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1.
J Vis Exp ; (162)2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32894264

RESUMO

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles (NPs) can accelerate and control the selectivity of a variety of molecular transformations. This opens possibilities for the use of visible or near-IR light as a sustainable input to drive and control reactions when plasmonic nanoparticles supporting LSPR excitation in these ranges are employed as catalysts. Unfortunately, this is not the case for several catalytic metals such as palladium (Pd). One strategy to overcome this limitation is to employ bimetallic NPs containing plasmonic and catalytic metals. In this case, the LSPR excitation in the plasmonic metal can contribute to accelerate and control transformations driven by the catalytic component. The method reported herein focuses on the synthesis of bimetallic silver-palladium (Ag-Pd) NPs supported on ZrO2 (Ag-Pd/ZrO2) that acts as a plasmonic-catalytic system. The NPs were prepared by co-impregnation of corresponding metal precursors on the ZrO2 support followed by simultaneous reduction leading to the formation of bimetallic NPs directly on the ZrO2 support. The Ag-Pd/ZrO2 NPs were then used as plasmonic catalysts for the reduction of nitrobenzene under 425 nm illumination by LED lamps. Using gas chromatography (GC), the conversion and selectivity of the reduction reaction under the dark and light irradiation conditions can be monitored, demonstrating the enhanced catalytic performance and control over selectivity under LSPR excitation after alloying non-plasmonic Pd with plasmonic metal Ag. This technique can be adapted to a wide range of molecular transformations and NPs compositions, making it useful for the characterization of the plasmonic catalytic activity of different types of catalysis in terms of conversion and selectivity.


Assuntos
Ligas/química , Nanopartículas Metálicas/química , Paládio/química , Prata/química , Ligas/síntese química , Catálise , Luz , Nitrobenzenos/química , Oxirredução , Ressonância de Plasmônio de Superfície , Zircônio/química
2.
Int J Nanomedicine ; 15: 6137-6152, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32884268

RESUMO

Background: Beyond clinical atherosclerosis imaging of vessel stenosis and plaque morphology, early detection of inflamed atherosclerotic lesions by molecular imaging could improve risk assessment and clinical management in high-risk patients. To identify inflamed atherosclerotic lesions by molecular imaging in vivo, we studied the specificity of our radiotracer based on maleylated (Mal) human serum albumin (HSA), which targets key features of unstable atherosclerotic lesions. Materials and Methods: Mal-HSA was radiolabeled with a positron-emitting metal ion, zirconium-89 (89Zr4+). The targeting potential of this probe was compared with unspecific 89Zr-HSA and 18F-FDG in an experimental model of atherosclerosis (Apoe-/- mice, n=22), and compared with wild-type (WT) mice (C57BL/6J, n=21) as controls. Results: PET/MRI, gamma counter measurements, and autoradiography showed the accumulation of 89Zr-Mal-HSA in the atherosclerotic lesions of Apoe-/- mice. The maximum standardized uptake values (SUVmax) for 89Zr-Mal-HSA at 16 and 20 weeks were 26% and 20% higher (P<0.05) in Apoe-/- mice than in control WT mice, whereas no difference in SUVmax was observed for 18F-FDG in the same animals. 89Zr-Mal-HSA uptake in the aorta, as evaluated by a gamma counter 48 h postinjection, was 32% higher (P<0.01) for Apoe-/- mice than in WT mice, and the aorta-to-blood ratio was 8-fold higher (P<0.001) for 89Zr-Mal-HSA compared with unspecific 89Zr-HSA. HSA-based probes were mainly distributed to the liver, spleen, kidneys, bone, and lymph nodes. The phosphor imaging autoradiography (PI-ARG) results corroborated the PET and gamma counter measurements, showing higher accumulation of 89Zr-Mal-HSA in the aortas of Apoe-/- mice than in WT mice (9.4±1.4 vs 0.8±0.3%; P<0.001). Conclusion: 89Zr radiolabeling of Mal-HSA probes resulted in detectable activity in atherosclerotic lesions in aortas of Apoe-/- mice, as demonstrated by quantitative in vivo PET/MRI. 89Zr-Mal-HSA appears to be a promising diagnostic tool for the early identification of macrophage-rich areas of inflammation in atherosclerosis.


Assuntos
Aterosclerose/diagnóstico por imagem , Maleatos/química , Imagem Molecular/métodos , Radioisótopos , Albumina Sérica Humana/química , Zircônio , Animais , Aorta/diagnóstico por imagem , Aorta/patologia , Aterosclerose/patologia , Autorradiografia , Modelos Animais de Doenças , Feminino , Fluordesoxiglucose F18 , Humanos , Marcação por Isótopo , Macrófagos/patologia , Imagem por Ressonância Magnética , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoE , Sondas Moleculares/química , Sondas Moleculares/farmacocinética , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/patologia , Tomografia por Emissão de Pósitrons , Radioisótopos/química , Radioisótopos/farmacocinética , Compostos Radiofarmacêuticos/química , Distribuição Tecidual , Zircônio/química , Zircônio/farmacocinética
3.
Int J Nanomedicine ; 15: 5061-5072, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764936

RESUMO

Purpose: Zirconia is one of the most promising implant materials due to its favorable physical, mechanical and biological properties. However, until now, we know little about the mechanism of osseointegration on zirconia. The purpose of this study is to evaluate the effect of Syndecan (Sdc) on osteoblastic cell (MC3T3-E1) adhesion and proliferation onto zirconia materials. Materials and Methods: The mirror-polished disks 15 mm in diameter and 1.5 mm in thick of commercial pure titanium (CpTi), 3mol% yttria-stabilized tetragonal zirconia polycrystalline (3Y-TZP) and nano-zirconia (NanoZr) are used in this study. MC3T3-E1 cells were seeded onto specimen surfaces and subjected to RNA interference (RNAi) for Syndecan-1, Syndecan-2, Syndecan-3, and Syndecan-4. At 48h post-transfection, the cell morphology, actin cytoskeleton, and focal adhesion were observed using scanning electron microscopy or laser scanning confocal fluorescence microscopy. At 24h and 48h post-transfection, cell counting kit-8 (CCK-8) assay was used to investigate cell proliferation. Results: The cell morphology of MC3T3-E1 cells on CpTi, 3Y-TZP, and NanoZr changed into abnormal shape after gene silencing of Syndecan. Among the Syndecan family, Sdc-2 is responsible for NanoZr-specific morphology regulation, via maintenance of cytoskeletal conformation without affecting cellular attachment. According to CCK-8 assay, Sdc-2 affects the osteoblastic cell proliferation onto NanoZr. Conclusion: Within the limitation of this study, we suggest that Syndecan affects osteoblastic cell adhesion on CpTi, 3Y-TZP, and NanoZr. Sdc-2 might be an important heparin-sensitive cell membrane regulator in osteoblastic cell adhesion, specifically on NanoZr, through the organization of actin cytoskeleton and affects osteoblastic cell proliferation.


Assuntos
Osseointegração/fisiologia , Osteoblastos/citologia , Osteoblastos/fisiologia , Sindecanas/metabolismo , Citoesqueleto de Actina/efeitos dos fármacos , Animais , Adesão Celular/fisiologia , Membrana Celular/efeitos dos fármacos , Proliferação de Células/fisiologia , Células Cultivadas , Camundongos , Microscopia Eletrônica de Varredura , Osseointegração/genética , Propriedades de Superfície , Sindecana-2/genética , Sindecana-2/metabolismo , Sindecanas/genética , Titânio/química , Ítrio/química , Zircônio/química
4.
PLoS One ; 15(6): e0234524, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32579584

RESUMO

The purpose of this study was to evaluate the adherence of streptococci to disks of titanium (commercially pure titanium: CpTi) and zirconia (tetragonal zirconia polycrystals: TZP). CpTi and yttria-stabilized TZP disks with a mirror-polished surface were used as specimens. The arithmetic mean surface roughness (Ra and Sa) and the surface wettability of the experimental specimens were measured. For analyzing the outermost layer of the experimental specimens, X-ray photoelectron spectroscopy (XPS) analysis was performed. Streptococcus sanguinis, S. gordonii, S. oralis, and S. mutans were used as streptococcal bacterial strains. These bacterial cultures were grown for 24 h on CpTi and TZP. The number of bacterial adhesions was estimated using an ATP-bioluminescent assay, and scanning electron microscope (SEM) observation of the adhered bacterial specimens was performed. No significant differences in surface roughness or wettability were found between CpTi and TZP. In XPS analyses, outermost layer of CpTi included Ti0 and Ti4+, and outermost layer of TZP included Zr4+. In the cell adhesion assay, the adherences of S. sanguinis, S. gordonii, and S. oralis to TZP were significantly lower than those to CpTi (p < 0.05); however, significant difference was not observed for S. mutans among the specimens. The adherence to CpTi and TZP of S. mutans was significantly lower than that of S. sanguinis, S. gordonii, and S. oralis. These results were confirmed by SEM. S. sanguinis, S. gordonii, and S. oralis adhered less to TZP than to CpTi, but the adherence of S. mutans was similar to both surfaces. S. mutans was less adherent compare with the other streptococci tested in those specimens.


Assuntos
Aderência Bacteriana/efeitos dos fármacos , Streptococcus sanguis/efeitos dos fármacos , Titânio/química , Zircônio/química , Teste de Materiais , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Streptococcus sanguis/química , Streptococcus sanguis/ultraestrutura , Propriedades de Superfície/efeitos dos fármacos , Ítrio/química
5.
Proc Natl Acad Sci U S A ; 117(25): 14299-14305, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32513701

RESUMO

The Lower Cretaceous Huajiying Formation of the Sichakou Basin in northern Hebei Province, northern China contains key vertebrate taxa of the early Jehol Biota, e.g., Protopteryx fengningensis, Archaeornithura meemannae, Peipiaosteus fengningensis, and Eoconfuciusornis zhengi This formation arguably documents the second-oldest bird-bearing horizon, producing the oldest fossil records of the two major Mesozoic avian groups Enantiornithes and Ornithuromorpha. Hence, precisely determining the depositional ages of the Huajiying Formation would advance our understanding of the evolutionary history of the Jehol Biota. Here we present secondary ion mass spectrometry (SIMS) U-Pb zircon analysis results of eight interbedded tuff/tuffaceous sandstone samples from the Huajiying Formation. Our findings, combined with previous radiometric dates, suggest that the oldest enantiornithine and ornithuromorph birds in the Jehol Biota are ∼129-131 Ma, and that the Jehol Biota most likely first appeared at ∼135 Ma. This expands the biota's temporal distribution from late Valanginian to middle Aptian with a time span of about 15 My.


Assuntos
Biota , Aves/classificação , Chumbo/química , Silicatos/química , Zircônio/química , Animais , Evolução Biológica , China , Fósseis , Geologia , Filogenia , Espectrometria de Massa de Íon Secundário
6.
Food Chem ; 329: 127210, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512388

RESUMO

In this study, a novel, easy, rapid and green zirconium nanoparticles (Zr-NPs) based dispersive solid phase extraction (DSPE) method is presented for the precise and sensitive determination of selenium by slotted quartz tube-flame atomic absorption spectrophotometry (SQT-FAAS). Influential parameters of the extraction procedure were optimized by altering one parameter while keeping the other parameters constant. The optimum conditions were selected as 10 mg of Zr-NPs, 75 s vortex period, and 200 µL of concentrated HCl for 30 mL of sample/standard solution. The linear range of the developed method was found to be between 25 and 100 µg/L, and the respective limits of detection and quantification were 5.3 and 18 µg/L. About 415 folds enhancement in detection power was achieved by the optimized method relative to the conventional FAAS. Green tea samples were spiked and used for recovery experiments and the results obtained were between 92 and 102%.


Assuntos
Nanopartículas Metálicas/química , Selênio/análise , Espectrofotometria Atômica/métodos , Chá/química , Zircônio/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Reprodutibilidade dos Testes , Selênio/isolamento & purificação , Extração em Fase Sólida
7.
Artigo em Inglês | MEDLINE | ID: mdl-32532181

RESUMO

Diesel oil spills in marine environments pose a severe threat to both aquatic and terrestrial ecosystems. Photocatalysis is an environment-friendly method for marine oil remediation; however, its practical usage is limited due to several issues. In this study, we demonstrate the enhanced efficacy of doped CuO/ZrO2 photocatalyst at degrading marine diesel in comparison to undoped ZrO2. The photocatalysts were prepared using co-precipitation method, and their physical and chemical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and ultraviolet-visible spectroscopy (UV-Vis). XRD analysis showed that the photocatalytic crystallite size of ZrO2 and CuO/ZrO2 was 28.80 nm and 40.32 nm, respectively. Both catalysts exhibited stable crystalline forms. UV-Vis analysis showed that doping of ZrO2 with CuO significantly reduced its band gap from 4.61 eV to 1.18 eV, thus enhancing the utilization of visible light. The effect of catalyst dosage, doping ratio, and initial diesel concentration on the degradation rate of diesel was investigated by performing single-factor experiments. The optimization experiment results showed that 96.96% of diesel could be degraded under visible light. This study laid an experimental foundation for expanding the practical applications of photocatalytic technology.


Assuntos
Cobre/química , Luz , Nanocompostos/química , Poluição por Petróleo/análise , Poluentes Químicos da Água/análise , Zircônio/química , Catálise , Ecossistema , Recuperação e Remediação Ambiental , Modelos Teóricos , Oxirredução , Água do Mar/química
8.
Chemosphere ; 258: 127370, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554019

RESUMO

Porous luffa plant fibre (LF) was grafted with Fe and Zr, and the ability of the fabricated adsorbents to remove arsenate (As(V)) from water was investigated in batch and column adsorption experiments. The Langmuir adsorption capacity (mg g-1) at pH 7 of LF was found to be 0.035, which increased to 2.55 and 2.89 after being grafted with Fe (FLF-3) and Zr (ZLF-3), respectively. Grafting with Fe and Zr increased the zeta potential and zero point of charge (ZPC) of LF (from pH 3.9 to 7.4 for Fe grafting and to 7.6 for Zr grafting), due to chemical bonding of the metals, possibly with the hydroxyl and carboxylic groups in LF as indicated in FTIR peaks. Zeta potential and ZPC decreased after As adsorption owing to inner-sphere complexation mechanism of adsorption. The increase of pH from 3 to 10 progressively reduced the adsorbents' adsorption capacity. Co-existing anions weakened the As(V) removal efficiency in the order, PO43- > SiO32- > CO32- > SO42-. Adsorption kinetics data fitted well to the Weber and Morris model, which revealed initial fast and subsequent slow rates of intra-particle As diffusion into the bigger pores and smaller pores, respectively. Column adsorption data fitted well to the Thomas model with the predicted adsorption capacities in the same order as in the batch adsorption experiment (ZLF-3 > FLF-3 > LF).


Assuntos
Arseniatos/análise , Água Potável/química , Ferro/química , Luffa/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Zircônio/química , Adsorção , Água Potável/normas , Concentração de Íons de Hidrogênio , Cinética
9.
Niger J Clin Pract ; 23(6): 792-797, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32525113

RESUMO

Background: There is no information about the shear bond strengths (SBS) of zirconia ceramic to primary tooth dentin. Aim: To investigate the effect of different surface treatments and cements on the shear bond strength (SBS) of zirconia ceramic to primary tooth dentin. Materials and Methods: Prepared zirconia bars were distributed into four groups according to surface treatment procedure: control, sandblasting, CoJet and hot etching. The zirconia specimens in each group were further divided into subgroups according to cement (n = 13): self-adhesive resin (Rely-X Unicem), resin-modified glass ionomer (Ketac-Cem Plus), and universal bioactive (BioCem). Zirconia specimens were bonded to the primary tooth dentin surface by cement. SBS was measured, and the data were subjected to two-way ANOVA and Tukey's tests. Results: Statistical differences were observed in the surface treatment procedures for Rely-X Unicem (P < 0.05), but no statistically significant differences were found in the sandblasting, CoJet and hot-etching groups for Ketac-Cem Plus (P > 0.05). For BioCem, the SBS value for the hot etching group was significantly lower than those for the CoJet and sandblasting groups (P < 0.05). The SBS values for the Rely-X Unicem subgroups (sandblasting, CoJet and hot etching) were significantly higher than those for the other cements (P < 0.05). Conclusion: The bond strength of zirconia ceramic to primary tooth dentin is affected by surface treatments and cements.


Assuntos
Cerâmica/química , Colagem Dentária , Dentina , Cimentos de Resina/química , Resistência ao Cisalhamento , Dente Decíduo , Zircônio/química , Resinas Acrílicas , Adesivos , Cimentos de Ionômeros de Vidro , Humanos , Teste de Materiais , Dióxido de Silício , Propriedades de Superfície
10.
Chemosphere ; 255: 126950, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32380266

RESUMO

Metal-modified carbon materials have been widely used for fluoride removal, but the traditional impregnation by soaking method suffers from low loading of metals and substantial use of chemicals. This study proposed a new approach to prepare zirconium modified activated carbon fibres (Zr-ACF) by a drop-coating method. Using the same amount of chemicals, the drop-coating method yielded a 5.5 times higher fluoride adsorption capacity than the soaking method due to more effective loading of Zr(IV) onto ACF. The effects of various preparation conditions, including the addition of a complexing agent (oxalic acid) and Zr/ACF mass ratio (0.2-1), were investigated. Zr-ACF prepared by drop-coating was characterised by SEM and BET, and the functional groups involved in the anchoring of Zr(IV) on ACF and the adsorption of fluoride onto Zr-ACF were identified by FTIR and XPS. Adsorption experiments at pH between 3 and 11 revealed that ion exchange and electrostatic attraction were the main adsorption mechanisms at different pH levels. Co-existing anions such as CO32-, HCO3- and Cl- had an insignificant negative impact (<5%) on fluoride adsorption capacity while SO42- decreased fluoride adsorption capacity by 11.5%. The adsorption kinetics followed the pseudo-second-order model. The adsorption isotherms followed the Langmuir isotherm model with a maximum fluoride adsorption capacity of 28.50 mg/L at 25 °C, which was higher than other carbon-based materials in the literature. The remarkable improvement of adsorption capacity and reduced chemical consumption demonstrate that Zr-ACF prepared by drop-coating is a promising adsorbent for fluoride removal.


Assuntos
Fluoretos/química , Poluentes Químicos da Água/química , Zircônio/química , Adsorção , Ânions , Fibra de Carbono , Carvão Vegetal , Concentração de Íons de Hidrogênio , Troca Iônica , Cinética , Ácido Oxálico , Água , Purificação da Água/métodos
11.
Chem Commun (Camb) ; 56(40): 5389-5392, 2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32285888

RESUMO

A stable nanoscaled single-excitation ratiometric luminescent pH sensor (MPDB-PCN) over a broad pH range from 2.5 to 8.6 is fabricated through post-synthetic modification of PCN-224 with naphthalimide-derived molecules. Due to the rapid, sensitive and linear response to pH, MPDB-PCN is capable of detecting 3-nitropropionic acid (3-NPA), an acid neurotoxin in food safety, with a low detection limit of 15 µM in sugarcane juice.


Assuntos
Substâncias Luminescentes/química , Estruturas Metalorgânicas/química , Micotoxinas/análise , Nanopartículas/química , Contaminação de Alimentos/análise , Concentração de Íons de Hidrogênio , Limite de Detecção , Neurotoxinas/análise , Nitrocompostos/análise , Extratos Vegetais/análise , Propionatos/análise , Saccharum/química , Espectrometria de Fluorescência/métodos , Zircônio/química
12.
Niger J Clin Pract ; 23(4): 456-463, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32246650

RESUMO

Aims: The purpose of this study was to observe the stresses of all-on-four implant designs in an edentulous mandible in the implant, surrounding bone, and monolithic ceramics. Materials and Methods: In mandibular all-on-four implant models, anterior implants were placed vertically, and posterior implants were differently inclined. On the full-arch fixed prosthetic restoration monolithic zirconia framework, monolithic lithium disilicate was prepared as the superstructure. Model 1M (1M-15.5); posterior implants angled at 15° to the occlusion plane and a cantilever length of 5 mm, Model 2M; (2M-15.9), Model 3M; (3M-30.5), and Model 4M; (4M-30.9) were prepared. A total of 300 N bilateral force was applied at an angle of 30° and oblique to the occlusion plane. Stress values on dental implants, abutments, the surrounding bone, and prosthetic restorations were calculated. Results: The highest stress concentration was observed in the 2nd connector region between the canine and the 1st premolar tooth in the monolithic zirconia frameworks (457.21 MPa). Stress concentration in the cortical bone was 60.93 MPa in posterior implants. Stress was higher in posterior angled implants than straight implants. Stress at posterior angulation increased by 21 MPa in implants angled at 15°. Conclusion: In bilateral loading, the force applied to anterior implants does not have a significant effect on the bone structure. Stress concentration increases in posterior angled implants and surrounding bone. Moreover, stress concentration increases as the length of the cantilever, the weakest part in all-on-four implants, increases. As posterior implant angulation increases, stress concentration level and localization are affected.


Assuntos
Cerâmica/química , Implantes Dentários , Prótese Dentária Fixada por Implante/métodos , Imageamento Tridimensional/métodos , Titânio/química , Zircônio/química , Dente Pré-Molar , Arco Dental/fisiologia , Modelos Dentários , Planejamento de Prótese Dentária , Análise do Estresse Dentário , Análise de Elementos Finitos , Humanos , Mandíbula/fisiologia , Estresse Mecânico
13.
Ecotoxicol Environ Saf ; 196: 110518, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32224367

RESUMO

Nano-sized Fe2Zr2-xWxO7 system was prepared using the Pacini method where x = 0, 0.05, 0.1 and 0.15. All the samples were characterized using chemical analysis, X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), transmission electron microscopy (TEM), UV-vis diffuse reflectance measurements (DRS) and surface area measurements. The undoped Fe2Zr2O7 was crystallised in the cubic fluorite phase as a major phase in addition to rhombohedral phase of Fe2O3 and monoclinic phase of ZrO2 as the minor phases. Meanwhile, single cubic fluorite phase was defined for Fe2Zr0.85W0.15O7 sample. The last has the lowest band gap (1.69 eV) and the highest surface area (106 m2/g). From TEM, the average particle size of the prepared samples was in the range of (3-7 nm). The photocatalytic efficiency of the prepared Fe2Zr2-xWxO7 system was manifested by the degradation of methylene blue and real textile wastewater of blue colour. Ascending degradation efficiency was exhibited with increasing tungsten concentration which is in accordance with their band gap as well as their surface area values. The degradation rate using Fe2Zr0.85W0.15O7 sample obeys the pseudo-first order kinetic at the optimum degradation conditions (1.5 g/L catalyst and pH11). Fe2Zr0.85W0.15O7 showed promising photocatalytic activity for real textile wastewater where the 69% COD removal was obtained under the same conditions used for methylene blue degradation.


Assuntos
Compostos Férricos/química , Luz , Azul de Metileno/análise , Nanopartículas/química , Óxidos/química , Tungstênio/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Zircônio/química , Catálise , Azul de Metileno/química , Azul de Metileno/efeitos da radiação , Tamanho da Partícula , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/efeitos da radiação , Difração de Raios X
14.
Int J Nanomedicine ; 15: 1253-1266, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32161456

RESUMO

Purpose: This study aimed to develop a chelate-free radiolabeled nanoparticle platform for simultaneous positron emission tomography (PET) and magnetic resonance (MR) imaging that provides contrast-enhanced diagnostic imaging and significant image quality gain by integrating the high spatial resolution of MR with the high sensitivity of PET. Methods: A commercially available super-paramagnetic iron oxide nanoparticle (SPION) (Feraheme®, FH) was labeled with the [89Zr]Zr using a novel chelate-free radiolabeling technique, heat-induced radiolabeling (HIR). Radiochemical yield (RCY) and purity (RCP) were measured using size exclusion chromatography (SEC) and radio-thin layer chromatography (radio-TLC). Characterization of the non-radioactive isotope 90Zr-labeled FH was performed by transmission electron microscopy (TEM). Simultaneous PET-MR phantom imaging was performed with different 89Zr-FH concentrations. The MR quantitative image analysis determined the contrast-enhancing properties of FH. The signal-to-noise ratio (SNR) and full-width half-maximum (FWHM) of the line spread function (LSF) were calculated before and after co-registering the PET and MR image data. Results: High RCY (92%) and RCP (98%) of the [89Zr]Zr-FH product was achieved. TEM analysis confirmed the 90Zr atoms adsorption onto the SPION surface (≈ 10% average radial increase). Simultaneous PET-MR scans confirmed the capability of the [89Zr]Zr-FH nano-platform for this multi-modal imaging technique. Relative contrast image analysis showed that [89Zr]Zr-FH can act as a dual-mode T1/T2 contrast agent. For co-registered PET-MR images, higher spatial resolution (FWHM enhancement ≈ 3) and SNR (enhancement ≈ 8) was achieved at a clinical dose of radio-isotope and Fe. Conclusion: Our results demonstrate FH is a highly suitable SPION-based platform for chelate-free labeling of PET tracers for hybrid PET-MR. The high RCY and RCP confirmed the robustness of the chelate-free HIR technique. An overall image quality gain was achieved compared to PET- or MR-alone imaging with a relatively low dosage of [89Zr]Zr-FH. Additionally, FH is suitable as a dual-mode T1/T2 MR image contrast agent.


Assuntos
Imagem por Ressonância Magnética/métodos , Nanopartículas de Magnetita/química , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/química , Cromatografia em Gel , Cromatografia em Camada Delgada , Meios de Contraste/química , Óxido Ferroso-Férrico/química , Humanos , Nanopartículas de Magnetita/uso terapêutico , Imagens de Fantasmas , Radioisótopos/química , Razão Sinal-Ruído , Zircônio/química
15.
Chem Pharm Bull (Tokyo) ; 68(3): 292-297, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32115537

RESUMO

In this study, the adsorption capability of phosphate ion using a novel tri-metals complex hydroxide was evaluated for preventing the eutrophication in water environment. A nickel-aluminum-zirconium complex hydroxide (NAZ) was synthesized using each inorganic sulfate mixing ratio of 0.9 : 1.0 : 0.1 and was calcined at different temperatures. The characteristics of the NAZ were analyzed by scanning electron microscopy images, X-ray diffraction analysis, elemental distribution, and binding energy. Moreover, the amount adsorbed of phosphate ion onto uncalcined and calcined NAZ was measured. That of phosphate ions onto the uncalcined was the largest of all. These results suggested that the adsorption of phosphate ions tends to depend on the physicochemical properties (e.g., amount of hydroxyl groups, pore volumes, and pH) of the adsorbents. Moreover, the adsorption mechanism of phosphate ions was evaluated on the basis of binding energy and elemental analysis. After adsorption, the binding energy of phosphorus P (2s and 2p) peaked and the sulfur peak intensity S(2s) reduced. This result indicated that the adsorption mechanism of phosphate would be exchanged with sulfate ions.


Assuntos
Alumínio/química , Complexos de Coordenação/química , Hidróxidos/química , Níquel/química , Fosfatos/química , Zircônio/química , Adsorção , Complexos de Coordenação/síntese química , Tamanho da Partícula , Propriedades de Superfície
16.
Talanta ; 212: 120795, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32113557

RESUMO

In the present study, a kind of Eu(III) post-functionalized Zr(IV)-based metal-organic framework (UiO-66(COOH)2, Zr-MOF: Eu3+) was synthesized and utilized as an independently luminescent probe for sensing bilirubin (BR) in human serum, a biomarker of jaundice hepatitis. It can be served as a turn-off fluorescent switch for BR because its red emission from Eu3+ can be easily quenched by BR through a fluorescent resonant energy transfer (FRET) process between BR and its ligands, and as a result, BR is recognized successfully. Particularly, Zr-MOF: Eu3+ has shown many appealing properties, such as high sensitivity, quick response (less than 1 min), broad response window (0-15 µM), and excellent selectivity. Most importantly, a kind of portable test paper based on Zr-MOF: Eu3+ probe has been developed for directly assessing the level of BR in real human serum and further diagnosing bilirubin-related diseases via visually observing the luminescent color variation.


Assuntos
Bilirrubina/sangue , Corantes Fluorescentes/química , Estruturas Metalorgânicas/química , Colorimetria/instrumentação , Colorimetria/métodos , Európio/química , Transferência Ressonante de Energia de Fluorescência , Humanos , Zircônio/química
17.
Chem Commun (Camb) ; 56(27): 3919-3922, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32149283
18.
Mikrochim Acta ; 187(4): 219, 2020 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-32166466

RESUMO

An impedimetric bioassay was constructed based on a nanohybrid of zirconium oxide nanoparticles and graphene-like nanofiber (denoted by ZrO2@GNF) for the determination of osteopontin (OPN). A series of ZrO2@GNF nanohybrids with different morphologies and nanostructures were derived from zirconium-based metal-organic frameworks (UiO-66) entrapped within the electric spun polyacrylonitrile (PAN) fiber (represented by UiO-66@PAN) by calcination at different temperatures. The basic characterizations revealed that the UiO-66@PAN nanofibers were collapsed into short nanorods. As such, homogeneously distributed ZrO2 nanoparticles were found to be embedded within the GNF nanostructure. This transition in the chemical structure and nanostructure not only can greatly enhance the electrochemical conductivity of the nanohybrid but also can strengthen the adsorbed bioaffinity toward OPN aptamer strands. As compared with bioassays based on ZrO2@GNF calcined at 500 °C and 900 °C, the ZrO2@GNF nanohybrid obtained at 700 °C (ZrO2@GNF700) demonstrated superior sensing performance, showing a determination limit of 4.76 fg mL-1 within a OPN concentration ranging 0.01 pg mL-1 to 2.0 ng mL-1. It also displayed high selectivity, accompanied by  good reproducibility and stability, acceptable applicability, and excellent repeatability. Graphical abstractSchematic representation of an impedimetric aptasensor based on nanohybrids of zirconium oxide nanoparticles and graphene-like nanofiber (ZrO2@CNF) was constructed for osteopontin detection. The ZrO2@CNF700 nanohybrid-based aptasensor demonstrated superior sensing performances, providing a promising tool for detecting cancer markers in biomedical diagnosis.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais , Técnicas Eletroquímicas , Grafite/química , Nanofibras/química , Osteopontina/análise , Zircônio/química
19.
BMC Oral Health ; 20(1): 80, 2020 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-32188431

RESUMO

BACKGROUND: Artificial intelligence (AI) is a branch of computer science concerned with building smart software or machines capable of performing tasks that typically require human intelligence. We present a protocol for the use of AI to fabricate implant-supported monolithic zirconia crowns (MZCs) cemented on customized hybrid abutments. METHODS: The study protocol consisted of: (1) intraoral scan of the implant position; (2) design of the individual abutment and temporary crown using computer-aided design (CAD) software; (3) milling of the zirconia abutment and the temporary polymethyl-methacrylate (PMMA) crown, with extraoral cementation of the zirconia abutment on the relative titanium bonding base, to generate an individual hybrid abutment; (4) clinical application of the hybrid abutment and the temporary PMMA crown; (5) intraoral scan of the hybrid abutment; (6) CAD of the final crown with automated margin line design using AI; (7) milling, sintering and characterisation of the final MZC; and (8) clinical application of the MZC. The outcome variables were mathematical (quality of the fabrication of the individual zirconia abutment) and clinical, such as (1) quality of the marginal adaptation, (2) of interproximal contact points and (3) of occlusal contacts, (4) chromatic integration, (5) survival and (6) success of MZCs. A careful statistical analysis was performed. RESULTS: 90 patients (35 males, 55 females; mean age 53.3 ± 13.7 years) restored with 106 implant-supported MZCs were included in the study. The follow-up varied from 6 months to 3 years. The quality of the fabrication of individual hybrid abutments revealed a mean deviation of 44 µm (± 6.3) between the original CAD design of the zirconia abutment, and the mesh of the zirconia abutment captured intraorally at the end of the provisionalization. At the delivery of the MZCs, the marginal adaptation, quality of interproximal and occlusal contacts, and aesthetic integration were excellent. The three-year cumulative survival and success of the MZCs were 99.0% and 91.3%, respectively. CONCLUSIONS: AI seems to represent a reliable tool for the restoration of single implants with MZCs cemented on customised hybrid abutments via a full digital workflow. Further studies are needed to confirm these positive results.


Assuntos
Inteligência Artificial , Desenho Assistido por Computador , Projeto do Implante Dentário-Pivô/métodos , Prótese Dentária Fixada por Implante , Prostodontia/métodos , Titânio/química , Zircônio/química , Adulto , Idoso , Coroas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
20.
Int J Nanomedicine ; 15: 1595-1610, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32210554

RESUMO

Introduction: The development of the field of biomaterials engineering is rapid. Various bioactive coatings are created to improve the biocompatibility of substrates used for bone regeneration, which includes formulation of thin zirconia coatings with pro-osteogenic properties. The aim of this study was to assess the biological properties of ZrO2 thin films grown by Atomic Layer Deposition (ALD) technology (ZrO2 ALD). Methodology: The cytocompatibility of the obtained layers was analysed using the mice pre-osteoblastic cell line (MC3T3) characterized by decreased expression of microRNA 21-5p (miR-21-5p) in order to evaluate the potential pro-osteogenic properties of the coatings. The in vitro experiments were designed to determine the effect of ZrO2 ALD coatings on cell morphology (confocal microscope), proliferative activity (cell cycle analysis) and metabolism, reflected by mitochondrial membrane potential (cytometric-based measurement). Additionally, the influence of layers on the expression of genes associated with cell survival and osteogenesis was studied using RT-qPCR. The following genes were investigated: B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), p53 and p21, as well as osteogenic markers, i.e. collagen type 1 (Coll-1), osteopontin (Opn), osteocalcin (Ocl) and runt-related transcription factor 2 (Runx-2). The levels of microRNA (miRNA/miR) involved in the regulation of osteogenic genes were determined, including miR-7, miR-21, miR-124 and miR-223. Results: The analysis revealed that the obtained coatings are cytocompatible and may increase the metabolism of pre-osteoblast, which was correlated with increased mitochondrial membrane potential and extensive development of the mitochondrial network. The obtained coatings affected the viability and proliferative status of cells, reducing the population of actively dividing cells. However, in cultures propagated on ZrO2 ALD coatings, the up-regulation of genes essential for bone metabolism was noted. Discussion: The data obtained indicate that ZrO2 coatings created using the ALD method may have pro-osteogenic properties and may improve the metabolism of bone precursor cells. Given the above, further development of ZrO2 ALD layers is essential in terms of their potential clinical application in bone regenerative medicine.


Assuntos
Materiais Biocompatíveis/química , Osteoblastos/citologia , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Zircônio/farmacologia , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Regulação da Expressão Gênica , Teste de Materiais , Camundongos , MicroRNAs/genética , Nanotecnologia/métodos , Osteoblastos/efeitos dos fármacos , Osteoblastos/ultraestrutura , Regulação para Cima , Zircônio/química
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