-for linearity, the theoretical/kinetic simulations of the effect of optical excitation will further enhance our understanding of the thermoluminescence mechanisms, especially the role of spatially correlated trapping and luminescent centers. In the following, the various stages carried out in these investigations are discussed and preliminary results presented.


Assuntos
Fluoretos/química , Compostos de Lítio/química , Magnésio/química , Dosimetria Termoluminescente/instrumentação , Dosimetria Termoluminescente/métodos , Titânio/química , Desenho de Equipamento , Fluoretos/efeitos da radiação , Humanos , Compostos de Lítio/efeitos da radiação , Magnésio/efeitos da radiação , Doses de Radiação , Titânio/efeitos da radiação
16.
J Photochem Photobiol B ; 190: 137-145, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30529924

RESUMO

Over the past decades, nanotechnology has received great attention and brought revolutionary solutions for a number of challenges in scientific fields. Industrial, agricultural and medical applications of engineered nanomaterials have increased intensively. The ability of titanium dioxide nanoparticles (TiO2 NPs) to produce reactive oxygen species (ROS), when excited by ultra-violet (UV) light, makes them useful for effectively inactivate various pathogens. It is known that ROS also have signalling role in living organisms, therefore, TiO2 NPs-induced ROS can influence both enzymatic and non-enzymatic defence systems, and could play a role in the resistance of plants to pathogens. Herein, we studied the photocatalytic stress responses of grapevine (Vitis vinifera L.) as model plant, when exposed to a well-known photocatalyst, Degussa P25 TiO2 NPs. The photocatalytically produced ROS such as superoxide anion, hydroxyl radical and singlet oxygen were confirmed by electron paramagnetic resonance spectroscopy. Foliar exposure of five red cultivars (Cabernet sauvignon, Cabernet franc, Merlot, Kékfrankos and Kadarka) was carried out in blooming phenophase under field condition where plants are exposed to natural sunlight with relatively high UV radiation (with a maximum of ~ 45 W m-2). After two weeks of exposure, the effects of photogenerated ROS on the total phenolic content, antioxidant capacity, flavonol profile and the main macro-, microelements of the leaves were studied in detail. We found that foliar application of TiO2 NPs boosted the total phenolic content and biosynthesis of the leaf flavonols depending on the grapevine variety. Photocatalytically active TiO2 NPs also increased K, Mg, Ca, B and Mn levels in the leaves as shown by ICP-AES measurements.


Assuntos
Folhas de Planta/efeitos dos fármacos , Titânio/farmacologia , Vitis/química , Antioxidantes/análise , Flavonóis/análise , Nanoestruturas/química , Nanoestruturas/efeitos da radiação , Fenóis/análise , Folhas de Planta/química , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Titânio/efeitos da radiação , Raios Ultravioleta
17.
Environ Sci Pollut Res Int ; 26(17): 16877-16886, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29372521

RESUMO

Air pollution due to emission of various hazardous gases such as SO2 into the atmosphere and its control is an important environmental issue. Application of photocatalysts is considered as a suitable process to control the gaseous pollutants. In this study, the efficiency of clinoptilolite as a natural zeolite (Ze) modified by TiO2 (Ze-Ti) and a polymeric surfactant polyoxypropylene (Ze-Ti-POP) for removal of SO2 was investigated. The nanocomposites were characterized by SEM, EDX, and BET analyses. The photocatalytic oxidation experiments of SO2 by the nanocomposites and natural zeolite were done under UV irradiation with initial SO2 concentration of 500 ppm in a photoreactor. The effects of different factors including reaction time, catalyst dose, UV irradiation intensity, humidity content, and calcination temperature and dose of TiO2 were studied. The modification of clinoptilolite by TiO2 and POP increased considerably the BET specific surface area of the nanocomposites. The results showed that maximum removal efficiencies of SO2 by Ze-Ti and Ze-Ti-POP under the optimum experimental conditions were 82.1 and 87.4%, respectively. Adsorption kinetics data well fitted with the Langmuir-Hinshelwood model. Moreover, reusing of nanocomposites after three regeneration cycles indicated that application of Ze-Ti and Ze-Ti-POP nanocomposites could be a promising approach for SO2 removal. Graphical abstract ᅟ.


Assuntos
Poluentes Atmosféricos/química , Polímeros/química , Propilenoglicóis/química , Dióxido de Enxofre/química , Tensoativos/química , Titânio/química , Poluentes Atmosféricos/análise , Catálise , Gases , Umidade , Nanocompostos/efeitos da radiação , Oxirredução , Processos Fotoquímicos , Dióxido de Enxofre/análise , Temperatura , Titânio/efeitos da radiação , Raios Ultravioleta , Zeolitas
18.
Talanta ; 192: 360-367, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30348403

RESUMO

A novel composite monolithic column based on graphene oxide-trimethyl-2-methacroyloxyethylammonium chloride-titania (GO-META-TiO2) was developed for the enrichment of phosphopeptides. META was proposed as a "bridge" to connect GO and TiO2 species to prepare GO-META-TiO2 composite. This high surface area composite (surface area = 196.93 m2 g-1) was fixed in the monolithic column via an in situ UV polymerization process. In-tube solid phase microextraction (IT-SPME) using this composite was coupled with matrix-assisted laser desorption ionization time-of-flight-mass spectrometry (MALDI-TOF-MS) for the enrichment and detection of phosphorylated peptides from a digestion mixture of α-casein, ß-casein, and bovine serum albumin (BSA) in molar ratios of 1:1:1, 1:1:10, and 1:1:100. The key factors affecting the IT-SPME of the phosphopeptides, such as the elution solution concentrations, the extraction flow rate, and the elution flow rate were comprehensively investigated. For further demonstration, this method was employed for the enrichment and detection of phosphorylated peptides from digested chicken egg white. The obtained results indicated that the GO-META-TiO2 composite monolithic column rapidly and efficiently captured the phosphopeptides present in these complex biological samples, even in the 10 fmol ß-casein tryptic digest. We therefore propose that the reported GO-META-TiO2 composite monolithic column possesses a suitable affinity for the selective extraction of phosphopeptides from biological samples. This method paves a way in extending the application of nanomaterials.


Assuntos
Nanocompostos/química , Fosfopeptídeos/análise , Microextração em Fase Sólida/instrumentação , Animais , Sequência de Bases , Caseínas/química , Bovinos , Galinhas , Colina/análogos & derivados , Colina/síntese química , Colina/química , Colina/efeitos da radiação , Clara de Ovo/química , Grafite/síntese química , Grafite/química , Grafite/efeitos da radiação , Metacrilatos/síntese química , Metacrilatos/química , Metacrilatos/efeitos da radiação , Nanocompostos/efeitos da radiação , Polimerização/efeitos da radiação , Soroalbumina Bovina/química , Microextração em Fase Sólida/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Titânio/química , Titânio/efeitos da radiação , Tripsina/química , Raios Ultravioleta
19.
Nanoscale Horiz ; 4(2): 415-425, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-32254094

RESUMO

Light-activated photoacoustic imaging (PAI) and photothermal therapy (PTT) using the second near-infrared biowindow (NIR-II, 1000-1350 nm) hold great promise for efficient tumor detection and diagnostic imaging-guided photonic nanomedicine. In this work, we report on the construction of titanium nitride (TiN) nanoparticles, with a high photothermal-conversion efficiency and desirable biocompatibility, as an alternative theranostic agent for NIR-II laser-excited photoacoustic (PA) imaging-guided photothermal tumor hyperthermia. Working within the NIR-II biowindow provides a larger maximum permissible exposure (MPE) and desirable penetration depth of the light, which then allows detection of the tumor to the full extent using PA imaging and complete tumor ablation using photothermal ablation, especially in deeper regions. After further surface polyvinyl-pyrrolidone (PVP) modification, the TiN-PVP photothermal nanoagents exhibited a high photothermal conversion efficiency of 22.8% in the NIR-II biowindow, and we further verified their high penetration depth using the NIR-II biowindow and their corresponding therapeutic effect on the viability of tumor cells in vitro. Furthermore, these TiN-PVP nanoparticles were developed as a contrast agent for NIR-II-activated PA imaging both in vitro and in vivo for the first time and realized efficient photothermal ablation of the tumor in vivo within both the NIR-I and NIR-II biowindows. This work not only provides a paradigm for TiN-PVP photothermal nanoagents working in the NIR-II biowindow both in vitro and in vivo, but also proves the feasibility of PAI and PTT cancer theranostics using NIR-II laser excitation.


Assuntos
Neoplasias da Mama/terapia , Hipertermia Induzida/métodos , Nanomedicina/métodos , Nanopartículas/uso terapêutico , Nanomedicina Teranóstica/métodos , Titânio/uso terapêutico , Técnicas de Ablação/métodos , Animais , Linhagem Celular Tumoral , Meios de Contraste/efeitos da radiação , Meios de Contraste/uso terapêutico , Meios de Contraste/toxicidade , Feminino , Raios Infravermelhos , Camundongos Endogâmicos BALB C , Nanopartículas/efeitos da radiação , Nanopartículas/toxicidade , Técnicas Fotoacústicas/métodos , Fototerapia/métodos , Titânio/efeitos da radiação , Titânio/toxicidade
20.
J Oral Sci ; 60(4): 567-573, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30587689

RESUMO

Titanium mesh plate (Ti mesh) used for bone augmentation inadvertently comes into contact with medical gloves during trimming and bending. We tested the hypotheses that glove contact degrades the biological capability of Ti mesh and that ultraviolet treatment (UV) can restore this capability. Three groups of Ti mesh specimens were prepared: as-received (AR), after glove contact (GC), and after glove contact followed by UV treatment. The AR and GC meshes were hydrophobic, but GC mesh was more hydrophobic. AR and GC meshes had significant amounts of surface carbon, and Si content was higher for GC mesh than for AR mesh. UV mesh was hydrophilic, and carbon and silicon content values were significantly lower in this group than in the AR and GC groups. The number, alkaline phosphatase activity, and mineralization ability of attached osteoblasts were significantly lower in the GC group than in the AR group and markedly higher in the UV group than in the AR group. In conclusion, glove contact caused chemical contamination of Ti mesh, which significantly reduced its bioactivity. UV treatment restored bioactivity in contaminated Ti mesh, which outperformed even the baseline Ti mesh.


Assuntos
Luvas Cirúrgicas , Osteoblastos/citologia , Titânio/química , Titânio/efeitos da radiação , Raios Ultravioleta , Fosfatase Alcalina/metabolismo , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/efeitos da radiação , Adesão Celular , Proliferação de Células , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Interações Hidrofóbicas e Hidrofílicas , Teste de Materiais , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Ratos , Ratos Sprague-Dawley , Propriedades de Superfície , Telas Cirúrgicas
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