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1.
Chemosphere ; 287(Pt 2): 132055, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34496336

RESUMO

The photocatalytic performance of a semiconducting catalytic system is strongly influenced by charge-carrier separation rate, charge transport properties, surface area, utilization of light energy, and interface bonding. Herein, a series of bismuth vanadate (BiVO4) samples were prepared via hydrothermal method by changing the volume ratios of ethelene glycol and ethanol as a solvent mixture for bismuth precursors. Further, the optimized BiVO4 sheets with hierarchical morphology were used to construct an interface with rod-like g-C3N4 materials, which was confirmed by HRSEM and HRTEM. Due to the formation of an effective interface bonding between BiVO4/g-C3N4, the photoinduced charge carrier's recombination rate was suppressed as confirmed by the PL analysis. The prepared BiVO4/g-C3N4 sample were used to assess the photodegradation efficiency of Rhodamine B (RhB) under direct sunlight irradiation and the photocatalysts degraded ~92.8% of RhB within 2 h. The TOC measurements revealed a 66.4% mineralization efficiency for RhB. In addition, the radical trapping experiments demonstrated that superoxide and hydroxyl radicals are the main reactive species for the degradation. Based on the experimental evidences, a plausible charge transfer mechanism has been proposed. The enhanced photocatalytic activity has been mainly attributed to the inhibition of the recombination rate, enhanced charge carrier transfer efficiency, and high rate of production of reactive species.


Assuntos
Bismuto , Poluentes Ambientais , Nitrilas , Luz Solar , Vanadatos
2.
Molecules ; 26(20)2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34684806

RESUMO

Disposal of palm oil mill effluent (POME), which is highly polluting from the palm oil industry, needs to be handled properly to minimize the harmful impact on the surrounding environment. Photocatalytic technology is one of the advanced technologies that can be developed due to its low operating costs, as well as being sustainable, renewable, and environmentally friendly. This paper reports on the photocatalytic degradation of palm oil mill effluent (POME) using a BiVO4 photocatalyst under UV-visible light irradiation. BiVO4 photocatalysts were synthesized via sol-gel method and their physical and chemical properties were characterized using several characterization tools including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), surface area analysis using the BET method, Raman spectroscopy, electron paramagnetic resonance (EPR), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The effect of calcination temperature on the properties and photocatalytic performance for POME degradation using BiVO4 photocatalyst was also studied. XRD characterization data show a phase transformation of BiVO4 from tetragonal to monoclinic phase at a temperature of 450 °C (BV-450). The defect site comprising of vanadium vacancy (Vv) was generated through calcination under air and maxima at the BV-450 sample and proposed as the origin of the highest reaction rate constant (k) of photocatalytic POME removal among various calcination temperature treatments with a k value of 1.04 × 10-3 min-1. These findings provide design guidelines to develop efficient BiVO4-based photocatalyst through defect engineering for potential scalable photocatalytic organic pollutant degradation.


Assuntos
Bismuto , Resíduos Industriais/análise , Óleo de Palmeira/isolamento & purificação , Fotólise , Vanadatos , Poluentes Químicos da Água/análise , Bismuto/química , Catálise , Cristalografia por Raios X , Microscopia Eletrônica de Varredura , Análise Espectral Raman , Vanadatos/síntese química , Vanadatos/química , Gerenciamento de Resíduos/métodos
3.
Environ Sci Technol ; 55(19): 12862-12870, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34558891

RESUMO

Vanadium-based catalysts have been extensively applied for the synergistic control of NOx and chlorinated organics. However, how the vanadia species affect the reaction activity and products distribution, and what are the dominant reaction sites of these vanadia species are still unknown. Herein, we investigated the reaction characteristics of monomeric and polymeric vanadate domains for the catalytically synergistic elimination of NOx and chlorobenzene (CB). Density functional theory (DFT) calculations and experimental investigations have been combined to clarify the effects of different vanadyl species on the synergistic reaction. It was noted that the main adsorption site of CB on the monomeric domain was V-OH bond, and that on the polymeric one was V═O bond. The monomeric vanadyl was favorable for converting the Lewis V═O into Brønsted V-OH, which provided sufficient H protons for HCl formation, whereas the polymeric species could effectively retain the V4+/V5+ redox cycle, and yielded superior activity in CB catalytic oxidation (CBCO) reaction. However, the abundant oxygen vacancies and the inclined accumulation of Cl by forming the V-Cl bands led to significant polychlorinated byproducts on the polymeric vanadyl catalysts. Our work gives the first insight into different vanadate domain effects on the synergistic reaction, and is expected to provide theoretical basis for efficient design of the vanadium-based catalysts toward multipollutants elimination.


Assuntos
Titânio , Vanadatos , Catálise , Oxirredução
4.
Biomaterials ; 277: 121130, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34534862

RESUMO

Conventional photothermal therapy (PTT) is insufficient to induce a strong and potent anti-tumor immune response. Herein, we present a vanadyl nanocomplex, which simultaneously serves as a photothermal agent (PTA) and an immunogenic cell death (ICD) inducer to enhance the anti-tumor immunity of PTT. The vanadyl nanocomplex (STVN) is constructed via facile one-step coordination assembly under ambient conditions. STVN not only has a strong and stable photothermal effect under near-infrared (NIR) irradiation, but also can cause severe endoplasmic reticulum (ER) stress by itself, leading to ICD and activating the systemic immune responses. In the absence of any adjuvants, NIR-irradiated STVN almost completely ablates primary tumors and simultaneously inhibits distant tumors in mice bearing bilateral melanoma. Meanwhile, the intratumorally injected STVN combined with NIR effectively suppressed melanoma lung metastasis as well as tumor recurrence, displaying that local STVN-mediated PTT could trigger a systemic anti-tumor immunity. Therefore, STVN, as a novel immunogenicity-enhanced PTA, affords a "one stone two birds" strategy for improved photothermia-induced cancer immunotherapy.


Assuntos
Antineoplásicos , Vanadatos , Animais , Linhagem Celular Tumoral , Imunoterapia , Camundongos , Recidiva Local de Neoplasia , Fototerapia
5.
Nat Commun ; 12(1): 5254, 2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34489436

RESUMO

Pdr5, a member of the extensive ABC transporter superfamily, is representative of a clinically relevant subgroup involved in pleiotropic drug resistance. Pdr5 and its homologues drive drug efflux through uncoupled hydrolysis of nucleotides, enabling organisms such as baker's yeast and pathogenic fungi to survive in the presence of chemically diverse antifungal agents. Here, we present the molecular structure of Pdr5 solved with single particle cryo-EM, revealing details of an ATP-driven conformational cycle, which mechanically drives drug translocation through an amphipathic channel, and a clamping switch within a conserved linker loop that acts as a nucleotide sensor. One half of the transporter remains nearly invariant throughout the cycle, while its partner undergoes changes that are transmitted across inter-domain interfaces to support a peristaltic motion of the pumped molecule. The efflux model proposed here rationalises the pleiotropic impact of Pdr5 and opens new avenues for the development of effective antifungal compounds.


Assuntos
Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Trifosfato de Adenosina/metabolismo , Domínio Catalítico , Microscopia Crioeletrônica , Detergentes/química , Farmacorresistência Fúngica/genética , Pleiotropia Genética , Hidrólise , Mutação , Conformação Proteica , Domínios Proteicos , Rodaminas/química , Rodaminas/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Vanadatos/química , Vanadatos/metabolismo
6.
Int J Mol Sci ; 22(18)2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34576048

RESUMO

Oxidative stress plays an important role in the pathogenesis of many serious diseases, including cancer, atherosclerosis, coronary artery disease, Parkinson's disease, Alzheimer's disease, stroke and myocardial infarction. In the body's natural biochemical processes, harmful free radicals are formed, which can be removed with the help of appropriate enzymes, a balanced diet or the supply of synthetic antioxidant substances such as flavonoids, vitamins or anthocyanins to the body. Due to the growing demand for antioxidant substances, new complex compounds of transition metal ions with potential antioxidant activity are constantly being sought. In this study, four oxovanadium(IV) and dioxovanadium(V) dipicolinate (dipic) complexes with 1,10-phenanthroline (phen), 2,2'-bipyridyl (bipy) and the protonated form of 2-phenylpyridine (2-phephyH): (1) [VO(dipic)(H2O)2]·2 H2O, (2) [VO(dipic)(phen)]·3 H2O, (3) [VO(dipic)(bipy)]·H2O and (4) [VOO(dipic)](2-phepyH)·H2O were synthesized including one new complex, so far unknown and not described in the literature, i.e., [VOO(dipic)](2-phepyH)·H2O. The oxovanadium(IV) dipicolinate complexes with 1,10-phenanthroline and 2,2'-bipyridyl have been characterized by several physicochemical methods: NMR, MALDI-TOF-MS, IR, but new complex [VOO(dipic)](2-phepyH)·H2O has been examined by XRD to confirm its structure. The antioxidant activities of four complexes have been examined by the nitrotetrazolium blue (NBT) method towards superoxide anion. All complexes exhibit high reactivity with superoxide anion and [VOO(dipic)](2-phepyH)·H2O has higher antioxidant activity than L-ascorbic acid. Our studies confirmed that high basicity of the auxiliary ligand increases the reactivity of the complex with the superoxide radical.


Assuntos
Estresse Oxidativo/efeitos dos fármacos , Óxidos/química , Ácidos Picolínicos/química , Urânio/química , Vanadatos/química , Antioxidantes/química , Antioxidantes/farmacologia , Ácido Ascórbico/química , Complexos de Coordenação/química , Ligantes , Superóxidos/química
7.
Environ Pollut ; 289: 117839, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34340179

RESUMO

Indigenous microbial consortia are closely associated with soil inherent components including nutrients and minerals. Although indigenous microbial consortia present great prospects for bioremediation of vanadate [V(V)] contaminated soil, influences of some key components, such as available phosphorus (AP), on V(V) biodetoxification are poorly understood. In this study, surface soils sampled from five representative vanadium smelter sites were employed as inocula without pretreatment. V(V) removal efficiency ranged from 81.7 ± 1.4% to 99.5 ± 0.2% in batch experiment, and the maximum V(V) removal rates were positively correlated with AP contents. Long-term V(V) removal was achieved under fluctuant hydrodynamic and hydrochemical conditions in column experiment. Geobacter and Bacillus, which were found in both original soils and bioreactors, catalytically reduced V(V) to insoluble tetravalent vanadium. Phosphate-solubilizing bacterium affiliated to Gemmatimonadaceae were also identified abundantly. Microbial functional characterization indicated the enrichment of phosphate ABC transporter, which could accelerate V(V) transfer into intercellular space for efficient reduction due to the structural similarity of V(V) and phosphate. This study reveals the critical role of AP in microbial V(V) decontamination and provides promising strategy for in situ bioremediation of V(V) polluted soil.


Assuntos
Poluentes do Solo , Solo , Biodegradação Ambiental , Descontaminação , Consórcios Microbianos , Fósforo , Microbiologia do Solo , Poluentes do Solo/análise , Vanadatos
8.
J Colloid Interface Sci ; 603: 666-684, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34225071

RESUMO

Herein, a dual Z-scheme heterojunction photocatalyst consisting of Co3O4, CuBi2O4, and SmVO4 for carbamazepine (CBZ) degradation was synthesised and characterised by XRD, FTIR, UV-Vis DRS, XPS, FE-SEM, and TEM. The reduction in electron-hole recombination was evaluated by PL, LSV, and EIS analysis. The heterojunction, Co3O4/CuBi2O4/SmVO4 (CCBSV) showed enhanced photocatalytic activity of 76.1% ± 3.81 CBZ degradation under visible light irradiation, ascribed to the improved interfacial contact, visible light capturing ability, and enhanced electron-hole separation and transportation through the formation of Z-scheme heterojunction. The formation of dual Z-scheme was confirmed by active radical experiments and XPS analysis that helped to prose the mechanism of degradation. The catalyst showed sustained stability after 4 cycles of reuse. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) was employed to identify the degradation by-products of CBZ, and a possible mechanistic degradation pathway was proposed. This study provided an insight into the development of efficient dual Z-scheme heterojunction photocatalyst for remediation of CBZ which can be extended to other organic pollutants.


Assuntos
Cobre , Vanadatos , Bismuto , Carbamazepina , Cobalto , Luz , Óxidos , Samário
9.
Int J Radiat Biol ; 97(9): 1241-1251, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34125648

RESUMO

PURPOSE: Our previous study indicated that sodium orthovanadate (vanadate), a strong inhibitor of p53, effectively suppressed the lethality from the hematopoietic (HP) and gastrointestinal (GI) syndromes after 12 Gy total-body irradiation (TBI) in mice. This conclusion, however, was inconsistent with the fact that p53 plays a radioprotective role in the intestinal epithelium. The death after TBI of around 12 Gy was attributed to a combined effect of HP and GI syndromes. To verify the effect from prophylactic administration of p53 inhibitor on protection of HP and GI syndromes, in this study, the radioprotective effects from vanadate were investigated in TBI and lower half-body irradiation (partial-body irradiation: PBI) mouse models. METHODS: Female ICR mice were given a single injection of vanadate or vehicle, followed by a lethal dose of TBI or PBI. Radioprotective effects of vanadate against the irradiations were evaluated by analyzing survival rate, body weight, hematopoietic parameters, and histological changes in the bone marrow and intestinal epithelium. RESULTS: TBI-induced HP syndrome was effectively suppressed by vanadate treatment. After TBI, the vanadate-treated mice retained better bone marrow cellularity and showed markedly higher survival rate compared to the vehicle-treated animals. In contrast, vanadate did not relieve loss of intestinal crypts and failed to rescue mice from GI death after PBI. CONCLUSION: Vanadate is a p53 inhibitor that has been shown to be beneficial as a radiation protective agent against HP but was not effective in protecting against acute GI radiation injury.


Assuntos
Protetores contra Radiação/química , Protetores contra Radiação/farmacologia , Sódio/química , Vanadatos/química , Vanadatos/farmacologia , Irradiação Corporal Total/efeitos adversos , Animais , Medula Óssea/efeitos da radiação , Relação Dose-Resposta à Radiação , Trato Gastrointestinal/efeitos da radiação , Camundongos , Camundongos Endogâmicos ICR , Proteína Supressora de Tumor p53/metabolismo
10.
ACS Appl Mater Interfaces ; 13(24): 29179-29186, 2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34101420

RESUMO

This research put forward a novel split-type electrochemical (EC) immunosensor which integrated the controlled-release strategy with EC detection for application in the field of biosensing. Concretely, ascorbic acid (AA) was packaged in a cadmium sulfide (CdS)-capped spherical mesoporous bioactive glass (SBG) nanocarrier (SBGCdS) on account of encapsulation technology. To reduce the complexity of the bioanalysis, the detection antibody-labeled SBGCdS-AA bioconjugate was applied in a 96-well microplate for the immunoreaction process, which is independent of the EC determination procedure. Thus, the immune interference and steric hindrance caused by the accumulation of nanomaterials on the electrode could be minimized. Subsequently, AA was released efficiently via the destruction effect of dithiothreitol on the disulfide bond. In addition, for the as-prepared FcAI/l-Cys/gold nanoparticles (GNPs)/porous BiVO4 (p-BVO)/ITO EC sensing platform in the detection solution, the synergetic catalysis of Fc and GNPs/p-BVO toward the oxidation of the released AA could be realized, which triggered AA-mediated significant signal magnification throughout this study. In particular, p-BVO with an ordered nanoarray structure could accelerate the electron transfer to assist in sensitivity improvement of this system. This novel biosensor was capable of assaying the neuron-specific enolase (NSE) biomarker sensitively, from which a linear range of 0.001-100 ng/mL was derived along with a low detection limit of 1.08 pg/mL. An innovative way could be paved in the bioanalysis of NSE and other biomarkers.


Assuntos
Ácido Ascórbico/química , Imunoensaio/métodos , Nanopartículas Metálicas/química , Fosfopiruvato Hidratase/sangue , Anticorpos Imobilizados/imunologia , Biomarcadores/sangue , Técnicas Biossensoriais/métodos , Bismuto/química , Compostos de Cádmio/química , Técnicas Eletroquímicas , Ouro/química , Humanos , Limite de Detecção , Fosfopiruvato Hidratase/imunologia , Porosidade , Sulfetos/química , Vanadatos/química
11.
Water Sci Technol ; 83(11): 2629-2639, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34115618

RESUMO

Organic esters of phosphoric acid and other organophosphorous compounds are enzymatically hydrolyzed during wastewater treatment by microbial phosphoesterases, especially by phosphomonoesterase (phosphatase). For physiological reasons, the enzyme is inhibited by its main inorganic reaction product, ortho-phosphate. It is known that oxyanions of transition metals, resembling the molecular topology of ortho-phosphate, e.g. vanadate and tungstate, are more potent inhibitors for microbial alkaline phosphatase than phosphate. To proof this effect for activated sludge, a multitude of samples from a communal wastewater treatment plant was exposed at pH values from 7.00 to 8.50 to tungstate, vanadate, and molybdate. Inhibition effects were determined by a sensitive fluorimetric microplate assay and characteristic parameters (IC50 and IC20 concentrations) were deduced from modelled dose-response functions. Mean inhibitor concentrations (in brackets: ranges) causing 50% inactivation (IC50) at pH 7.50 were 2.5 (1.3-4.1) µM tungstate, 2.9 (1.6-5.5) µM vanadate, and 41.4 (33.6-56.7) µM molybdate. Vanadate and tungstate concentrations between 0.6 and 0.7 µM provoked a 20% (IC20) inhibition. The inhibition efficiency of tungstate and molybdate decreased with increasing pH, whereas vanadate reacted pH independently. These results underline the necessity to consider enzyme inhibition assessing the limitations and potentials of biological wastewater treatment processes.


Assuntos
Monoéster Fosfórico Hidrolases , Esgotos , Cinética , Molibdênio , Fosfatos , Vanadatos
12.
Int J Biol Macromol ; 185: 40-48, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34144065

RESUMO

It is well known that the chemical structure of polysaccharides is important to their final biological effect. In this study we investigated the cytotoxic effect of xyloglucan from Copaifera langsdorffii seeds (XGC) and its complex with oxovanadium (XGC:VO) on hepatocellular carcinoma cells (HepG2). After 72 h of incubation, XGC and XGC:VO (200 µg/mL) reduced cell viability in ~20% and ~40%, respectively. At same conditions, only XGC:VO increased in ~20% the LDH enzyme release. In permeabilized cells, incubated with XGC and XGC:VO (200 µg/mL) for 72 h, NADH oxidase activity was reduced by ~45% with XGC and XGC:VO. The succinate oxidase activity was reduced by ~35% with XGC and ~65% with XGC:VO, evidencing that polysaccharide complexation with vanadium could intensify its effects on the respiratory chain. According to this result, the mitochondrial membrane potential was also reduced by ~9% for XGC and ~30% for XGC:VO, when compared to the control group. Interestingly, ATP levels were more elevated for XGC:VO in respect to XGC, probably due the enhance in glycolytic flux evidenced by increased levels of lactate. These results show that the xyloglucan complexation with oxovanadium (IV/V) potentiates the cytotoxic effect of the native polysaccharide, possibly by impairment of oxidative phosphorylation.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Hepatocelular/metabolismo , Fabaceae/química , Glucanos/farmacologia , Neoplasias Hepáticas/metabolismo , Vanadatos/química , Xilanos/farmacologia , Antineoplásicos/química , Carcinoma Hepatocelular/tratamento farmacológico , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glucanos/química , Células Hep G2 , Humanos , L-Lactato Desidrogenase/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Complexos Multienzimáticos/metabolismo , NADH NADPH Oxirredutases/metabolismo , Fosforilação Oxidativa/efeitos dos fármacos , Oxirredutases/metabolismo , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Xilanos/química
13.
Chemosphere ; 275: 130115, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33984904

RESUMO

Aquaculture and farming industries have been seriously threatened by the illegal use of antibiotics as feed-additives to benefit the animal growth. Although various conventional chemical sensing approaches have been widely explored for the trace-level detection of antibiotics, the effective and accurate monitoring techniques are still highly demanded. Herein, we propose a novel surface-enhanced Raman scattering (SERS) substrate with the heterogeneous integration of silver nanoparticles (Ag NPs) on silver vanadate nanorods (ß-AgVO3 NRs) for the ultrasensitive detection of popular antibiotic, chloramphenicol (CAP). The photochemical decoration of Ag NPs on the surface of ß-AgVO3 NRs remarkably enhances the Raman signal intensity of CAP molecules by the synergistic action of the mechanisms of electromagnetic and chemical enhancement. The structural features of Ag-NPs@ß-AgVO3-NRs favor the formation of hotspots at the interface between NPs and NRs by enhanced surface area and numerous active sites for the interaction with CAP molecules. The SERS measurement of CAP molecules on the Ag-NPs@ß-AgVO3-NRs shows a trace-level limit of detection (10-10 M), high uniformity (5.29%), good reproducibility (3.89%), and high analytical enhancement factor (2.05 × 108). The proposed SERS substrate possesses excellent detection ability in monitoring real samples like tap water, milk and eye drops.


Assuntos
Nanopartículas Metálicas , Nanotubos , Animais , Cloranfenicol , Reprodutibilidade dos Testes , Prata , Compostos de Prata , Análise Espectral Raman , Vanadatos
14.
Chem Biol Interact ; 344: 109510, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33974899

RESUMO

The problem of chemoresistance development is an inescapable flipside of modern oncotherapy, in particular for сolorectal cancer patients. The search for or development of drugs effective against resistant tumors involves the use of model resistant cell lines in vitro. To obtain such lines, we reproduced the development of chemoresistance of human colon adenocarcinoma cells under the treatment with drugs of different mechanisms, a cytostatic (paclitaxel) and a targeted agent (Nutlin-3a, an inhibitor of p53-Mdm2 protein-protein interaction). In each case, we gradually increased the content of the substance in the medium, starting from effective concentrations that do not cause total cell death. When studying the lines resistant to the corresponding drug, we noted a reduced sensitivity to the drug of another mechanism of action. Analysis of the original and resistant lines showed that the cells use the universal efflux defense mechanism. The observed effect can be partially neutralized using inhibitors of the ABC transport proteins, including P-glycoprotein, known for its oncoprotective function. The role of the latter was confirmed by real-time RT-PCR and Western blotting.


Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Imidazóis/farmacologia , Paclitaxel/farmacologia , Piperazinas/farmacologia , Quinolinas/farmacologia , Vanadatos/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Transporte Biológico/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Células HCT116 , Humanos , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores
15.
J Mater Chem B ; 9(23): 4663-4669, 2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34032252

RESUMO

Due to their specific spinel structure, ternary oxides with multi-catalytic sites on a highly active exposed surface are recommended as alternative bio-catalysts. Spinel zinc vanadate with two-dimensional nanosheets (Zn3V3O8 NSs) was synthesised using a one-step hydrothermal route with CTAB and glycine as a bi-surfactant, where each NS has a thin thickness (25 nm) and wide cross section (2 µm). As a key parameter for peroxidase-like activity, the Michaelis-Menten constant (Km) for Zn3V3O8 NSs was calculated to be 0.271 mM with TMB and 1.317 mM with H2O2 at optimum conditions, indicating a higher affinity for the exposed (011) facet towards horseradish peroxidases. This affinity is related to the geometric matching between V4+ active sites and the terminal amino groups of TMB. The V4+ ions on the (011) facet act as dangling bonds and readily react with H2O2 in a Fenton-like reaction. The peroxidase-like activity for Zn3V3O8 NSs is verified by the formation of [V(IV)-OO˙] by the ˙O2- and V5+ near V4+ sites, but oxidase activity for Zn3V3O8 NSs. Based on the peroxidase-like activity, Zn3V3O8 NSs were used as a colorimetric glucose sensor with a wide linear range from 0.01 to 0.5 mM and a detection limit (LOD = 3σ/S) of 2.81 × 10-7 M. The colorimetric sensor also exhibited high accuracy and selectivity in synthetic perspiration samples.


Assuntos
Colorimetria/métodos , Glucose/análise , Nanoestruturas/química , Peroxidases/química , Vanadatos/química , Compostos de Zinco/química , Limite de Detecção , Especificidade por Substrato
16.
Biochimie ; 186: 43-50, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33865903

RESUMO

Metal ions and metal complexes are important components of nucleic acid biochemistry, participating both in regulation of gene expression and as therapeutic agents. Three new transition metal complexes of copper(II), zinc(II) and oxidovanadium(IV) with a ligand derived from o-vanillin and thiophene were previously synthesized and their antitumor properties were studied in our laboratory. To elucidate some molecular mechanisms tending to explain the cytotoxic effects observed over tumor cells, we investigated the interaction of these complexes with DNA by gel electrophoresis, UV-Vis spectroscopy, docking studies and molecular dynamics simulations. Our spectroscopy and computational results have shown that all of them were able to bind to DNA, Cu(II) complex is located in the minor groove while Zn(II) and oxidovanadium(IV) complexes act as major groove binding molecules. Interestingly, only the Cu(II) complex caused double-strand DNA nicks, consistent with its higher cytotoxic activities previously observed in tumor cell lines. We propose that the DNA-complex interaction destabilize the molecule either disrupting the phosphodiester bonds or impairing DNA replication, giving those complexes strong antitumor potential.


Assuntos
Cobre/química , DNA/química , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Vanadatos/química , Zinco/química , Bases de Schiff
17.
J Mater Chem B ; 9(13): 3038-3046, 2021 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-33885665

RESUMO

Deep-tissue fluorescence imaging remains a major challenge as there is limited availability of bright biocompatible materials with high photo- and chemical stability. Contrast agents with emission wavelengths above 1000 nm are most favorable for deep tissue imaging, offering deeper penetration and less scattering than those operating at shorter wavelengths. Organic fluorophores suffer from low stability while inorganic nanomaterials (e.g. quantum dots) are based typically on heavy metals raising toxicity concerns. Here, we report scalable flame aerosol synthesis of water-dispersible Ba3(VO4)2 nanoparticles doped with Mn5+ which exhibit a narrow emission band at 1180 nm upon near-infrared excitation. Their co-synthesis with Bi2O3 results in even higher absorption and ten-fold increased emission intensity. The addition of Bi2O3 also improved both chemical stability and cytocompatibility by an order of magnitude enabling imaging deep within tissue. Taken together, these bright particles offer excellent photo-, chemical and colloidal stability in various media with cytocompatibility to HeLa cells superior to existing commercial contrast agents.


Assuntos
Materiais Biocompatíveis/química , Bismuto/química , Meios de Contraste/química , Manganês/química , Óxidos/química , Vanadatos/química , Células HeLa , Humanos , Raios Infravermelhos , Nanopartículas/química , Imagem Óptica
18.
ACS Appl Mater Interfaces ; 13(15): 17586-17598, 2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33847119

RESUMO

Exploring active and ecological materials for the restoration of complex pollution system is highly desired. This study presents a facile defect-tailoring strategy for combined pollutants purification with BiVO4 photocatalysis in which the jointed synchronous reaction of oxidation and reduction is integrated instead of the sequential reaction in two individual systems. XPS and EPR reveal that BiVO4 with a suitable oxygen vacancies (OVs) concentration and distribution exhibits superior photocatalytic activity under the coexistence of TC-HCl and Cr(VI) with Cr(VI) reduction efficiency increased by 71 times compared with the individual Cr(VI) system along with TC-HCl removal efficiency comparable to a single TC-HCl system. The mechanism of synchronous redox reactions mediated by surface OVs is revealed by comprehensive characterization together with reaction kinetic analysis, and the electronic band structure adjustment induced by the OVs variation is confirmed. Active species identification tests and intermediate product analysis confirm that singlet oxygen (1O2) accounts for the selective oxidation of TC-HCl, while electrons dominate the reduction of Cr(VI), under a coexistent environment. The influence of water quality parameters (e.g., pH, cations, anions, and organic substances) on the photocatalytic activity is investigated considering the complexity of the real aquatic environment. Importantly, toxicity assessment with Gram-negative strain E. coli as a model bacterium validates that the toxicity of the intermediates can be reduced to low or even ultralow levels. This work is dedicated to the mechanistic study of defect photocatalysis over BiVO4 and provides a jointed synchronous reaction system for combined pollutant purification.


Assuntos
Bismuto/química , Bismuto/toxicidade , Cromatos/química , Processos Fotoquímicos , Vanadatos/química , Vanadatos/toxicidade , Relação Dose-Resposta a Droga , Escherichia coli/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Oxirredução
19.
Water Environ Res ; 93(10): 2010-2024, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33837607

RESUMO

A novel BiVO4 /Cu/g-C3 N4 heterostructure photocatalyst was synthesized by thermal condensation, hydrothermal, and in situ precipitation method. The microscopic morphology and chemical composition of the synthesized samples were analyzed by XRD, SEM, FT-IR, XPS, and other characterizations. BiVO4 /Cu/g-C3 N4 (BiVO4 /Cu:g-C3 N4 mass ratio was 1:1) photocatalyst had the optimal photocatalytic degradation activity for tetracycline (TC) wastewater under visible light irradiation (120 min, 74.8%). The introduction of Cu and Z-scheme heterojunction was further confirmed by UV-vis, PL, EIS, and capture mechanism analysis, which effectively accelerated the separation and transfer rate of photogenerated electron holes and enhanced the strong oxidation of h+ and •O2 - active species. BiVO4 /Cu/g-C3 N4 heterojunction photocatalytic material has potential application value in the removal of refractory pollutants in wastewater. PRACTITIONER POINTS: A novel Z-scheme BiVO4 /Cu/g-C3 N4 photocatalyst with excellent photocatalytic activities and stability was prepared to treat tetracycline (TC) wastewater. 1:1 CBCN (BiVO4 /Cu:g-C3 N4 mass ratio was 1:1) photocatalyst exhibited the highest photocatalytic performance for TC wastewater. The Z-scheme heterojunction and Cu act as the interfacial charge transfer medium accelerated the transfer and separation of carriers.


Assuntos
Luz , Vanadatos , Antibacterianos , Catálise , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Inorg Chem ; 60(9): 6585-6599, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33878862

RESUMO

Silver vanadate nanorods (ß-AgVO3) with silver nanoparticles (Ag-NPs) decorated on the surface of the rods were synthesized by using simple hydrothermal technique and later anchored onto nitrogen-doped reduced graphene oxide (N-rGO) to make a novel nanocomposite. Experimental analyses were carried out to identify the electronic configuration by X-ray diffraction analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analysis, which revealed monoclinic patterns of the C12/m1 space group with Wulff construction forming beta silver vanadate (ß-AgVO3) crystals with optical density and phase transformations. Ag nucleation showed consistent results with metallic formation and electronic changes occurring in [AgO5] and [AgO3] clusters. Transmission electron microscopy and field-emission scanning electron microscopy with elemental mapping and EDX analysis of the morphology reveals the nanorod structure for ß-AgVO3 with AgNPs on the surface and sheets for N-rGO. Additionally, a novel electrochemical sensor is constructed by using Ag/AgVO3/N-rGO on screen-printed carbon paste electrodes for the detection of antiviral drug levofloxacin (LEV) which is used as a primary antibiotic in controlling COVID-19. Using differential pulse voltammetry, LEV is determined with a low detection limit of 0.00792 nm for a linear range of 0.09-671 µM with an ultrahigh sensitivity of 152.19 µA µM-1 cm-2. Furthermore, modified electrode performance is tested by real-time monitoring using biological and river samples.


Assuntos
Espectroscopia Dielétrica/instrumentação , Espectroscopia Dielétrica/métodos , Levofloxacino/análise , Nanocompostos/química , Antivirais/análise , Antivirais/sangue , Antivirais/urina , Carbono/química , Eletrodos , Grafite/química , Humanos , Levofloxacino/sangue , Levofloxacino/urina , Limite de Detecção , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Nanotubos/química , Espectroscopia Fotoeletrônica , Prata/química , Compostos de Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Comprimidos , Vanadatos/química , Difração de Raios X
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