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1.
Braz Oral Res ; 33: e079, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31531565

RESUMO

Cell therapy associated with guided bone regeneration (GBR) can be used to treat bone defects under challenging conditions such as osteoporosis. This study aimed to evaluate the effect of mesenchymal stem cells (MSCs) in combination with a poly(vinylidene-trifluoroethylene)/barium titanate (PVDF-TrFE/BT) membrane on bone repair in osteoporotic rats. Osteoporosis was induced in female rats by bilateral removal of the ovaries (OVX) or sham surgery (SHAM), and the osteoporotic condition was characterized after 5 months by microtomographic and morphometric analyses. Calvarial defects were created in osteoporotic rats that immediately received the PVDF-TrFE/BT membrane. After 2 weeks, bone marrow-derived MSCs from healthy rats, characterized by the expression of surface markers using flow cytometry, or phosphate-buffered saline (PBS) (Control) were injected into the defects and bone formation was evaluated 4 weeks post-injection by microtomographic, morphometric, and histological analyses. A reduction in the amount of bone tissue in the femurs of OVX compared with SHAM rats confirmed the osteoporotic condition of the experimental model. More bone formation was observed when the defects were injected with MSCs compared to that with PBS. The modification that we are proposing in this study for the classical GBR approach where cells are locally injected after a membrane implantation may be a promising therapeutic strategy to increase bone formation under osteoporotic condition.


Assuntos
Compostos de Bário/farmacologia , Regeneração Tecidual Guiada/métodos , Células-Tronco Mesenquimais/fisiologia , Osteogênese/efeitos dos fármacos , Osteoporose/terapia , Polivinil/farmacologia , Titânio/farmacologia , Animais , Compostos de Bário/química , Densidade Óssea , Regeneração Óssea/efeitos dos fármacos , Regeneração Óssea/fisiologia , Feminino , Citometria de Fluxo , Imagem Tridimensional , Células-Tronco Mesenquimais/química , Osteogênese/fisiologia , Osteoporose/fisiopatologia , Ovariectomia , Polivinil/química , Distribuição Aleatória , Ratos Wistar , Reprodutibilidade dos Testes , Fatores de Tempo , Titânio/química , Resultado do Tratamento
2.
Top Curr Chem (Cham) ; 377(5): 22, 2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31444578

RESUMO

A methodology for photocatalytic reactor modeling applied to advanced oxidation processes for chemical pollution abatement is presented herein. Three distinct reactor configurations typically employed in the field of air and water purification-wall reactors, slurry reactors, and fixed-bed reactors-are considered to illustrate the suggested approach. Initially, different mechanistically derived kinetic expressions to represent the photocatalytic rate of pollutant degradation are reviewed, indicating the main assumptions made by the authors in the published contributions. These kinetic expressions are needed to solve the mass balances of the reactant species in the photocatalytic reactors. As is well known, at least one of the steps of the reaction mechanism requires evaluation of the rate of electron-hole generation, which depends on the photon absorption rate: a volumetric property for reactions with the catalyst particles in aqueous suspension or a surface property for systems with a fixed catalyst deposited on an inert support. Subsequently, the different techniques for evaluating the optical properties of slurry and immobilized systems, and the numerical methods applied to calculate the photon absorption rate, are described. The experimental and theoretical results of pollutant degradation in each reactor type are then presented and analyzed. Finally, the definition, calculation, and relevance of different efficiency parameters are briefly reviewed. Using these illustrative examples, we emphasize the need for a systematic and rigorous approach for photocatalytic reactor modeling in order to overcome the inherent drawbacks of photocatalysis and to improve the overall efficiency of the process.


Assuntos
Luz , Modelos Teóricos , Poluentes Químicos da Água/química , Catálise , Ácido Clofíbrico/química , Cinética , Oxirredução , Fótons , Titânio/química
3.
Chem Commun (Camb) ; 55(71): 10571-10574, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31417999

RESUMO

A portable dual-mode sensing platform based on a self-standing TiO2 nanotube membrane is developed for simultaneously performing both qualitative analysis by the naked eye and quantitative analysis by ionic current. This dual-mode diagnosis strategy exhibits a high performance in telomerase detection in urine specimens from patients with bladder cancer.


Assuntos
Nanotubos/química , Telomerase/urina , Titânio/química , Neoplasias da Bexiga Urinária/diagnóstico , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Cor , Ouro/química , Humanos , Membranas Artificiais , Nanopartículas Metálicas/química , Prata/química , Neoplasias da Bexiga Urinária/urina
4.
J Cosmet Sci ; 70(3): 149-159, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31398103

RESUMO

Ilmenite mineral sand was used to synthesize titanium bismonohydrogen orthophosphate monohydrate, Ti(HPO4)2·H2O, and titanium phosphate, TiP2O7, two white pigments suitable in cosmetic applications. Ti(HPO4)2·H2O was obtained after digesting ilmenite in 85% phosphoric acid at 150 °C for 5 hours. On standing, unreacted ilmenite and white Ti(HPO4)2·H2O solid separated into two layers and Ti(HPO4)2·H2O was calcined at 900 °C to obtain the crystalline TiP2O7. Chemical and morphological characteristics were investigated using X-ray diffraction, transmission electron microscopy, scanning electron microscopy coupled with energy dispersive X-ray analysis, Fourier-transform infrared, and X-ray photoelectron spectroscopic techniques. The water retention (WR) capacities were measured at a relative humidity of 57% and indicate that Ti(HPO4)2·H2O and TiP2O7 have increased WR ability when compared with the pigment grade (PG) TiO2. The optical properties of Ti(HPO4)2·H2O, TiP2O7, and PG-TiO2 were compared using Ultraviolet-visible diffuse reflectance spectroscopy. The relative photoactivity of Ti(HPO4)2·H2O and TiP2O7 was determined using a chemical method based on the photobleaching behavior of a stable radical, 1,1-diphenyl 2-picrylhydrazyl. The photoactivities of Ti(HPO4)2·H2O and TiP2O7 are lower than that of PG-TiO2.


Assuntos
Titânio/química , Ferro , Microscopia Eletrônica de Varredura , Minerais
5.
Chem Commun (Camb) ; 55(65): 9697-9700, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31347623

RESUMO

An ultra-high sensitivity sensor with the function of chiral signal amplification has been proposed for the enantiomer discrimination of various amino acid enantiomers based on charge transfer (CT)-induced SERS spectroscopy. The introduced TiO2 in this sensor improves the CT behavior and discrimination efficiency distinctly and enantiomeric discrimination is realized even at low concentration.


Assuntos
Compostos de Anilina/química , Nanopartículas Metálicas/química , Compostos de Sulfidrila/química , Triptofano/análise , beta-Ciclodextrinas/química , Ligações de Hidrogênio , Fenilalanina/análise , Fenilalanina/química , Prata/química , Análise Espectral Raman/métodos , Estereoisomerismo , Titânio/química , Triptofano/química , Tirosina/análise , Tirosina/química
7.
Photochem Photobiol Sci ; 18(8): 2023-2030, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31290525

RESUMO

Rising demands for renewable energy sources have led to the development of dye sensitized solar cells. It is a challenge to find a good and low cost sensitizer, which has a low environmental impact. In this work, we conducted spectroscopic and electrochemical experiments, as well as quantum-chemical calculations of the natural pigment hypericin, in order to provide insight into its sensitizing efficiency. To this end, three identical cells were made and characterized. Although this pigment exhibited good adsorption onto a semiconductor surface, a high molar absorption coefficient (43 700 L mol-1 cm-1) and favorable alignment of energy levels and provided a long lifetime of electrons (17.8 ms) in the TiO2 photoanode, it was found that the efficiency of hypericin-sensitized solar cells was very low, only 0.0245%. We suggest that this inefficiency originated from a low injection of electrons into the conduction band of TiO2. This conclusion is supported by the density functional theory calculations which revealed a low electron density in the anchoring groups of electronically excited hypericin. The results of this work could be valuable not only in the photovoltaic aspect, but also for application of hypericin in medicine in photodynamic therapy.


Assuntos
Corantes/química , Fontes de Energia Elétrica , Elétrons , Perileno/análogos & derivados , Energia Solar , Teoria da Densidade Funcional , Perileno/química , Titânio/química
8.
J Environ Sci (China) ; 84: 59-68, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31284917

RESUMO

A catalyst based on mixed V-Ni oxides supported on TiO2 (Ni-V/TiO2) was obtained using the sol-gel method. Its catalytic performance relative to dichloromethane (DCM) degradation was investigated. Characterization and analysis were conducted using transmission electron microscopy, H2 temperature-programmed reduction, pyridine-Fourier transform infrared spectroscopy (FTIR) characterization, and X-ray diffraction. Results showed that the original hollow anatase structure of pure TiO2 was well-maintained after Ni-V loading. The loading of NiO-VOx not only significantly improved the stability of pure TiO2 but also inhibited the formation of the by-product monochloromethane (MCM). Among the series of Ni-V/TiO2 catalysts, 4%Ni-V/TiO2 possessed the highest catalytic activity, with 90% DCM conversion at only 203°C. No by-products and no significant changes in the catalytic activity were observed during combustion of DCM after 100 hr of a continuous stability test. Furthermore, thermogravimetric analysis (O2-TG) and energy dispersive spectrometer (EDS) characterization of the used 4%Ni-V/TiO2 catalyst revealed that no coke deposition or chlorine species could be detected on the catalyst surface.


Assuntos
Cloreto de Metileno/química , Titânio/química , Catálise , Oxirredução
9.
J Photochem Photobiol B ; 197: 111515, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31255939

RESUMO

An extraordinary arrangement of research is as yet going on in the area of orthopedic implants advancement to determine different issues being looked by the engineering today. In spite of a few detriments of the orthopedic metallic inserts, they keep on being utilized, essentially as a result of their unrivaled mechanical properties. We investigated the conceivable utilization of silicon carbide (SiC) as a nano-ceramic covering material of titanium (Ti)-based all out femoral substitution implants. The thought is to keep wear garbage arrangement from the delicate titanium exterior. Silicon carbide is a hard and firmly holding bio-ceramic surface substance, and in light of these physico-chemical properties, it isn't actually degradable, just like the case with apatite (HA). To improve cytocompatibility and osseous-integration, we deposited anodized titanium nanotubes (TiO2) inserts, by electrochemical deposition method (EDM), with silicon carbide (SiC) with apatite (SiC@HA). The deposition was affirmed by SEM, while phase composition properties were assessed by XRD. Calcium affidavit, osteocalcin creation, and articulation of bone genes were essentially higher in rodent osteoblast cell culture on SiC@HA-covered anodized titanium nanotubes than in cells cultured on uncoated anodized titanium nanotubes. Implantation into rodent femurs likewise demonstrated that the SiC@HA-covered substance had unrivaled osseous-integration movement in correlation with that of customary inserts, as evaluated by in vivo tomography and histology. Therefore, anodized titanium nanotubes covered with SiC@HA holds guarantee as an orthopedic implant substance.


Assuntos
Regeneração Óssea , Compostos Inorgânicos de Carbono/química , Materiais Revestidos Biocompatíveis/química , Durapatita/química , Nanopartículas/química , Compostos de Silício/química , Titânio/química , Animais , Regeneração Óssea/efeitos dos fármacos , Osso e Ossos/metabolismo , Osso e Ossos/patologia , Adesão Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Revestidos Biocompatíveis/uso terapêutico , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Fraturas do Fêmur/terapia , Regulação da Expressão Gênica/efeitos dos fármacos , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteocalcina/metabolismo , Próteses e Implantes , Ratos
10.
J Photochem Photobiol B ; 197: 111555, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31326844

RESUMO

A series of heterocyclic donor-acceptor systems were synthesized and well characterized by using 1H, 13C NMR, FT-IR, and elemental analysis. They were designed to investigate the effect of thiophene and cyanoacrylic acid number units on the thermal, optical, electrochemical and finally photovoltaic properties of dye-sensitized solar cells prepared with the selected compounds. The effect of chemical structure on their properties was demonstrated. They showed the beginning of thermal decomposition between 230 and 270 °C. The compounds absorbed the radiation in the range of 300-500 nm or 200-400 nm. They were electrochemically active and varied in energy band gap from 3.40 to 1.58 eV. Additionally, their optimized geometry, HOMO-LUMO levels, ionization potential, and electron affinity were evaluated using density functional theory. The photovoltaic devices based on TiO2 sensitized with the obtained molecules exhibited low power conversion efficiency, which was the highest for the device containing the symmetrical molecule with bithiophene structure. Under co-sensitization, the cell made of the same compound gave significant enhancement of efficiency of 6.3% being higher to that of the individual device prepared from dye N719 (5.75%). Moreover, the effects of immersion time of TiO2 electrode in the dye solution and co-sensitization methods were tested. The surface morphology of photoanode was investigated using atomic force microscopy.


Assuntos
Corantes/química , Cianoacrilatos/química , Energia Solar , Cianoacrilatos/síntese química , Teoria da Densidade Funcional , Fontes de Energia Elétrica , Microscopia de Força Atômica , Oxirredução , Titânio/química
11.
Am J Orthod Dentofacial Orthop ; 156(1): 75-86, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31256844

RESUMO

INTRODUCTION: Maintaining tooth anchorage during orthodontic treatment has challenged orthodontists and threatening the success of some orthodontic therapy. The objective of this study was to evaluate the effect of local administration of simvastatin on orthodontic tooth movement. METHODS: Nickel-titanium coil springs were used to induce orthodontic tooth movement in 10 white New Zealand rabbits for 21 days. A split-mouth design was implemented where one mandibular quadrant received local administration of simvastatin and the corresponding mandibular quadrant received control vehicle solution on a weekly basis. Magnitudes of tooth movement were measured on 3-dimensional models of the experimental teeth. Animals were killed at the end of the experimental period to allow histomorphometric analysis of alveolar bone modeling. RESULTS: The total magnitude of tooth movement in the quadrant receiving simvastatin was significantly less than that in the quadrant receiving control vehicle solution. Local administration of simvastatin resulted in a significant percentage of inhibition of tooth movement of 39.8 ± 22.6%. Histomorphometric analysis revealed a significant reduction in the numbers of osteoclasts and areas of active bone-resorptive lacunae hindering bone resorption processes in the quadrant receiving simvastatin. CONCLUSIONS: Local administration of simvastatin can reduce the rate and magnitude of orthodontic tooth movement. Moreover, local administration of simvastatin diminishes bone resorption processes associated with orthodontic tooth movement reducing the number of osteoclasts and the subsequent area of active bone resorption.


Assuntos
Reabsorção Óssea/patologia , Osteoclastos/efeitos dos fármacos , Sinvastatina/administração & dosagem , Sinvastatina/antagonistas & inibidores , Técnicas de Movimentação Dentária/métodos , Perda do Osso Alveolar/diagnóstico por imagem , Perda do Osso Alveolar/patologia , Animais , Remodelação Óssea/efeitos dos fármacos , Reabsorção Óssea/diagnóstico por imagem , Masculino , Mandíbula/irrigação sanguínea , Mandíbula/efeitos dos fármacos , Mandíbula/patologia , Modelos Animais , Níquel/química , Aparelhos Ortodônticos , Fios Ortodônticos , Osteoclastos/patologia , Coelhos , Titânio/química , Técnicas de Movimentação Dentária/instrumentação
12.
Niger J Clin Pract ; 22(7): 926-931, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31293256

RESUMO

Background: This study was performed to evaluate the amount of apically extruded debris removed from a root canal filled with cold lateral condensation (CLC), and warm vertical compaction (WVC) techniques, using b or a phase gutta-percha with AH-Plus (Dentsply DeTrey, Konstanz, Germany) or Resilon (Resilon Research LLC, Madison, WI) with RealSeal SE (SybronEndo, Amersfoort, The Netherlands). Materials and Methods: About 100 human incisor teeth were prepared with a #25.06 NiTi rotary system and divided into five groups according to the filling material used: Group 1: CLC (gutta-percha, AH-Plus); Group 2: WVC (b phase gutta-percha, AH-Plus); Group 3: WVC (a phase gutta-percha, AH-Plus); Group 4: CLC (Resilon, RealSeal SE); and Group 5: WVC (Resilon, RealSeal SE). Extruded debris during the retreatment procedure was collected in preweighed Eppendorf tubes. The times required for retreatment were recorded. Results: The amount of debris extrusion was significantly greater with WVC than CLC in the gutta-percha and Resilon groups (P < 0.001). Using a phase gutta-percha resulted in significantly more debris extrusion than b phase gutta-percha (P < 0.001). In the WVC groups, Resilon caused significantly more debris extrusion than gutta-percha (P < 0.05). Retreatment was faster for CLC than WVC (P < 0.05). Conclusions: In the retreatment procedure, the amount of apically extruded debris and retreatment duration were dependent on the type of obturation material and technique used.


Assuntos
Cavidade Pulpar/cirurgia , Guta-Percha/química , Materiais Restauradores do Canal Radicular/química , Preparo de Canal Radicular/instrumentação , Preparo de Canal Radicular/métodos , Tratamento do Canal Radicular/instrumentação , Ligas Dentárias/química , Humanos , Níquel , Retratamento , Materiais Restauradores do Canal Radicular/efeitos adversos , Obturação do Canal Radicular/métodos , Titânio/química , Ápice Dentário/patologia
13.
Food Chem ; 298: 124981, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260993

RESUMO

Development of an effective sensor for sensing glucose in commercially available "sugar free" food products is important as people are becoming diabetic health conscious. Although multi-walled carbon nanotubes (MWCNTs) possess interesting electrical properties, their hydrophobic nature limits their applications. Their hydrophilicity can be improved through modification. In the present study, Inulin, that was isolated from Allium sativum L. using hot water diffusion and incorporated with titanium dioxide (TiO2), was used for the modification of MWCNTs. The as-synthesized MWCNT-Inulin-TiO2 bio-nanocomposite immobilized with glucose oxidase (GOx) was incorporated into the carbon paste matrix and was utilized for the sensing of glucose in food products. Differential pulse voltammetric studies revealed that the fabricated electrode demonstrated good linear range (1.6 nM to 1 µM) and was sensitive to nanomolar concentrations of glucose with a very low limit of detection up to 0.82 nM and exhibited a long term stability of 150 days.


Assuntos
Eletrodos , Análise de Alimentos/métodos , Glucose Oxidase/química , Glucose/análise , Nanocompostos/química , Enzimas Imobilizadas/química , Análise de Alimentos/instrumentação , Alho/química , Glucose/química , Inulina/química , Limite de Detecção , Nanotubos de Carbono/química , Sensibilidade e Especificidade , Titânio/química
14.
Chem Commun (Camb) ; 55(67): 9927-9930, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31334708

RESUMO

Tyrosine phosphorylation regulates the upstream signaling pathway but accounts for less than 0.1% of total phosphorylation in human cells. Herein, molecularly imprinted mesoporous materials were first synthesized to recognize the phosphorylated tyrosine residue from other phosphorylated residues.


Assuntos
Epitopos , Impressão Molecular , Nanopartículas/química , Compostos Organofosforados/química , Dióxido de Silício/química , Tirosina/metabolismo , Adsorção , Cinética , Fosfopeptídeos/química , Fosforilação , Porosidade , Titânio/química
16.
Int J Nanomedicine ; 14: 4133-4144, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31239672

RESUMO

Background: Although titanium dioxide nanotubes (TNTs) had great potential to promote osteogenesis, their weak bonding strength with titanium substrates greatly limited their clinical application. Purpose: The objective of this study was to maintain porosity and improve the stability of TNT coatings by preparing some micro-patterned mesoporous/nanotube (MP/TNT) structures via a photolithography-assisted anodization technology. Methods: The adhesion strength of different coatings was studied by ultrasonic cleaning machine and scratch tester. The early adhesion, spreading, proliferation and differentiation of MC3T3-E1 cells on different substrates were investigated in vitro by fluorescent staining, CCK8, alkaline phosphatase activity, mineralization and polymerase chain reaction assays, respectively. Results: Results of ultrasonic and scratch assays showed that the stability of TNTs (especially 125 nm) was significantly improved after being patterned with MP structures. In vitro cell assays further demonstrated that the insertion of MP structure into 125 nm TNT coating, which was denoted as MP125, could effectively improve the early adhesion, spreading and proliferation of surface MC3T3-E1 cells without damaging their osteogenic differentiation. Conclusion: We determined that the MP/TNT patterned samples (especially MP125) have excellent stability and osteogenesis properties, and may have better clinical application prospects.


Assuntos
Nanotubos/química , Osteogênese , Titânio/química , Adsorção , Fosfatase Alcalina/metabolismo , Animais , Adesão Celular/genética , Diferenciação Celular/genética , Linhagem Celular , Proliferação de Células/genética , Forma Celular/genética , Sobrevivência Celular/genética , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Fluorescência , Regulação da Expressão Gênica , Humanos , Camundongos , Minerais/metabolismo , Osteocalcina/genética , Osteocalcina/metabolismo , Osteogênese/genética , Osteopontina/genética , Osteopontina/metabolismo , Porosidade , Água/química
17.
Environ Pollut ; 251: 975-983, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31234265

RESUMO

Efficient containment and capture of uranium (U(VI)) from aqueous solution is an essential component to ensure socially and environmentally sustainable development. Herein, the three-dimensional graphene/titanium dioxide composite (3D GA/TiO2) was synthesized and applied as an effective adsorbent to remove U(VI) from wastewater as a function of contact time, temperature, pH and ion strength. The 3D GA/TiO2 material was characterized by X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The batch experiments results indicated that the adsorption of U(VI) on materials were fitted with the pseudo-second order kinetics and Langmuir models. More specifically, 3D GA/TiO2 (441.3 mg/g) was observed to outperform the GO (280.0 mg/g), rGO (140.9 mg/g) and TiO2 (98.5 mg/g) at pH 5.0, which was attributable to the excellent cooperative effects. Furthermore, XPS analyses and DFT calculations confirmed the formation of surface complexes between oxygen-containing group and U(VI) with the U-O bonds length of 2.348 Š(U-O1) and 2.638 Š(U-O2). Meanwhile, the adsorption energy was calculated to be 1.60 eV, which showed a very strong chemisorption during the interaction process. It is believed that the 3D GA/TiO2 revealed good removal performance for uranyl ions, which showed a great potential application to control the nuclear industrial pollution.


Assuntos
Recuperação e Remediação Ambiental/métodos , Grafite/química , Titânio/química , Urânio/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Teoria da Densidade Funcional , Concentração Osmolar , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
18.
J Environ Sci (China) ; 83: 183-194, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31221381

RESUMO

The photocatalytic activity of Fe-doped TiO2 nanoparticles is significantly increased by an acid-treatment process. The photocatalyst nanoparticles were prepared using sol-gel method with 0.5 mol% ratio of Fe:Ti in acidic pH of 3. The nanoparticles were structurally characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). It was observed that the photocatalytic activity suffered from an iron oxide contaminating layer deposited on the surface of the nanoparticles. This contamination layer was removed using an HCl acid-treatment process. The photocatalytic activity using 500 mg/L of Fe0.5-TiO2 in a 10 mg/L of phenol solution increased significantly from 33% to 57% (about 73% increase in the performance), within 90 min of reaction time under visible light irradiation. This significant improvement was achieved by removing the iron oxide contamination layer from the surface of the nanoparticles and adjusting pH to mild acidic and basic pHs.


Assuntos
Modelos Químicos , Fenol/química , Processos Fotoquímicos , Catálise , Luz , Fenóis , Espectroscopia Fotoeletrônica , Espectrometria por Raios X , Titânio/química , Difração de Raios X
19.
Int J Nanomedicine ; 14: 3439-3454, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190802

RESUMO

Objective: The microbial, physico-chemical and optical corruptions threaten a variety of foods and drugs and consequently the human biological safety and its accessible resources. The humanbeing's tendency towards bio-based materials and natural plant-extracts led to an increase in the usage of antimicrobial biocomposites based on medicinal herbs. Miswak (Salvadora persica L.) extract (SPE) has been proved effective for its antimicrobial and other biological activities. Therefore, in this study, titanium dioxide (TiO2) nanoparticles (TONP) and SPE were applied to fabricate antimicrobial carboxymethyl cellulose (Na-CMC) based bio-nanocomposites which would simultaneously promote some thermo-physical and barrier properties. Methods: CMC-neat film (C1), CMC/TONP-2% (C2) and CMC/TONP-2% with 150, 300 and 450 mg/mL SPE (SPE150, SPE30 and SPE450, respectively) were fabricated. The physical and mechanical properties; elemental mapping analysis (MAP), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA-DTG); fourier transform infrared (FTIR), energy-dispersive X-ray (EDX) and UV-vis spectroscopies were done to further validate the results. Results: Addition of TONP (2%) improved the blocking of UV light at 280 nm while SPE-containing nanocomposites completely blocked it. FTIR, XRD and SEM confirmed the formation of homogeneous films and high miscibility of applied materials. TONP led to an increase in Young's modulus (YM) and stress at break (SB) while SPE decreased them and enhanced the elongation to break (EB) (flexibility) of the active nanocomposites. Compared to CMC-film, the thermo-gravimetric analysis (TGA-DTG) showed a higher thermal stability for CMC/TONP and CMC/TONP/SPE nanocomposites. The EDX spectroscopy and elemental mapping analysis (MAP) proved the existence and well-distributedness of Na, K, Cl, S, Ti, F and N elements in SPE-activated nanocomposites. The pure SPE and SPE-activated nanocomposites showed a favorable antimicrobial activity against both gram-positive (Staphylococcus aureus) and negative (Escherichia coli) bacteria. Conclusion: The CMC-TiO2-SPE nanocomposites were homogeneously produced. Combination of TiO2 nanoparticles and dose-dependent SPE led to an improvement of thermal stability, and high potential in antimicrobial and UV-barrier properties. These results can generally highlight the role of the fabricated antimicrobial bio-nanocomposites as a based for different applications especially in food/drug packaging or coating.


Assuntos
Antibacterianos/farmacologia , Nanocompostos/química , Nanopartículas/química , Extratos Vegetais/farmacologia , Salvadoraceae/química , Temperatura Ambiente , Titânio/química , Elementos , Humanos , Umidade , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Permeabilidade , Espectrofotometria Ultravioleta , Staphylococcus aureus/efeitos dos fármacos , Vapor , Termogravimetria , Difração de Raios X
20.
Int J Nanomedicine ; 14: 3583-3600, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190813

RESUMO

Purpose: This study aimed to decorate the surface of TiO2 nanotubes (TiO2 NTs) grown on medical grade Ti-6Al-4V alloy with an antimicrobial layer of nano zinc oxide particles (nZnO) and then determine if the antimicrobial properties were maintained with a final layer of nano-hydroxyapatite (HA) on the composite. Methods: The additions of nZnO were attempted at three different annealing temperatures: 350, 450 and 550 °C. Of these temperatures, 350°C provided the most uniform and nanoporous coating and was selected for antimicrobial testing. Results: The LIVE/DEAD assay showed that ZnCl2 and nZnO alone were >90% biocidal to the attached bacteria, and nZnO as a coating on the nanotubes resulted in around 70% biocidal activity. The lactate production assay agreed with the LIVE/DEAD assay. The concentrations of lactate produced by the attached bacteria on the surface of nZnO-coated TiO2 NTs and ZnO/HA-coated TiO2 NTs were 0.13±0.03 mM and 0.37±0.1 mM, respectively, which was significantly lower than that produced by the bacteria on TiO2 NTs alone, 1.09±0.30 mM (Kruskal-Wallis, P<0.05, n=6). These biochemical measurements were correlated with electron micrographs of cell morphology and cell coverage on the coatings. Conclusion: nZnO on TiO2 NTs was a stable and antimicrobial coating, and most of the biocidal properties remained in the presence of nano-HA on the coating.


Assuntos
Anti-Infecciosos/farmacologia , Materiais Revestidos Biocompatíveis/química , Durapatita/química , Nanotubos/química , Staphylococcus aureus/efeitos dos fármacos , Titânio/química , Óxido de Zinco/química , Zinco/farmacologia , Anti-Infecciosos/química , Preparações de Ação Retardada/química , Diálise , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Nanopartículas/química , Nanopartículas/ultraestrutura , Nanotubos/ultraestrutura , Propriedades de Superfície
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