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Sensors (Basel, Switzerland) Sep 2020Mo-based layered nanostructures are two-dimensional (2D) nanomaterials with outstanding characteristics and very promising electrochemical properties. These materials... (Review)
Review
Mo-based layered nanostructures are two-dimensional (2D) nanomaterials with outstanding characteristics and very promising electrochemical properties. These materials comprise nanosheets of molybdenum (Mo) oxides (MoO and MoO), dichalcogenides (MoS, MoSe, MoTe), and carbides (MoC), which find application in electrochemical devices for energy storage and generation. In this feature paper, we present the most relevant characteristics of such Mo-based layered compounds and their use as electrode materials in electrochemical sensors. In particular, the aspects related to synthesis methods, structural and electronic characteristics, and the relevant electrochemical properties, together with applications in the specific field of electrochemical biomolecule sensing, are reviewed. The main features, along with the current status, trends, and potentialities for biomedical sensing applications, are described, highlighting the peculiar properties of Mo-based 2D-nanomaterials in this field.
Topics: Disulfides; Electrochemical Techniques; Electrodes; Molybdenum; Nanostructures
PubMed: 32967188
DOI: 10.3390/s20185404 -
Molecules (Basel, Switzerland) Jun 2022Molybdenum (Mo) is an essential trace element in all kingdoms of life. Mo is bioavailable as the oxyanion molybdate and gains biological activity in eukaryotes when...
Molybdenum (Mo) is an essential trace element in all kingdoms of life. Mo is bioavailable as the oxyanion molybdate and gains biological activity in eukaryotes when bound to molybdopterin, forming the molybdenum cofactor. The imbalance of molybdate homeostasis results in growth deficiencies or toxic symptoms within plants, fungi and animals. Recently, fluorescence resonance energy transfer (FRET) methods have emerged, monitoring cellular and subcellular molybdate distribution dynamics using a genetically encoded molybdate-specific FRET nanosensor, named MolyProbe. Here, we show that the MolyProbe system is a fast and reliable in vitro assay for quantitative molybdate determination. We added a Strep-TagII affinity tag to the MolyProbe protein for quick and easy purification. This MolyProbe is highly stable, resistant to freezing and can be stored for several weeks at 4 °C. Furthermore, the molybdate sensitivity of the assay peaked at low nM levels. Additionally, The MolyProbe was applied in vitro for quantitative molybdate determination in cell extracts of the plant , the fungus and the yeast . Our results show the functionality of the molybdate transporter MOT1.1 and indicate that FRET-based molybdate detection is an excellent tool for measuring bioavailable Mo.
Topics: Anion Transport Proteins; Arabidopsis; Arabidopsis Proteins; Fluorescence Resonance Energy Transfer; Molybdenum; Neurospora crassa; Saccharomyces cerevisiae
PubMed: 35744816
DOI: 10.3390/molecules27123691 -
Scientific Reports Mar 2018Sulfite oxidase is a mononuclear molybdenum enzyme that oxidises sulfite to sulfate in many organisms, including man. Three different reaction mechanisms have been...
Sulfite oxidase is a mononuclear molybdenum enzyme that oxidises sulfite to sulfate in many organisms, including man. Three different reaction mechanisms have been suggested, based on experimental and computational studies. Here, we study all three with combined quantum mechanical (QM) and molecular mechanical (QM/MM) methods, including calculations with large basis sets, very large QM regions (803 atoms) and QM/MM free-energy perturbations. Our results show that the enzyme is set up to follow a mechanism in which the sulfur atom of the sulfite substrate reacts directly with the equatorial oxo ligand of the Mo ion, forming a Mo-bound sulfate product, which dissociates in the second step. The first step is rate limiting, with a barrier of 39-49 kJ/mol. The low barrier is obtained by an intricate hydrogen-bond network around the substrate, which is preserved during the reaction. This network favours the deprotonated substrate and disfavours the other two reaction mechanisms. We have studied the reaction with both an oxidised and a reduced form of the molybdopterin ligand and quantum-refinement calculations indicate that it is in the normal reduced tetrahydro form in this protein.
Topics: Animals; Chickens; Coenzymes; Hydrogen Bonding; Mechanical Phenomena; Metalloproteins; Models, Molecular; Molecular Dynamics Simulation; Molybdenum; Molybdenum Cofactors; Pteridines; Quantum Theory; Sulfite Oxidase; Sulfites
PubMed: 29549261
DOI: 10.1038/s41598-018-22751-6 -
Nano Letters Jul 2021We present the discovery of a charge density wave (CDW) ground state in heavily electron-doped molybdenum disulfide (MoS). This is the first observation of a CDW in any...
We present the discovery of a charge density wave (CDW) ground state in heavily electron-doped molybdenum disulfide (MoS). This is the first observation of a CDW in any (column 6) transition metal dichalcogenide (TMD). The band structure of MoS is distinct from the and TMDs in which CDWs have been previously observed, facilitating new insight into CDW formation. We demonstrate a metal-insulator transition at 85 K, a 25 meV gap at the Fermi level, and two distinct CDW modulations, (2√3 × 2√3) R30° and 2 × 2, attributable to Fermi surface nesting (FSN) and electron-phonon coupling (EPC), respectively. This simultaneous exhibition of FSN and EPC CDW modulations is unique among observations of CDW ground states, and we discuss this in the context of band folding. Our observations provide a route toward the resolution of controversies surrounding the origin of CDW modulations in TMDs.
Topics: Disulfides; Electrons; Molybdenum
PubMed: 34228455
DOI: 10.1021/acs.nanolett.1c00677 -
Journal of Applied Microbiology Nov 2018To investigate the capabilities of different types of biosurfactants (rhamnolipids, lipopeptides, sophorolipids) to remove metals and carbon from the hazardous spent...
AIMS
To investigate the capabilities of different types of biosurfactants (rhamnolipids, lipopeptides, sophorolipids) to remove metals and carbon from the hazardous spent hydrodesulphurization (HDS) catalyst generated by petroleum refineries.
METHODS AND RESULTS
Biosurfactants were prepared and used to treat spent HDS catalyst. Metal and carbon contents were analysed and compared with those from no-biosurfactant control treatments. All biosurfactant treatments increased carbon loss percentage from the spent HDS catalyst. The lipopeptide treatment LI, containing 17·34 mg ml of crude biosurfactants, caused the highest carbon loss percentage (44·5%). Rhamnolipids were, in general, better than sophorolipids and lipopeptides as metal-removing agents. The metal content decreased as the concentration of rhamnolipids decreased. The R5 treatment, which contained 0·4 mg l of crude rhamnolipids, caused the highest reduction in metal content. Molybdenum, nickle and vanadium contents were reduced by 90, 30 and 70% respectively.
CONCLUSIONS
Biosurfactants might have potential application for metals and coke removal from spent HDS catalysts. The bioleaching capability depends on the type and concentration of the biosurfactant.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study, after further in-depth investigations, might lead to the development of an eco-friendly and economic technology to treat or even regenerate the environmentally hazardous spent HDS catalysts, which are generated in huge amounts by the petroleum refineries.
Topics: Bacillus megaterium; Candida; Catalysis; Glycolipids; Lipopeptides; Metals; Molybdenum; Nickel; Petroleum Pollution; Pseudomonas aeruginosa; Surface-Active Agents; Vanadium
PubMed: 29964351
DOI: 10.1111/jam.14036 -
Environmental Monitoring and Assessment Oct 2014An investigation has been carried out of molybdenum in drinking water from a selection of public supply sources and domestic taps across England and Wales. This was to...
An investigation has been carried out of molybdenum in drinking water from a selection of public supply sources and domestic taps across England and Wales. This was to assess concentrations in relation to the World Health Organization (WHO) health-based value for Mo in drinking water of 70 μg/l and the decision to remove the element from the list of formal guideline values. Samples of treated drinking water from 12 water supply works were monitored up to four times over an 18-month period, and 24 domestic taps were sampled from three of their supply areas. Significant (p < 0.05) differences were apparent in Mo concentration between sources. Highest concentrations were derived from groundwater from a sulphide-mineralised catchment, although concentrations were only 1.5 μg/l. Temporal variability within sites was small, and no seasonal effects (p > 0.05) were detected. Tap water samples collected from three towns (North Wales, the English Midlands, and South East England) supplied uniquely by upland reservoir water, river water, and Chalk groundwater, respectively, also showed a remarkable uniformity in Mo concentrations at each location. Within each, the variability was very small between houses (old and new), between pre-flush and post-flush samples, and between the tap water and respective source water samples. The results indicate that water distribution pipework has a negligible effect on supplied tap water Mo concentrations. The findings contrast with those for Cu, Zn, Ni, Pb, and Cd, which showed significant differences (p < 0.05) in concentrations between pre-flush and post-flush tap water samples. In two pre-flush samples, concentrations of Ni or Pb were above drinking water limits, although in all cases, post-flush waters were compliant. The high concentrations, most likely derived from metal pipework in the domestic distribution system, accumulated during overnight stagnation. The concentrations of Mo observed in British drinking water, in all cases less than 2 μg/l, were more than an order of magnitude below the WHO health-based value and suggest that Mo is unlikely to pose a significant health or water supply problem in England and Wales.
Topics: Drinking Water; England; Environmental Monitoring; Groundwater; Molybdenum; Wales; Water Pollutants, Chemical; Water Pollution, Chemical; Water Supply
PubMed: 25012143
DOI: 10.1007/s10661-014-3863-x -
Advanced Science (Weinheim,... Jan 2022Chemodynamic therapy (CDT) is an emerging treatment that usually employs chemical agents to decompose hydrogen peroxide (HO) into hydroxyl radical (•OH) via Fenton or...
Chemodynamic therapy (CDT) is an emerging treatment that usually employs chemical agents to decompose hydrogen peroxide (HO) into hydroxyl radical (•OH) via Fenton or Fenton-like reactions, inducing cell apoptosis or necrosis by damaging biomacromolecules such as, lipids, proteins, and DNA. Generally, CDT shows high tumor-specificity and minimal-invasiveness in patients, thus it has attracted extensive research interests. However, the catalytic reaction efficiency of CDT is largely limited by the relatively high pH at the tumor sites. Herein, a 808 nm laser-potentiated peroxidase catalytic/mild-photothermal therapy of molybdenum diphosphide nanorods (MoP NRs) is developed to improve CDT performance, and simultaneously achieve effective tumor eradication and anti-infection. In this system, MoP NRs exhibit a favorable cytocompatibility due to their inherent excellent elemental biocompatibility. Upon irradiation with an 808 nm laser, MoP NRs act as photosensitizers to efficiently capture the photo-excited band electrons and valance band holes, exhibiting enhanced peroxidase-like catalytic activity to sustainedly decompose tumor endogenous HO to •OH, which subsequently destroy the cellular biomacromolecules both in tumor cells and bacteria. As demonstrated both in vitro and in vivo, this system exhibits a superior therapeutic efficiency with inappreciable toxicity. Hence, the work may provide a promising therapeutic technique for further clinical applications.
Topics: Animals; Cell Line, Tumor; Combined Modality Therapy; Diphosphates; Disease Models, Animal; Female; Humans; Mice; Mice, Inbred BALB C; Molybdenum; Mouth Neoplasms; Nanotubes; Peroxidase; Photothermal Therapy
PubMed: 35059282
DOI: 10.1002/advs.202101527 -
Biological Trace Element Research Mar 2020Conventional cancer therapies possess a plethora of limitations which led to the awakening of nanotechnology and nanomedicine. However, technological success is widely...
Conventional cancer therapies possess a plethora of limitations which led to the awakening of nanotechnology and nanomedicine. However, technological success is widely dependent on complete understanding of the complexity and heterogeneity of tumor biology on one hand and nanobiointeractions associated with challenges of synthesis, translation, and commercialization on the other. The present study therefore deals with one such targeted approach aiming at synthesizing, characterizing, and understanding the efficacy of molybdenum oxide nanoparticles. The phase structure, morphology, and elemental composition of the synthesized nanoparticles were characterized using Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The cytotoxicity studies revealed that the IC vales of molybdenum trioxide (MoO) particles against skin cancer cells (melanoma and non-melanoma) were around 200-300 μg. The nanoparticles were found to induce mitochondrial-mediated apoptosis driven by the apoptotic genes such as BAX and Bcl. Molybdenum being a cofactor for the majority of metabolic enzymes could have triggered the selective internalization of the nanoparticles which in turn could have modified the granularity of the cytoplasm and subsequently lead to mitochondrial-mediated apoptosis. Further, the anti-angiogenic property of MoO nanoparticles was corroborated using Chick chorioallantoic membrane (CAM) assay and aortic ring assay. Taken together , unraveling the role of MoO nanoparticles in cancer and angiogenesis opens up venues for nano biological intervention of selective cancer cell targeting with minimal damage to the normal cells using natural trace elements that are generally known to influence various metabolic enzymes.
Topics: 3T3 Cells; Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Drug Screening Assays, Antitumor; Humans; Melanoma; Mice; Mitochondria; Molybdenum; Nanoparticles; Neovascularization, Pathologic; Oxides; Skin Neoplasms
PubMed: 31123924
DOI: 10.1007/s12011-019-01742-2 -
Environmental Science and Pollution... Sep 2021Some regions of Argentina are affected by high concentrations of molybdenum, arsenic and vanadium from natural sources in their groundwater. In particular, Mo levels in...
Some regions of Argentina are affected by high concentrations of molybdenum, arsenic and vanadium from natural sources in their groundwater. In particular, Mo levels in groundwater from Eduardo Castex (La Pampa, Argentina) typically exceed the guidelines for drinking water formerly established by WHO at 70 μg/L. Therefore, this study investigated the uptake of Mo in plants, using cress (Lepidium sativum L.) as a model using hydroponic experiments with synthetic solutions and groundwater from La Pampa. Cress grown from control experiments (150 μg/L Mo, pH 7) presented an average Mo concentration of 35.2 mg/kg (dry weight, d.w.), higher than the typical total plant range (0.7-2.5 mg/kg d.w.) in the literature. Using pooled groundwater samples (65.0-92.5 μg/L Mo) from wells of La Pampa (Argentina) as growth solutions resulted in significantly lower cress Mo levels (1.89-4.59 mg/kg d.w.) than were obtained for synthetic solutions of equivalent Mo concentration. This may be due to the high levels in these groundwater samples of As, V, Fe and Mn which are known to be associated with volcanic deposits. This research addressed the hitherto scarcity of data about the effect of various physicochemical parameters on the uptake of Mo in plants.
Topics: Arsenic; Drinking Water; Groundwater; Molybdenum; Water Pollutants, Chemical
PubMed: 33928502
DOI: 10.1007/s11356-021-13902-w -
Frontiers in Cellular and Infection... 2022Periprosthetic infections are an eminent factor in patient care and also having significant economic implications. The number of biofilm-infection related replacement...
Periprosthetic infections are an eminent factor in patient care and also having significant economic implications. The number of biofilm-infection related replacement surgeries is increasing and will continue to do so in the following decades. To reduce both the health burden of the patients and the costs to the healthcare sector, new solutions for implant materials resistant to such infections are necessary. This study researches different surface modifications of cobalt-chromium-molybdenum (CoCrMo) based implant materials and their influence on the development of biofilms. Three smooth surfaces (CoCrMo, CoCrMo TiN, and CoCrMo polished) and three rough surfaces (CoCrMo porous coated, CoCrMo cpTi, and CoCrMo TCP) are compared. The most common infectious agents in periprosthetic infections are and Coagulase-negative (e.g., ), therefore strains of these two species have been chosen as model organisms. Biofilms were grown on material disks for 48 h and cell number, polysaccharide content, and protein contend of the biofilms were measured. Additionally, regulation of genes involved in early biofilm development (, , , , , ; , ) was detected using RT-q-PCR. All results were compared to the base alloy without modifications. The results show a correlation between the surface roughness and the protein and polysaccharide content of biofilm structures and also the gene expression of the biofilms grown on the different surface modifications. This is supported by the significantly different protein and polysaccharide contents of the biofilms associated with rough and smooth surface types. Additionally, early phase biofilm genes (particularly , , and ) are statistically significantly downregulated compared to the control at 48 h on rough surfaces. CoCrMo TiN and polished CoCrMo were the two smooth surface modifications which performed best on the basis of low biofilm content.
Topics: Biofilms; Chromium; Cobalt; Humans; Methicillin-Resistant Staphylococcus aureus; Molybdenum; Staphylococcal Infections; Staphylococcus aureus; Staphylococcus epidermidis
PubMed: 35300379
DOI: 10.3389/fcimb.2022.837124