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1.
Molecules ; 25(1)2019 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-31881734

RESUMO

Para-, or 4-nitrophenol, and related nitroaromatics are broadly used compounds in industrial processes and as a result are among the most common anthropogenic pollutants in aqueous industrial effluent; this requires development of practical remediation strategies. Their catalytic reduction to the less toxic and synthetically desirable aminophenols is one strategy. However, to date, the majority of work focuses on catalysts based on precisely tailored, and often noble metal-based nanoparticles. The cost of such systems hampers practical, larger scale application. We report a facile route to bulk cobalt oxide-based materials, via a combined mechanochemical and calcination approach. Vibratory ball milling of CoCl2(H2O)6 with KOH, and subsequent calcination afforded three cobalt oxide-based materials with different combinations of CoO(OH), Co(OH)2, and Co3O4 with different crystallite domains/sizes and surface areas; Co@100, Co@350 and Co@600 (Co@###; # = calcination temp). All three prove active for the catalytic reduction of 4-nitrophenol and related aminonitrophenols. In the case of 4-nitrophenol, Co@350 proved to be the most active catalyst, therein its retention of activity over prolonged exposure to air, moisture, and reducing environments, and applicability in flow processes is demonstrated.


Assuntos
Cobalto/química , Nitrofenóis/química , Óxidos/química , Aminofenóis/química , Catálise , Oxirredução , Óxidos/síntese química , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Difração de Raios X
2.
Eur J Med Chem ; 178: 287-296, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31195170

RESUMO

Structure-activity relationships for rigid analogues of combretastatin A-4 (CA-4) were investigated, leading to the discovery of a series of 3,4-diaryl-1,2,5-oxadiazole-N-oxides. Among them, 7n' and 7n'' showed remarkable antiproliferative activities against three cancer cell lines in nanomolar concentrations. Interestingly, 7n' inhibited tubulin polymerization much more efficiently than CA-4. Cellular mechanism investigation elucidated 7n' disrupted the cellular microtubule structure, arrested cell cycle at G2/M phase and induces apoptosis. Molecular modeling study revealed 1,2,5-oxadiazole-N-oxide ring could increase a hydrogen bond interaction with the binding site. These results provide impetus and further guidance for the development of new CA-4 analogues.


Assuntos
Antineoplásicos/farmacologia , Desenho de Fármacos , Oxidiazóis/farmacologia , Óxidos/farmacologia , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Estrutura Molecular , Oxidiazóis/síntese química , Oxidiazóis/química , Óxidos/síntese química , Óxidos/química , Polimerização/efeitos dos fármacos , Relação Estrutura-Atividade
3.
Artif Cells Nanomed Biotechnol ; 47(1): 2230-2239, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31161806

RESUMO

Bacterial brown stripe (BBS) is one of the most economically important diseases of rice caused by Acidovorax oryzae (Ao). In order to ensure food security and safe consumption, the use of non-chemical approach is necessary. In this study, MgO and MnO2 were synthesized using chamomile flower extract. The synthesized MgO and MnO2 nanoparticles were characterized by UV-Visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission/scanning electron microscopy. The sizes were 18.2 and 16.5 nm for MgO and MnO2 nanoparticles, respectively. The MgO and MnO2 nanoparticles reduced the growth of Ao strain RS-2 by 62.9 and 71.3%, respectively. Also, the biofilm formation and swimming motility were significantly reduced compared to the control. The antibacterial mechanisms of MgO and MnO2 nanoparticles against RS-2 reveals that MgO and MnO2 nanoparticles penetrated the cells and destroyed the cell membrane leading to leakage of cytoplasmic content. Also, the flow cytometry observation reveals that the apoptotic cell ratio of RS-2 increased from 0.97% to 99.52 and 99.94% when treated with MgO and MnO2 nanoparticles, respectively. Altogether, the results suggest that the synthesized MgO and MnO2 nanoparticles could serve as an alternative approach method for the management of BBS.


Assuntos
Comamonadaceae/efeitos dos fármacos , Óxido de Magnésio/síntese química , Óxido de Magnésio/farmacologia , Compostos de Manganês/síntese química , Compostos de Manganês/farmacologia , Matricaria/química , Nanopartículas/química , Óxidos/síntese química , Óxidos/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Química Verde , Óxido de Magnésio/química , Compostos de Manganês/química , Testes de Sensibilidade Microbiana , Nanotecnologia , Óxidos/química , Extratos Vegetais/química
4.
Talanta ; 202: 591-599, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171226

RESUMO

Photodynamic therapy (PDT) was considered as an effective treatment. Whereas only PDT is not enough to achieve effective therapy on account of irradiation intensity decreases as depth increases as well as tumor hypoxia. Combination with gene therapy and photodynamic therapy have emerged as an effective strategy to improve therapeutic effectiveness. In the present study, a GSH responsive MnO2 was employed to delivery TB and DNAzyme for cancer imaging and PDT-gene combination treatment. TB, a photosensiters with aggregation-induced emission characteristic, was employed for photodynamic therapy, while DNAzyme, acting as catalysts for the degradation of EGR-1 mRNA, was exploited for gene silencing. All of the results of tumor treatment in vitro have implied that MnO2-DNAzyme-TB nanocomposite (MDT) can internalize into cells. Subsequently, MDT could decrease the expression of EGR-1 by gene silencing that enabling inhibition of cell growth. In addition, the singlet oxygen which was generated by the aggregated TB were able to further suppress cell growth. Combination therapy of photodynamic as well as gene therapy greatly enhanced antitumor efficiencies. Furthermore, in vivo tumor treatment experiments demonstrated that MDT under illumination can effectively inhibit the tumor growth of MCF-7 tumor-bearing mice by photodynamic and gene silencing combination therapy.


Assuntos
Antineoplásicos/farmacologia , DNA Catalítico/metabolismo , Terapia Genética , Compostos de Manganês/farmacologia , Óxidos/farmacologia , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , DNA Catalítico/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Proteína 1 de Resposta de Crescimento Precoce/antagonistas & inibidores , Proteína 1 de Resposta de Crescimento Precoce/genética , Feminino , Humanos , Células MCF-7 , Neoplasias Mamárias Experimentais/diagnóstico por imagem , Neoplasias Mamárias Experimentais/tratamento farmacológico , Neoplasias Mamárias Experimentais/metabolismo , Compostos de Manganês/síntese química , Compostos de Manganês/química , Camundongos , Camundongos Nus , Nanocompostos , Imagem Óptica , Óxidos/síntese química , Óxidos/química , Tamanho da Partícula , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/genética , Relação Estrutura-Atividade , Propriedades de Superfície
5.
Mikrochim Acta ; 186(6): 354, 2019 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-31098776

RESUMO

The authors present a colorimetric method for the evaluation of the hydroxyl radical scavenging capability of antioxidants by exploiting carbon-confined mixed cobalt oxide nanoparticles (denoted as C-confined CoOx NPs) as a novel peroxidase mimic. The nanozyme can be prepared from the metal-organic framework ZIF-67 by calcination at a moderate temperature. It exhibits peroxidase-mimicking activity and catalyzes the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to form a blue product in the presence of H2O2 via generation of hydroxyl radicals. However, in the presence of an antioxidant, the color reaction is suppressed due to scavenging of hydroxyl radicals by the antioxidant. Based on this principle, the hydroxy radical scavenging ability of glutathione (GSH), cysteine (Cys), tannic acid (TA) and tea polyphenols (TP) was assessed. It was found that these antioxidants can scavenge hydroxyl radicals in the following decreasing order: TA>Cys>GSH>TP. The assay was also used to quantify the antioxidative power of common fruit extracts. Graphical abstract Schematic presentation for evaluating the hydroxyl radical scavenging ability of different antioxidants using carbon-confined mixed cobalt oxide nanoparticles (denoted as C-confined CoOx NPs) as a highly active peroxidase mimic. With excellent activity, the C-confined CoOx NPs together with the visible peroxidase reaction can be employed as a powerful tool to rapidly screen appropriate antioxidants from natural samples and measure their activity for guiding their usage in related products.


Assuntos
Antioxidantes/metabolismo , Carbono/metabolismo , Cobalto/metabolismo , Colorimetria , Radical Hidroxila/metabolismo , Óxidos/metabolismo , Peroxidases/metabolismo , Carbono/química , Cobalto/química , Radical Hidroxila/análise , Nanopartículas/química , Óxidos/síntese química , Óxidos/química , Tamanho da Partícula , Peroxidases/química , Propriedades de Superfície
6.
Molecules ; 24(7)2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30935001

RESUMO

A simple and efficient protocol for the oxidation of trifluoromethyl, mono- and difluoromethyl sulfides to the corresponding sulfoxides without over-oxidation to sulfones, using TFPAA prepared in situ from trifluoroacetic acid and 15% H2O2 aqueous solution was developed. The methodology is suitable for a wide range of aromatic and aliphatic substrates in milligram and multigram scales.


Assuntos
Compostos de Flúor/síntese química , Óxidos/síntese química , Sulfetos/química , Catálise , Peróxido de Hidrogênio/química , Oxirredução , Sulfonas/química , Sulfóxidos/química , Água/química
7.
Chemosphere ; 227: 505-513, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31004817

RESUMO

The existence of Cr(VI) and antibiotics in the environment can form the joint contaminant which can be hazardous to the ecosystem. To deal with this, we have explored a plausible method to remove the Cr(VI) and tetracycline (TC) from water by visible light photocatalysis. In this study, a series of reduced graphene oxide@ZnAlTi layered double oxides (rGO@LDO) composites with different doping ratio of rGO were successfully synthesized, which were applied in photocatalytic reduction of Cr(VI) and oxidation of TC. Graphene acts as an electron donor and it can enhance the adsorption of Cr(VI) and TC on the surface of the composites. It's found that the obtained ZnAlTi-LDO composites doped with rGO have higher photo-responsiveness in the visible region. The best-performing rGO@LDO composite (i.e., CGL3) exhibited enhanced visible light-driven photocatalytic Cr(VI) reduction, which was about five times higher than those of ZnAlTi-LDO (without adding hole catcher). The rGO@LDO also showed a satisfactory performance for photocatalytic oxidation of TC with the total organic carbon removal of 80%. However, the doping of rGO did not significantly enhance the removal of TC. The experiment of pH effects demonstrated that acidic pH was favorable to photocatalytic reduction of Cr(VI), while neutral pH was favorable to photocatalytic oxidation of TC. The band structure of ZnAlTi-LDO was first identified, and the EVB and ECB of ZnAlTi-LDO are -2.32 and 0.72 V (vs. RHE). This research provides a feasible method to remove Cr(VI) and tetracycline from water by employing ZnAlTi-LDO doped with rGO as photocatalyst.


Assuntos
Cromo/isolamento & purificação , Grafite/química , Luz , Óxidos/síntese química , Tetraciclina/isolamento & purificação , Adsorção , Catálise , Concentração de Íons de Hidrogênio , Oxirredução , Óxidos/química , Poluentes Químicos da Água/química , Compostos de Zinco/química
8.
Anal Chim Acta ; 1065: 21-28, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31005147

RESUMO

This report outlines an ultrasensitive electrochemiluminescence (ECL) sensing platform based on water-soluble tungsten oxide quantum dots (WOx QDs) for the detection of dopamine (DA) released from P12 cells. The WOx QDs with good stability and water solubility were prepared by a facile and green hydrothermal method, and used to modify a glassy carbon electrode (WOx QDs/GCE). The proposed ECL sensor exhibited a stable and strong cathodic ECL signal when potassium peroxodisulfate (K2S2O8) as the coreactant in aqueous solution. The possible ECL mechanism was studied and deduced, and the ECL response signal of the proposed sensor decreased rapidly in the presence of dopamine (DA). Under optimal conditions, the ECL signals of WOx QDs linearly decreased with the increase of DA concentration in the range of 10-15 M to 10-9 M and 10-9 M to 10-5 M, respectively. The detection limit was as low as 10-15 M (S/N = 3). Based on these results, this method has been successfully applied to the determination of DA released by PC12 cells. The detection linear range for the detection of DA released by PC12 cells was from 0.1 to 0.9 µM with a detection limit of 0.045 µM. Therefore, the proposed ECL sensor displayed high sensitivity, good specificity and long-term stability, which may shed light on a new way to construct other high-performance ECL detection systems based on WOx or WOx QDs-based nanocomposites.


Assuntos
Técnicas Biossensoriais , Dopamina/análise , Técnicas Eletroquímicas , Medições Luminescentes , Óxidos/química , Pontos Quânticos/química , Tungstênio/química , Animais , Dopamina/metabolismo , Óxidos/síntese química , Células PC12 , Tamanho da Partícula , Ratos , Solubilidade , Propriedades de Superfície , Água/química
9.
Sci Total Environ ; 670: 1159-1169, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31018432

RESUMO

In this study, amorphous Mn oxides (AMOs) and their composites with biochar (BC) were synthesized using different sugars (glucose, sucrose, and molasses), and their sorption efficiency toward Zn(II), Cd(II), and As(V) was tested. Additionally, detailed characterization of synthesized materials using various solid-state analysis methods (e.g. XRD, FTIR-ATR, and/or SEM-EDX) was also performed. Despite glucose-based AMOs presented higher sorption efficiency for As(V), i.e., 0.73 mmol g-1 (glucose) > 0.27 mmol g-1 (sucrose and molasses), similar sorption efficiency toward Zn(II), i.e., 0.80 mmol g-1 (glucose and molasses) > 0.66 (sucrose) and Cd(II) (0.71-0.74 mmol g-1 (sucrose and molasses) > 0.36 mmol g-1 (glucose), was observed for sucrose- and molasses-based AMOs under the given conditions. Next, the sorption efficiency of all AMO/BC composites was proportional to their AMO content. Finally, Mn(II) leaching from the structure of the new AMOs was negligible compared to that observed for the glucose-based AMOs, in this study as well as in other similar studies. Moreover, using molasses as reducing agent during AMO synthesis dramatically decreased the total cost of the final materials, which suggested that these new AMOs could represent interesting alternatives for standard remediation technologies. The AMOs synthesized using low-cost sugars could, therefore, be promising materials for real field applications, since the main disadvantages of using standard AMOs are mitigated. Nevertheless, the efficiency and stability of these composites under real-life conditions must be tested prior to their direct application for remediation technologies.


Assuntos
Carvão Vegetal/química , Compostos de Manganês/síntese química , Óxidos/síntese química , Açúcares/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Arsênico/análise , Cádmio/análise , Zinco/análise
10.
PLoS One ; 14(3): e0213151, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30883551

RESUMO

We previously synthetized molybdenum oxide (MoO3) nanoparticles (NP) and showed their antibacterial activity against a representative collection of the most relevant bacterial species responsible for hospital-acquired infections, including Staphylococcus aureus. The aim of the present study was to prepare and characterize a novel coating with these MoO3 NP, confirm its mechanical stability, and investigate its biocidal effect to reduce S. aureus contamination on inanimate surfaces. In addition, the novel MoO3 NP coating was compared to a silver (Ag) NP coating synthetized by the same procedure. The MoO3 and Ag NP coatings were characterized in terms of their chemical structure by FT-IR, surface morphology by scanning electron microscopy, and mechanical properties by tensile and adhesion tests. The antimicrobial activity of the coatings was tested by following the loss of viability of S. aureus after 6h, 24h, 48h, and 72h exposure. MoO3 and Ag coatings exhibited surfaces of comparable morphologies and both presented elastomeric properties (tensile strength of ~420 kPa, Young's modulus of ~48 kPa, and maximum elongation of ~12%), and excellent (classification of 5B) adhesion to glass, steel and polystyrene surfaces. The two coatings exhibited a good antibacterial activity (R) against S. aureus over time (RMoO3 = 0.2-0.81; RAg = 0.61-2.37), although the effect of the Ag NP coating was more pronounced, especially at 72h (RMoO3 = 0.81 vs RAg = 2.37). Noteworthy, contrary to the Ag NP coating, the MoO3 NP coating was colourless and transparent, avoiding undesired unaesthetic effects. The synthetized coating with NP of MoO3, which has low toxicity to humans, capability of biodegradation, and rapid excretion, can be applied onto most standard materials and therefore is a promising tool to reduce S. aureus contamination on usual inanimate surfaces found in healthcare and community environments.


Assuntos
Antibacterianos/farmacologia , Contaminação de Equipamentos/prevenção & controle , Óxidos/síntese química , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Materiais Revestidos Biocompatíveis/síntese química , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Nanopartículas Metálicas/química , Molibdênio/química , Molibdênio/farmacologia , Óxidos/química , Óxidos/farmacologia , Prata/química , Prata/farmacologia , Propriedades de Superfície
11.
Ecotoxicol Environ Saf ; 168: 35-44, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30384165

RESUMO

The LaFeO3 perovskite oxide decorated active carbon fibers (LFO-ACFs) based on cotton fabric waste were successfully synthesized through sol-gel loading and thermal treatment. LaFeO3 perovskite and cotton fabric waste were combined to an eco-friendly and cheap adsorbent, which could reuse the leftover materials of textile industry and realize their functional modification. The structural, morphology/microstructure and functional groups were investigated through X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), Fourier Transform Infrared spectroscopy (FTIR), respectively. The XRD pattern suggested the cotton fabric matrix didn't influence the structure of LaFeO3 perovskite oxide. In SEM studies, LFO-ACFs still maintained fibrous shape of the raw cotton fibers, and the EDX analysis showed that the main elements of the prepared LFO-ACFs were La, Fe, O and C. The synthesized LFO-ACF was employed for adsorption of cational dye of Rhodamine B (RhB), and the effects of adsorption parameters, i.e. pH, contact time, solution temperature and initial concentration of dye, on adsorption behavior were investigated. Results suggested the adsorption performance of LFO-ACF for RhB was nearly not affected by solution pH and its maximum adsorption capacity fitted by the Langmuir isothermal model could attain 182.6 mg/g at 293 K. The adsorption kinetics followed the pseudo-second-order equation and the regeneration of LFO-ACF could be well realized through an easy pyrolysis method.


Assuntos
Compostos de Cálcio/síntese química , Óxidos/síntese química , Rodaminas/química , Adsorção , Carvão Vegetal/química , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Indústria Têxtil , Titânio , Eliminação de Resíduos Líquidos , Águas Residuárias/química , Poluentes Químicos da Água/química , Difração de Raios X
12.
J Environ Manage ; 230: 199-211, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30286349

RESUMO

Here in, we presented a facile one-step method for the synthesis of Graphene oxide-silver (GO-Ag) nanocomposite and its applications as a sorbent for the elimination of some toxic pollutants from aqueous medium, as an efficient catalyst in the individual as well as simultaneous reduction reactions of multiple compounds, and as an antibacterial agent for the destruction of some harmful microorganisms existent in wastewater. GO was prepared using a modified Hummers method and Ag nanoparticles were integrated on GO sheets by chemical reduction of Ag+ ions on the surfaces of GO sheets. The composition and morphology of the nanocomposite was extensively characterized with elemental dispersive X-ray analysis (EDX), Fourier transform infra-red (FT-IR) spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The GO-Ag nanocomposite demonstrated remarkable adsorption capacities and recyclability for malachite green (MG) and ethyl violet (EV) dyes. Various experimental parameters affecting adsorptive behavior of nanocomposite like temperature, pH, time of contact between dye and adsorbent, and adsorbent dose were evaluated thoroughly. Experimental data was simulated with different adsorption isotherms and kinetic models to evaluate adsorption behavior of both dyes and results confirmed the adsorption of both the dyes to be followed by pseudo 2nd order kinetic model and Langmuir adsorption model. Moreover, adsorbent was regenerated in suitable media for both dyes without any loss in removal efficiency. The catalytic performance for the 2-nitroaniline (2-NA) reduction was investigated in detail. Most importantly, the prepared nanocomposite was found to have potential to adsorb multiple pollutants all together as well as to catalyze the simultaneous reduction of a mixture of dyes (MG, MO, and EV) and 2-NA. An additional advantage of the GO-Ag nanocomposite was its antibacterial activity acquired to the presence of Ag nanoparticles. Two bacterial strains (Gram-negative bacterium, E. coli and the Gram-positive bacterium, S. aureus) were used to test antibacterial activity of composite and the results confirmed the remarkable performance of the nanocomposite in destroying harmful pathogens.


Assuntos
Antibacterianos/química , Grafite/química , Nanopartículas Metálicas/química , Óxidos/química , Compostos de Prata/química , Água/química , Adsorção , Antibacterianos/farmacologia , Catálise , Descontaminação , Escherichia coli/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Óxidos/síntese química , Compostos de Prata/síntese química , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos
13.
J Photochem Photobiol B ; 190: 154-162, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30572187

RESUMO

The present study explored the one step extracellular green synthesis of Iron oxide (FexOy) and manganese oxide nanoparticles (MnNPs) using aqueous extract of Acorus calamus rhizome. The organic chemicals including polyphenol compounds responsible for bio-reduction and stabilization from the polyphenol enriched microwave irradiated aqueous extract of Acorus calamus were studied using GC-MS analysis. Further, their synthesis conditions were optimized using response surface methodology (RSM) and central composite design (CCD) using three variables. The green synthesized Iron oxide and Manganese oxide NPs were characterized by UV, FTIR, XRD, TEM and SEM. Results indicated that the Iron oxide NPs and mixture of iron and manganese NPs showed photocatalytic excellent activities in reducing dyes like methylene blue (0.1%) and Congo red (0.25%) at 0.03% NPs. However, Mn NPs showed moderate activity. On a contrary, manganese showed better larvicidal activity compared to Iron oxide NPs against the phytopathogens commonly affecting the vegetable crops. The present finding showed that high mortality rate at 30 µg/ml concentration of manganese NPs was comparatively interesting. In addition, NPs overall had appreciable activity with P. aeruginosa being more sensitive to Iron oxide NPs (22 ±â€¯2 mm zone of inhibition) and manganese NPs (13 ±â€¯2 mm zone of inhibition) and Iron oxide NPs completely inhibited the growth of A. flavus at 40 µg/ml concentration.


Assuntos
Acoraceae/química , Antibacterianos/síntese química , Compostos Azo/química , Química Verde/métodos , Inseticidas/síntese química , Aspergillus flavus/efeitos dos fármacos , Compostos Férricos/síntese química , Compostos de Manganês/síntese química , Nanopartículas/química , Nanopartículas/uso terapêutico , Óxidos/síntese química , Extratos Vegetais/química , Polifenóis/análise , Pseudomonas aeruginosa/efeitos dos fármacos
14.
Anal Chim Acta ; 1047: 267-274, 2019 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-30567659

RESUMO

89Sr and 90Sr are both fission products of high radiotoxicity, which can be released in significant amounts in the event of a nuclear accident. Radiostrontium isotopes will follow calcium all along the food chain and, after ingestion, accumulate in the bones. Therefore, it is imperative to be able to determine 89Sr and 90Sr in raw milk samples in case of an accidental situation to evaluate the dose given by both radionuclides to the population. Several methods exist for conducting 89Sr and 90Sr determination. However, most of them use at least one chromatographic step to purify strontium. This, unfortunately, increases the analytical time before the results can be released to the authorities. In addition, they often use liquid scintillation counting to determine the 89Sr and 90Sr activities, a method which can handle only one sample at a time. Here we propose using synthetic tunnel manganese oxides such as cryptomelane and todorokite and layered metal sulfides to selectively extract strontium from fresh milk and raw urine in a batch sorption method. We found that the method is very quick and yields very pure sources of (radio)-strontium, which can be counted in a proportional counter. Data (counts per minute) from the counter were fitted to a mathematical expression enabling the simultaneous determination of 89Sr and 90Sr. Because a proportional counter often has several drawers, it is typically possible to measure up to 16 samples at a time. Since cryptomelane is a binding phase easily synthesized in a large quantity, we anticipate that this technique could be an interesting alternative to conventional solid phase extraction chromatography methods.


Assuntos
Contaminação de Alimentos/análise , Compostos de Manganês/química , Leite/química , Óxidos/química , Radioisótopos de Estrôncio/urina , Sulfetos/química , Animais , Humanos , Compostos de Manganês/síntese química , Óxidos/síntese química , Sulfetos/síntese química
15.
Ultrason Sonochem ; 53: 44-54, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30559078

RESUMO

In this work, strontium cerate nanoparticles (SrCeO3 NPs, SC NPs) were developed through facile synthetic techniques (Ultrasound-Assisted (UA) and Stirring-Assisted (SA) synthesis) and utilized as an electrocatalyst for the selective and sensitive electrochemical detection of calcium channel blocker nifedipine (NDF). The as-prepared UASC NPs and SASC NPs were characterized using XRD, Raman, TEM, EDS, mapping, XPS and BET analysis which exposed the formation of SC NPs in the form of spherical in shape and well crystalline in nature. BET studies reveal that UASC NPs have maximum surface area than that of SASC NPs. Further, the use of the as-developed UASC NPs and SASC NPs as an electrocatalyst for the detection of NDF. Interestingly, the UASC NPs modified screen printed carbon electrode (UASC NPs/SPCE) exhibited an excellent electrocatalytic activity in terms of lower reduction potential and enhanced reduction peak current when compared to SASC NPs and unmodified SPCE. Moreover, as-prepared UASC NPs/SPCE displayed wide linear response range (LR, 0.02-174 µM), lower detection limit (LOD, 5 nM) and good sensitivity (1.31 µA µM-1 cm-2) than that of SASC NPs (LR = 0.02-157 µM, LOD = 6.4 nM, sensitivity - 1.27 µA µM-1cm-2). Furthermore, UASC NPs/SPCE showed an excellent selectivity even in the existence of potentially co-interfering compounds such as similar functional group containing drugs, pollutants, biological substances and some common cations/anions. The developed sensor was successfully employed for the determination of NDF in real lake water, commercial NDF tablet and urine samples with acceptable recovery.


Assuntos
Bloqueadores dos Canais de Cálcio/análise , Limite de Detecção , Nanopartículas/química , Nifedipino/análise , Óxidos/química , Óxidos/síntese química , Sonicação , Bloqueadores dos Canais de Cálcio/química , Catálise , Técnicas de Química Sintética , Eletroquímica , Eletrodos , Nifedipino/química
16.
Eur J Med Chem ; 163: 736-746, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30576904

RESUMO

This work reports an efficient diastereoselective synthetic methodology for the preparation of phosphorus substituted cyanoaziridines through the nucleophilic addition of TMSCN, as cyanide source, to the C-N double bond of 2H-azirine derivatives. The aziridine ring, in these novel cyanoaziridines, can be activated by simple N-tosylation or N-acylation. In addition, the cytotoxic effect on cell lines derived from human lung adenocarcinoma (A549) and human embryonic kidney (HEK293) was also screened. N-H and N-Substituted cyanoaziridines showed excellent activity against the A549 cell line in vitro. Moreover, selectivity towards cancer cell (A549) over (HEK293), and non-malignant cells (MCR-5) has been observed.


Assuntos
Aziridinas/farmacologia , Organofosfonatos/farmacologia , Óxidos/farmacologia , Células A549 , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Aziridinas/síntese química , Proliferação de Células/efeitos dos fármacos , Cianetos , Células HEK293 , Humanos , Organofosfonatos/síntese química , Óxidos/síntese química , Relação Estrutura-Atividade
17.
ACS Appl Mater Interfaces ; 11(3): 3323-3333, 2019 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-30589536

RESUMO

Black titanium oxide has attracted tremendous interest in tumor phototherapy via converting light energy to heat and reactive oxygen species (ROS). Nevertheless, current synthesis methods suffer from inert gas shielding, high costs, complicated procedures, and expensive facilities, which are fairly impractical for treatment application. Herein, we propose a one-step strategy for fast facile synthesis of black TiO nanoparticles via a microwave-assisted hydrothermal synthesis approach with Ti power, hydrochloric acid, and hydrofluoric acid without the requirement of an reducing agent and high-temperature calcination. The prepared black TiO nanoparticles with an average size of 52 nm exhibit strong absorbance from ultraviolet (UV) to near-infrared light region, favoring a single agent and single light-induced synergistic phototherapy of tumors. The black TiO nanoparticles shows an excellent performance in phototherapy with a photothermal conversion efficiency up to 50% and a prominent ROS generation under 808 nm laser irradiation. The toxicity and therapeutic effect in vitro and in vivo are investigated, and the results elucidate that black TiO nanoparticles possess good biocompatibility and remarkable synergistic tumor therapeutic efficacy. The proposed microwave-assisted method opens up a novel way for the synthesis of titanium-based material in a simple and fast manner, promoting their applications in the biomedical field.


Assuntos
Nanopartículas Metálicas/administração & dosagem , Neoplasias/terapia , Fototerapia , Titânio/administração & dosagem , Animais , Linhagem Celular Tumoral , Doxorrubicina/administração & dosagem , Doxorrubicina/química , Sinergismo Farmacológico , Temperatura Alta/uso terapêutico , Humanos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/uso terapêutico , Camundongos , Micro-Ondas , Neoplasias/patologia , Óxidos/administração & dosagem , Óxidos/síntese química , Óxidos/química , Espécies Reativas de Oxigênio/química , Titânio/química , Ensaios Antitumorais Modelo de Xenoenxerto
18.
ACS Nano ; 12(12): 12682-12691, 2018 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-30507161

RESUMO

Integration of biological macromolecules with inorganic materials via biomineralization has demonstrated great potential for development of nanotheranostic agents. To produce multifunctionality, integration of multiple components in the biomineralized theranostic agents is required; however, how to efficiently and reproducibly implement this is challenging. In this report, a universal biomineralization strategy is developed by incorporation of oxidization polymerization into albumin-templated biomineralization for facile synthesis of nanotheranostic agents. A series of biomineralized polymers and manganese dioxide hybrid nanoparticles (PMHNs) can be synthesized via the polymerization of various monomers, including dopamine (DA), epigallocatechin (EGC), pyrrole (PY), and diaminopyridine (DP), along with the reduction of KMnO4 and formation of manganese dioxide nanoparticles in albumin templates. These biomineralized PMHNs demonstrate ultrahigh MRI (longitudinal relaxivity up to 38 mM-1 s-1) and ultrasonic (US) imaging contrasting capabilities and have excellent photothermal therapy efficacy with complete ablation of orthotopic tumors. Moreover, these biomineralized hybrid nanoparticles can be effectively excreted through the kidneys, avoiding potential systemic toxicity. Thus, integration of polymerization into biomineralization presents a strategy for the fabrication of hybrid nanomaterials, allowing the production of multifunctional and biocompatible nanotheranostic agents via a facile one-pot method.


Assuntos
Antineoplásicos/farmacologia , Compostos de Manganês/farmacologia , Nanopartículas/química , Óxidos/farmacologia , Polímeros/farmacologia , Nanomedicina Teranóstica , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Biomineralização , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Imagem por Ressonância Magnética , Compostos de Manganês/síntese química , Compostos de Manganês/química , Camundongos , Células NIH 3T3 , Óxidos/síntese química , Óxidos/química , Fototerapia , Polimerização , Polímeros/síntese química , Polímeros/química
19.
J Vis Exp ; (140)2018 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-30417876

RESUMO

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. Here, we introduce the molten-salt synthesis (MSS) method for making metal oxide nanomaterials. Advantages over other methods include its simplicity, greenness, reliability, scalability, and generalizability. Using pyrochlore lanthanum hafnium oxide (La2Hf2O7) as a representative, we describe the MSS protocol for the successful synthesis of complex metal oxide nanoparticles (NPs). Furthermore, this method has the unique ability to produce NPs with different material features by changing various synthesis parameters such as pH, temperature, duration, and post-annealing. By fine-tuning these parameters, we are able to synthesize highly uniform, non-agglomerated, and highly crystalline NPs. As a specific example, we vary the particle size of the La2Hf2O7 NPs by changing the concentration of the ammonium hydroxide solution used in the MSS process, which allows us to further explore the effect of particle size on various properties. It is expected that the MSS method will become a more popular synthesis method for nanomaterials and more widely employed in the nanoscience and nanotechnology community in the upcoming years.


Assuntos
Háfnio/química , Óxidos/química , Óxidos/síntese química , Sais/química , Técnicas de Química Sintética , Nanopartículas , Nanotecnologia , Tamanho da Partícula , Reprodutibilidade dos Testes
20.
Molecules ; 23(9)2018 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-30205570

RESUMO

Nano Molybdenum trioxide (α-MoO3) was synthesized in an easy and efficient approach. The removal of methylene blue (MB) in aqueous solutions was studied using this material. The effects of various experimental parameters, for example contact time, pH, temperature and initial MB concentration on removal capacity were explored. The removal of MB was significantly affected by pH and temperature and higher values resulted in increase of removal capacity of MB. The removal efficiency of Methylene blue was 100% at pH = 11 for initial dye concentrations lower than 150 ppm, with a maximum removal capacity of 152 mg/g of MB as gathered from Langmuir model. By comparing the kinetic models (pseudo first-order, pseudo second-order and intraparticle diffusion model) at various conditions, it has been found that the pseudo second-order kinetic model correlates with the experimental data well. The thermodynamic study indicated that the removal was endothermic, spontaneous and favorable. The thermal regeneration studies indicated that the removal efficiency (99%) was maintained after four cycles of use. Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM) confirmed the presence of the MB dye on the α-MoO3 nanoparticles after adsorption and regeneration. The α-MoO3 nanosorbent showed excellent removal efficiency before and after regeneration, suggesting that it can be used as a promising adsorbent for removing Methylene blue dye from wastewater.


Assuntos
Azul de Metileno/química , Óxidos/síntese química , Soluções/química , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Molibdênio/química , Nanoestruturas , Óxidos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
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