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1.
World J Microbiol Biotechnol ; 36(2): 25, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31980951

RESUMO

In a search for novel therapeutic agents against pathogenic fungal species, Candida in addition to bacterial species, novel spinel nanoferrites were assayed against four pathogenic fungi isolated from different clinical samples of ear and skin infections: Aspergillus flavus, A. niger, A. terrus and A. fumigatus, four Candia species: Candida albicans, C. parapsilosis, C. krusei and C. tropicales, and four bacterial species: two Gram +ve: Bacillus subtilis and Streptococcus pyogenes, and two Gram -ve: Pseudomonas vulgaris and Escherichia coli. It was found that the assayed compounds displayed different levels of antifungal and antibacterial activities against all tested microorganisms. The antimicrobial potency depends on the method of synthesis of the nanoparticles and also on the microbial species.


Assuntos
Antibacterianos/síntese química , Antifúngicos/síntese química , Compostos Férricos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Compostos Férricos/química , Compostos Férricos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nanopartículas , Relação Estrutura-Atividade
2.
Top Curr Chem (Cham) ; 378(1): 12, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31907672

RESUMO

Nanomaterials have revolutionized the sensing and biosensing fields, with the development of more sensitive and selective devices for multiple applications. Gold, silver and iron oxide nanoparticles have played a particularly major role in this development. In this review, we provide a general overview of the synthesis and characteristics of gold, silver and iron oxide nanoparticles, along with the main strategies for their surface functionalization with ligands and biomolecules. Finally, different architectures suitable for electrochemical applications are reviewed, as well as their main fabrication procedures. We conclude with some considerations from the authors' perspective regarding the promising use of these materials and the challenges to be faced in the near future.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Compostos Férricos/síntese química , Ouro/química , Nanopartículas/química , Prata/química , Compostos Férricos/química , Ligantes , Propriedades de Superfície
3.
Chemosphere ; 241: 125021, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683448

RESUMO

The magnetic composite CoFe2O4/ZIF-8 based on metal organic framework (MOF) with high specific surface area and high activity was synthesized by solvothermal method. The prepared catalysts were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), vibration sample magnetometer (VSM) and N2 adsorption-desorption isotherms, respectively. After characterization, CoFe2O4/ZIF-8 was applied to heterogeneous activation of peroxymonosulfate (PMS) for degrading methylene blue (MB). The result showed that the 0.075-CoFe2O4/ZIF-8 sample had the excellent catalytic activity. After catalytic reaction for 60 min, the degradation efficiency of MB (20 mg/L) reached about 97.9% at room temperature of 20 °C. The quenching experiment and electron paramagnetic resonance (EPR) analysis indicated that SO4- and OH radicals were the main active species in MB degradation. Meanwhile, the possible MB degradation mechanism was proposed. After four catalytic cycles, the degradation efficiency of MB has not been greatly reduced, indicating the practical application potential of CoFe2O4/ZIF-8 in water pollution cleanup.


Assuntos
Cobalto/química , Corantes/química , Compostos Férricos/química , Estruturas Metalorgânicas/química , Peróxidos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Catálise , Compostos Férricos/síntese química , Magnetismo , Azul de Metileno/química
4.
Mater Sci Eng C Mater Biol Appl ; 104: 109932, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499934

RESUMO

Nanomaterial based paints are in current demand in the area of surface protective coatings due to the significant advances made to improve their antibacterial and anticorrosion characteristics. In this work, we have developed magnetic graphene oxide (MGO) paint with the incorporation of cobalt ferrite (CF) and graphene oxide (GO) along with paint materials by using high energy ball milling (HEBM). Morphological, elemental and functional analysis of the MGO paint is studied with ESEM, AFM, Raman, FTIR spectroscopy. EDS and PIXE methods are used for elemental analysis. Thermal analysis shows that the MGO film was stable up to 100 °C. The saturation magnetization of CF MNP is observed as 76 emu/g and it is reduced to 12 emu/g for MGP paint. The detailed antibacterial study of the prepared MGO paint has performed with S. typhimurium and E. coli. The dead-live assessment shows the dead population for S. typhimurium is superior up to 82% whereas it is 20% for E. coli. The morphological damage of bacterial cells is studied using SEM technique. Flow cytometry analysis of reactive oxygen species (ROS) generation experiments and computational analysis supported the proposed mechanism of induced ROS for the damage of bacterial membrane via interaction of GO and CF with bacterial proteins leading to alteration in their functionality. The observed results indicate that the prepared MGO paint could be a better candidate in the area of nano paint for surface protective coatings.


Assuntos
Antibacterianos/farmacologia , Materiais Revestidos Biocompatíveis/síntese química , Compostos Férricos/síntese química , Grafite/síntese química , Nanopartículas de Magnetita/química , Via Secretória/efeitos dos fármacos , Antibacterianos/síntese química , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Materiais Revestidos Biocompatíveis/farmacologia , Cobalto/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Compostos Férricos/farmacologia , Grafite/farmacologia , Humanos , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Propriedades de Superfície , Temperatura , Termogravimetria , Vibração
5.
Mater Sci Eng C Mater Biol Appl ; 104: 109922, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499936

RESUMO

Synthesis of monodisperse carboxylic acid-functionalized magnetic mesoporous silica nanoparticles is performed by either two-step sol-gel process or post-grafting using citric acid modified isocyanate silane coupling agent (MMSN-NCO-CA) or succinic anhydride modified magnetic mesoporous silica (MMSN-NH-SA). Morphology, structure and magnetic properties of bare and mesoporous silica coated Fe3O4 core were studied using various techniques such as FTIR, VSM, TEM, FESEM, XRD and N2 adsorption-desorption isotherms (BET). Cisplatin (cis-Pt) adsorption isotherms and its release profile in various media were investigated by ICP-OES. MMSN-NCO-CA with mean particle size 107 nm had lower surface area (87.5 m2/g) and larger pore size (6.9 nm) in comparison with MMSN-NH-SA (respective values of 151.2 m2/g and 3.5 nm). cis-Pt loading into particles followed a saturable adsorption with respect to the drug to particle mass ratios. More sustained release of cis-Pt was observed for MMSN-NCO-CA, though both nanoparticles exhibited a pH- and saline concentration-dependent drug release. In addition, general and cis-Pt specific cytotoxicity were examined by MTT assay in MDA-MB-231 breast cancer cell line, and to further detect apoptosis, acridine orange/ethidium bromide dual cell staining was investigated by fluorescence microscopy. In-vitro anti-tumor efficiency of cis-Pt loaded MMSN-NCO-CA and MMSN-NH-SA were similarly enhanced in comparison to free cis-Pt; however, more specific apoptotic death occurred for cis-Pt loaded MMSN-NCO-CA. Therefore, the as-synthesized citric acid functionalized core-shell magnetic mesoporous hybrid nanoparticles could be used as a promising drug carriers for cancer therapy in-vivo.


Assuntos
Cisplatino/administração & dosagem , Ácido Cítrico/química , Sistemas de Liberação de Medicamentos , Compostos Férricos/química , Nanopartículas/química , Salinidade , Silanos/química , Dióxido de Silício/química , Adsorção , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ácido Cítrico/síntese química , Liberação Controlada de Fármacos , Compostos Férricos/síntese química , Hemólise , Humanos , Hidrodinâmica , Concentração de Íons de Hidrogênio , Cinética , Magnetometria , Nanopartículas/ultraestrutura , Porosidade , Silanos/síntese química , Dióxido de Silício/síntese química , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Propriedades de Superfície , Difração de Raios X
6.
Molecules ; 24(14)2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31319493

RESUMO

CuO/MgAl2O4 and CuO/MgFe2O4 catalysts were successfully synthesized with the use of spinel supports by a very simple and low-cost mechanochemical method. High-speed ball-milling was used to synthesize these catalyst supports for the first time. Materials were subsequently characterized by using XRD, FESEM, TEM, EDS-Dot mapping, XPS, BET-BJH, and Magnetic Susceptibility to investigate the physical-chemical characteristics of the catalysts. Acidity evaluation results indicated that the catalyst with the Mg-Al spinel support had more acid sites. XRD results showed a successful synthesis of the catalysts with large crystal sizes. Both catalysts were used in isoeugenol oxidation and vanillyl alcohol to vanillin reactions, with the CuO/MgAl2O4 showing optimum results. This catalyst provided 67% conversion (74% selectivity) after 2 h and this value improved to 81% (selectivity 100%) with the second reaction after 8 h. The CuO/MgFe2O4 catalyst in the first reaction after five hours revealed 53% conversion (47% selectivity) and after eight hours with the second reaction, the conversion value improved to 64% (100% selectivity). In terms of reusability, CuO/MgAl2O4 showed better results than the CuO/MgFe2O4 catalyst, for both reactions.


Assuntos
Óxido de Alumínio/química , Benzaldeídos/síntese química , Compostos Férricos/química , Compostos de Magnésio/química , Óxido de Magnésio/química , Óxido de Alumínio/síntese química , Benzaldeídos/química , Álcoois Benzílicos/química , Catálise , Cobre/química , Eugenol/análogos & derivados , Eugenol/química , Compostos Férricos/síntese química , Compostos de Magnésio/síntese química , Óxido de Magnésio/síntese química , Oxirredução
7.
Molecules ; 24(14)2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31319597

RESUMO

MnFe2O4 NPs are successfully decorated on the surface of SiO2 sheets to form the SiO2-MnFe2O4 composite via one-pot hydrothermal synthesis method. The phase identification, morphology, crystal structure, distribution of elements, and microwave absorbing properties in S-band (1.55~3.4 GHz) of the as-prepared composite were investigated by XRD, SEM, TEM, and Vector Network Analyzer (VNA) respectively. Compared with the pure MnFe2O4 NPs, the as-prepared SiO2-MnFe2O4 composite exhibits enhanced microwave absorption performance in this frequency band due to the strong eddy current loss, better impedance matching, excellent attenuation characteristic, and multiple Debye relaxation processes. The maximum reflection loss of -14.87 dB at 2.25 GHz with a broader -10 dB bandwidth over the frequency range of 1.67~2.9 GHz (1.23 GHz) can be obtained at the thickness of 4 mm. Most importantly, the preparation method used here is relatively simple, hence such composite can be served as a potential candidate for effective microwave absorption in S-band.


Assuntos
Compostos Férricos/síntese química , Compostos de Manganês/síntese química , Micro-Ondas , Dióxido de Silício/síntese química , Compostos Férricos/química , Magnetismo , Compostos de Manganês/química , Estrutura Molecular , Dióxido de Silício/química , Difração de Raios X
8.
J Colloid Interface Sci ; 552: 689-700, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31176052

RESUMO

HYPOTHESIS: Magnetic liposomes are shown to release the entrapped dye once modulated by low frequency AC MF. The mechanism and effectiveness of MF application should depend on lipid composition, magnetic nanoparticles (MNPs) properties, temperature and field parameters. EXPERIMENTS: The study was performed using liposomes of various lipid composition and embedded hydrophobic MNPs. The liposomes structural changes were studied by the transmission electron microscopy (TEM) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and the leakage was monitored by the fluorescent dye release. FINDINGS: Magnetic liposomes exposure to the AC MF resulted in the clustering of the MNPs in the membranes and disruption of the lipid packaging. Addition of cholesterol diminished the dye release from the saturated lipid-based liposomes. Replacement of the saturated lipid for unsaturated one also decreased the dye release. The dye release depended on the strength, but not the frequency of the field. Thus, the oscillating motion of MNPs in AC MF ruptures the gel phase membranes of saturated lipids. As the temperature increases the disruption also increases. In the liquid crystalline membranes formed by unsaturated lipids the deformations and defects created by mechanical motion of the MNPs are more likely to heal and results in decreased release.


Assuntos
Compostos Férricos/química , Corantes Fluorescentes/química , Lipídeos/química , Nanopartículas de Magnetita/química , Liberação Controlada de Fármacos , Compostos Férricos/síntese química , Interações Hidrofóbicas e Hidrofílicas , Lipossomos/síntese química , Lipossomos/química , Campos Magnéticos , Tamanho da Partícula , Propriedades de Superfície , Temperatura
9.
Mater Sci Eng C Mater Biol Appl ; 102: 552-557, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147027

RESUMO

Hollow hematite (α-Fe2O3) fine fibers with multiwall structure were synthesized by utilizing a centrifugal spinning technique. Aqueous solutions of polyvinyl pyrrolidone and iron (III) nitrate nonahydrate were prepared and spun into fibers. The precursor fibers were heat treated at 650 °C to form iron oxide fibers. Scanning electron micrographs revealed the formation of iron oxide hollow fibers with multiwall structure with average wall thickness of 55 ±â€¯15 nm and outer fiber diameter of 852 ±â€¯86 nm. The formation of α-Fe2O3 was confirmed by X-ray diffraction analysis and the phase identification was verified by XRD pattern and transmission electron microscopy analysis. These hollow structure α-Fe2O3 fibers have promising uses in important biological processes and biomedical applications.


Assuntos
Centrifugação/métodos , Compostos Férricos/síntese química , Povidona/química , Espectroscopia Fotoeletrônica , Termogravimetria
10.
Dalton Trans ; 48(26): 9490-9515, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31211303

RESUMO

Cancer is a global epidemic and is considered a leading cause of death. Various cancer treatments such as chemotherapy, surgery, and radiotherapy are available for the cure but those are generally associated with poor long-term survival rates. Consequently, more advanced and selective methods that have better outcomes, fewer side effects, and high efficacies are highly in demand. Among these is the use of superparamagnetic iron oxide nanoparticles (SPIONs) which act as an innovative kit for battling cancer. Low cost, magnetic properties and toxicity properties enable SPIONs to be widely utilized in biomedical applications. For example, magnetite and maghemite (Fe3O4 and γ-Fe2O3) exhibit superparamagnetic properties and are widely used in drug delivery, diagnosis, and therapy. These materials are termed SPIONs when their size is smaller than 20 nm. This review article aims to provide a brief introduction on SPIONs, focusing on their fundamental magnetism and biological applications. The quality and surface chemistry of SPIONs are crucial in biomedical applications; therefore an in-depth survey of synthetic approaches and surface modifications of SPIONs is provided along with their biological applications such as targeting, site-specific drug delivery and therapy.


Assuntos
Antineoplásicos/farmacologia , Sistemas de Liberação de Medicamentos , Compostos Férricos/farmacologia , Nanopartículas de Magnetita/química , Neoplasias/tratamento farmacológico , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Compostos Férricos/síntese química , Compostos Férricos/química , Humanos , Neoplasias/diagnóstico
11.
Carbohydr Polym ; 216: 54-62, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31047082

RESUMO

Biodegradable, antimicrobial, and semiconducting cellulosic composite was synthesized by in-situ polymerization of polyaniline in the presence of cellulose. The cobalt ferrite nanoparticles (CFO-NPs) were added during the polymerization process to acquire this composite magnetic property. The CFO-NPs were prepared by sol-gel method with average particles size less than 50 nm. The nanocomposites were characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). In addition, their magnetic, dielectric constant, dielectric loss, and conductivity behaviors were studied. The magnetization (Ms) and conductivity increased up to 3.7 emu/g and 3.5 × 10-3 S/cm, respectively, with increasing CFO-NPs content. The prepared electromagnetic nanocomposite exhibits highly efficient biodegradability and antimicrobial activity against Escherichia coli, Bacillus subtilis, and Candida albicans. The antimicrobial activity increased with increasing CFO-NPs while the biodegradability decreased.


Assuntos
Compostos de Anilina/farmacologia , Celulose/farmacologia , Cobalto/farmacologia , Compostos Férricos/farmacologia , Nanocompostos/química , Nanopartículas/química , Compostos de Anilina/síntese química , Compostos de Anilina/química , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Plásticos Biodegradáveis/síntese química , Plásticos Biodegradáveis/química , Plásticos Biodegradáveis/farmacologia , Candida albicans/efeitos dos fármacos , Celulose/análogos & derivados , Celulose/síntese química , Cobalto/química , Condutividade Elétrica , Escherichia coli/efeitos dos fármacos , Compostos Férricos/síntese química , Compostos Férricos/química , Fenômenos Magnéticos , Tamanho da Partícula
12.
Biomed Res Int ; 2019: 7127869, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31032360

RESUMO

Natural enzyme mimics have attracted considerable attention due to leakage of enzymes and their easy denaturation during their storage and immobilization procedure. Here in this study, for the first time, a new iron oxide hydroxide, ferrihydrite - Fe1.44O0.32 (OH) 3.68 magnetic nanoparticles were synthesized by bacterial strain named Comamonas testosteroni. The characterization of the produced magnetic nanoparticles was confirmed by transmission electron microscopy (TEM), Fourier-transform spectroscopy (FTIR), X-ray diffraction (XRD), and magnetization hysteresis loops. Further, these extracted nanoparticles were proven to have biogenic magnetic behavior and to exhibit enhanced peroxidase-like activity. It is capable of catalyzing the oxidation of 3, 3', 5, 5'-Tetramethylbenzidine (TMB) by H2O2 to produce blue color (typical color reactions). Catalysis was examined to follow Michaelis-Menton kinetics and the good affinity to both H2O2 and TMB. The K m value of the Fe1.44O0.32 (OH) 3.68 with H2O2 and TMB as the substrate was 0.0775 and 0.0155 mM, respectively, which were lower than that of the natural enzyme (HRP). Experiments of electron spin resonance (ESR) spectroscopy proved that the BMNPs could catalyze H2O2 to produce hydroxyl radicals. As a new peroxidase mimetic, the BMNPs were exhibited to offer a simple, sensitive, and selective colorimetric method for determination of H2O2 and glucose and efficiently catalyze the detection of glucose in real blood samples.


Assuntos
Comamonas testosteroni/química , Glucose/química , Peróxido de Hidrogênio/química , Peroxidase/química , Benzidinas/química , Biomimética , Técnicas Biossensoriais , Catálise , Espectroscopia de Ressonância de Spin Eletrônica , Compostos Férricos/síntese química , Compostos Férricos/química , Compostos Férricos/farmacologia , Glucose/isolamento & purificação , Peróxido de Hidrogênio/isolamento & purificação , Cinética , Nanopartículas de Magnetita , Microscopia Eletrônica de Transmissão , Oxirredução/efeitos dos fármacos , Peroxidase/síntese química , Peroxidase/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
13.
Artigo em Inglês | MEDLINE | ID: mdl-30938571

RESUMO

In this study, iron oxide nanoparticles (IO-NPs) with a mean diameter of 102.85 nm were firstly synthesized via a facile green route using Ulva spp. aqueous extract as a bioreductant agent. Then, IO-NPs were loaded into carbonated hydroxyapatite (c-Hap) and the final product was named as the iron oxide nanoparticles loaded carbonated hydroxyapatite (IO-NPs-Lc-Hap). Subsequently, IO-NPs-Lc-Hap was characterized by FT-IR, SEM, XRD and EDX analysis methods. MG colour removal efficiencies of Ulva spp., Hap, IO-NPs and IO-NPs-Lc-Hap materials were also evaluated by adsorption and/or Fenton-like reaction methods. IO-NPs-Lc-Hap with the highest decolourization capacity was chosen as a heterogeneous Fenton-like catalyst for Malachite Green (MG). For Fenton-like decolourization of MG, the optimum H2O2 concentration, initial dye concentration and catalyst concentration were determined to be 30 mM, 100 mg/L and 1.0 g/L, respectively. At these optimum conditions, 100% decolourization efficiency and 33.3% COD removal were obtained. On the other hand, 94% decolourization efficiency and 42% COD removal were achieved for the real textile wastewater at the obtained optimum conditions. The experimental decolourization reaction rate for MG was determined as -rd = 0.0779 [(mg dye0.3) (g cat-0.3) (min-1)] × qt0.7. Also, the catalyst had high decolourization efficiencies at the end of six sequence usages.


Assuntos
Corantes/isolamento & purificação , Durapatita/farmacologia , Compostos Férricos/química , Peróxido de Hidrogênio/química , Ferro/química , Nanopartículas/química , Corantes de Rosanilina/isolamento & purificação , Adsorção , Carbonatos/química , Catálise , Corantes/farmacocinética , Durapatita/química , Compostos Férricos/síntese química , Compostos Férricos/farmacocinética , Corantes de Rosanilina/farmacocinética , Espectroscopia de Infravermelho com Transformada de Fourier , Ulva/química , Ulva/metabolismo , Águas Residuárias/química , Purificação da Água/métodos
14.
Molecules ; 24(5)2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-30823493

RESUMO

Cyclic hydroxamic acids can be viewed as effective binders of soluble iron and can therefore be useful moieties for employing in compounds to treat iron overload disease. Alternatively, they are analogs of bacterial siderophores (iron-scavenging metabolites) and can find utility in designing antibiotic constructs for targeted delivery. An earlier described three-component variant of the Castagnoli-Cushman reaction of homophthalic acid (via in situ cyclodehydration to the respective anhydride) was extended to involve hydroxylamine in lieu of the amine component of the reaction. Using hydroxylamine acetate and O-benzylhydroxylamine was key to the success of this transformation due to greater solubility of the reagents in refluxing toluene (compared to hydrochloride salt). The developed protocol was found suitable for multigram-scale syntheses of N-hydroxy- and N-(benzyloxy)tetrahydroisoquinolonic acids. The cyclic hydroxamic acids synthesized in the newly developed format have been tested and shown to be efficient ligands for Fe3+, which makes them suitable candidates for the above-mentioned applications.


Assuntos
Complexos de Coordenação , Compostos Férricos , Ácidos Hidroxâmicos/química , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Compostos Férricos/síntese química , Compostos Férricos/química , Sideróforos/química
15.
Molecules ; 24(7)2019 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-30925778

RESUMO

Here, we present a comprehensive review on the use of microwave chemistry for the synthesis of iron-oxide nanoparticles focused on molecular imaging. We provide a brief introduction on molecular imaging, the applications of iron oxide in biomedicine, and traditional methods for the synthesis of these nanoparticles. The review then focuses on the different examples published where the use of microwaves is key for the production of nanoparticles. We study how the different parameters modulate nanoparticle properties, particularly for imaging applications. Finally, we explore principal applications in imaging of microwave-produced iron-oxide nanoparticles.


Assuntos
Compostos Férricos/síntese química , Micro-Ondas , Imagem Molecular/métodos , Nanopartículas/química , Animais , Meios de Contraste/química , Humanos , Nanopartículas/ultraestrutura
16.
Mater Sci Eng C Mater Biol Appl ; 99: 1424-1447, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30889678

RESUMO

Recently, the intrinsic enzyme-like activities of some nanoscale materials known as "nanozymes" have become a growing area of interest. Nanosized spinel substituted ferrites (SFs) with general formula of MFe2O4, where M represents a transition metal, are among a group of magnetic nanomaterials attracting researchers' enormous attention because of their excellent catalytic performance, biomedical applications and capability for environmental remediation. Due to their unique nanoscale physical-chemical properties, they have been used to mimic the catalytic activity of natural enzymes such as peroxidases, oxidases and catalases. In addition, various nanocomposite materials based on SFs have been introduced as novel artificial enzymes. This review mainly highlights the synthetic approaches for newly developed SF-nanozymes and also the structural/experimental factors that are effective on the kinetics and catalytic mechanisms of enzyme-like reactions. SF-nanozymes have been found potentially capable of being applied in various fields such as enzyme-free immunoassays and biosensors for colorimetric detection of biological molecules. Therefore, the application of SF nanoparticles, as efficient enzyme mimetics have been detailed discussed.


Assuntos
Óxido de Alumínio/química , Materiais Biomiméticos/síntese química , Enzimas/metabolismo , Compostos Férricos/síntese química , Óxido de Magnésio/química , Nanoestruturas/química , Materiais Biomiméticos/química , Técnicas Biossensoriais , Compostos Férricos/química
17.
Food Chem ; 287: 382-389, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-30857715

RESUMO

A magnetic solid-phase extraction method was developed using maghemite as an efficient sorbent for the separation and preconcentration of antimony prior to its determination by ET-AAS. Maghemite was synthesized through a simple method and characterized by XRD, FT-IR and SEM. Various factors affecting maghemite synthesis, separation and preconcentration of antimony such as desorption solvent type, concentration and volume, desorption temperature and time, sample pH, amount of sorbent, and extraction temperature and time were optimized. The effects of interfering ions were also investigated. Under optimized conditions, the method exhibited good linearity (r2 > 0.9960). The sorption capacity and enrichment factor (EF) of the method were 37.5 mg g-1 and 242, respectively. The limit of detection (LOD) was 0.03 ng mL-1. The intraday, interday, and batch-to-batch relative standard deviations (%RSDs) were quite reasonable. The proposed method was applied to various real samples and the relative recoveries found were between 95.8 and 104.0 %.


Assuntos
Antimônio/análise , Compostos Férricos/química , Contaminação de Alimentos/análise , Nanopartículas Metálicas/química , Extração em Fase Sólida/métodos , Bebidas/análise , Água Potável/análise , Água Potável/química , Compostos Férricos/síntese química , Concentração de Íons de Hidrogênio , Limite de Detecção , Magnetismo , Microscopia Eletrônica de Varredura , Reprodutibilidade dos Testes , Soluções/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo , Poluentes Químicos da Água/análise , Difração de Raios X
18.
Inorg Chem ; 58(2): 1398-1413, 2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30623648

RESUMO

Fungal denitrification plays a crucial role in the nitrogen cycle and contributes to the total N2O emission from agricultural soils. Here, cytochrome P450 NO reductase (P450nor) reduces two NO to N2O using a single heme site. Despite much research, the exact nature of the critical "Intermediate I" responsible for the key N-N coupling step in P450nor is unknown. This species likely corresponds to a Fe-NHOH-type intermediate with an unknown electronic structure. Here we report a new strategy to generate a model system for this intermediate, starting from the iron(III) methylhydroxylamide complex [Fe(3,5-Me-BAFP)(NHOMe)] (1), which was fully characterized by 1H NMR, UV-vis, electron paramagnetic resonance, and vibrational spectroscopy (rRaman and NRVS). Our data show that 1 is a high-spin ferric complex with an N-bound hydroxylamide ligand that is strongly coordinated (Fe-N distance, 1.918 Å; Fe-NHOMe stretch, 558 cm-1). Simple one-electron oxidation of 1 at -80 °C then cleanly generates the first model system for Intermediate I, [Fe(3,5-Me-BAFP)(NHOMe)]+ (1+). UV-vis, resonance Raman, and Mössbauer spectroscopies, in comparison to the chloro analogue [Fe(3,5-Me-BAFP)(Cl)]+, demonstrate that 1+ is best described as an FeIII-(NHOMe)• complex with a bound NHOMe radical. Further reactivity studies show that 1+ is highly reactive toward NO, a reaction that likely proceeds via N-N bond formation, following a radical-radical-type coupling mechanism. Our results therefore provide experimental evidence, for the first time, that an FeIII-(NHOMe)• electronic structure is indeed a reasonable electronic description for Intermediate I and that this electronic structure is advantageous for P450nor catalysis because it can greatly facilitate N-N bond formation and, ultimately, N2O generation.


Assuntos
Compostos Férricos/metabolismo , NADPH-Ferri-Hemoproteína Redutase/metabolismo , Teoria da Densidade Funcional , Compostos Férricos/síntese química , Compostos Férricos/química , Modelos Moleculares
19.
J Photochem Photobiol B ; 192: 74-82, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30685586

RESUMO

Green synthesis of nanoparticles is one of the promising, ecofriendly and safer methods. Utilizing plant sources as reducing agents will replace the use of toxic chemicals for nanoparticle synthesis. In the present study FeONPs were synthesized using Ruellia tuberosa (RT) leaf aqueous extract, further characterization of FeONPs was performed using UV-vis spectroscopy analysis showing visible peak at 405 nm. The Fourier transform infrared spectroscopy (FTIR) proved the presence of Fe metallic ions. The structural characteristic using Field emission scanning electron microscopy with energy dispersive x-ray spectroscopy (FESEM-EDX) and Transmission electron microscopy (TEM) analysis revealed hexagonal nanorods with agglomeration. Dynamic light scattering (DLS) calculated the average size of FeONPs around 52.78 nm and differential scanning colorimetry (DSC) proved the stability of FeONPs till higher temperature of 165.52 °C. As an application part, the synthesized FeONPs showed potential antibacterial activity as individual and incorporating material over cotton fabrics against Gram negative and Gram positive pathogens. FeONPs showed higher antibacterial activity against Escherichia coli, Klebsiella pneumoniae and lesser antibacterial activity against Staphylococcus aureus. The photocatalytic ability of the synthesized FeONPs was demonstrated by the degrading crystal violet dye under solar irradiation upto 80%. Thus, FeONPs synthesized using Ruellia tuberosa could play a vital role in killing the bacterial pathogens and degrading dye for the bioremediation of wastewater from industrial and domestic sources.


Assuntos
Acanthaceae/química , Antibacterianos/farmacologia , Compostos Férricos/síntese química , Nanopartículas Metálicas/química , Fotólise/efeitos dos fármacos , Extratos Vegetais/química , Biodegradação Ambiental , Catálise/efeitos dos fármacos , Corantes/química , Escherichia coli/efeitos dos fármacos , Química Verde , Klebsiella pneumoniae/efeitos dos fármacos , Águas Residuárias/química
20.
Arch Pharm (Weinheim) ; 352(1): e1800174, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30485473

RESUMO

Heat shock protein 90 (Hsp90) is a validated molecular chaperone considered as the new key recipient for cancer intervention. The current study illustrates the synthesis of novel spirooxindole-dihydropyrimidinones (4a-j) by Fe3 O4 nanoparticles intervened synthesis and their Hsp90 ATPase inhibitory activity was investigated by the malachite green assay. All the compounds in the study demonstrated a moderate to potent ATPase inhibitory profile, with IC50 values ranging from 0.18 to 6.80 µM. Compounds 4j, 4h, 4f, and 4i exhibited maximum inhibitory potential with IC50 values of 0.18, 0.20, 0.35, and 0.55 µM, respectively. They were found to be better than the standard drug, geldanamycin (Hsp9 ATPase inhibition IC50 = 0.90 µM). Compounds 4h and 4j with IC50 values of 22.82 ± 0.532, 20.78 ± 0.234 and 21.32 ± 0.765, 28.43 ± 0.653 µM showed significantly greater potencies against the MCF-7 and HepG2 cell lines, respectively. Compound 4j showed good antioxidant activities in the DPPH test and H2 O2 assay (IC50 = 20.13.23 ± 0.32 and 23.27 ± 0.32 µg/mL) when compared with the standard ascorbic acid (IC50 = 19.16 ± 0.20 and 20.66 ± 1.09 µg/mL). A molecular docking study was performed to observe the binding efficiency and steric interactions of the lead moiety.


Assuntos
Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Oxindois/farmacologia , Pirimidinonas/farmacologia , Compostos de Espiro/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Antioxidantes/síntese química , Antioxidantes/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Compostos Férricos/síntese química , Compostos Férricos/química , Células HEK293 , Células Hep G2 , Humanos , Células MCF-7 , Nanopartículas de Magnetita/química , Simulação de Acoplamento Molecular , Estrutura Molecular , Oxindois/síntese química , Oxindois/química , Tamanho da Partícula , Pirimidinonas/síntese química , Pirimidinonas/química , Compostos de Espiro/síntese química , Compostos de Espiro/química , Relação Estrutura-Atividade , Propriedades de Superfície
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