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Biosensors Nov 2023Azithromycin (AZY) is a well-known top-prioritized antibiotic and is used by humans in strong concentrations. However, the side effects of the AZY antibiotic may cause...
Azithromycin (AZY) is a well-known top-prioritized antibiotic and is used by humans in strong concentrations. However, the side effects of the AZY antibiotic may cause some serious and significant damage to humans and the environment. Thus, there is a need to develop effective and sensitive sensors to monitor accurate concentrations of AZY. In the last decade, electrochemistry-based sensors have received enormous attention from the scientific community because of their high sensitivity, selectivity, cost-effectiveness, fast response, rapid detection response, simple fabrication, and working principle. It is important to mention that electrochemical sensors rely on the properties of electrode modifiers. Hence, the selection of electrode materials is of great significance when designing and developing efficient and robust electrochemical sensors. In this study, we fabricated an AZY sensor by utilizing a molybdenum disulfide/titanium aluminum carbide (MoS@TiAlC) composite as the electrode material. The MoS@TiAlC composite was synthesized via a simple sonication process. The synthesized MoS@TiAlC composite was characterized using a powder X-ray diffraction (XRD) method to examine the phase purity and formation of the MoS@TiAlC composite. Scanning electron microscopy (SEM) was used to study the surface morphological features of the prepared MoS@TiAlC composite, whereas energy dispersive X-ray spectroscopy (EDAX) was adopted to determine the elemental composition of the prepared MoS@TiAlC composite. The glassy carbon (GC) electrode was modified with the prepared MoS@TiAlC composite and applied as the AZY sensor. The sensing performance of the MoS@TiAlC composite-modified GC electrode was studied using linear sweep voltammetry. The sensor demonstrated excellent performance when determining AZY and showed a good detection limit of 0.009 µM with a sensitivity of 6.77 µA/µM.cm.
Topics: Humans; Molybdenum; Azithromycin; Carbon; Microscopy, Electron, Scanning; Anti-Bacterial Agents; Electrodes; Limit of Detection; Electrochemical Techniques
PubMed: 37998161
DOI: 10.3390/bios13110986 -
Advanced Science (Weinheim,... Sep 2023Sonodynamic therapy (SDT) has been widely reported as a noninvasive and high-penetration therapy for cancer; however, the design of an efficient sonosensitizer remains...
Sonodynamic therapy (SDT) has been widely reported as a noninvasive and high-penetration therapy for cancer; however, the design of an efficient sonosensitizer remains an urgent need. To address this issue, molybdenum disulfide nanoflowers (MoS NF) as piezo-sonosensitizers and introduced sulfur vacancies on the MoS NF (Sv-MoS NF) to improve their piezoelectric property for cancer therapy are designed. Under ultrasonic mechanical stress, the Sv-MoS NF resulted in piezoelectric polarization and band tilting, which enhanced the charge carrier separation and migration. This resulted in an improved catalytic reaction for reactive oxygen species (ROS) production, ultimately enhancing the SDT performance. Thanks to the high efficiency of ROS generation, the Sv-MoS NF have demonstrated a good anticancer effect in vitro and in vivo. Following a systematic evaluation, Sv-MoS NF also demonstrated good biocompatibility. This novel piezo-sonosensitizer and vacancy engineering strategy provides a promising new approach for achieving efficient SDT.
Topics: Humans; Molybdenum; Reactive Oxygen Species; Ultrasonic Therapy; Neoplasms
PubMed: 37395638
DOI: 10.1002/advs.202301152 -
International Journal of Molecular... Jul 2019Dimethyl sulfoxide reductases (DMSO) are molybdoenzymes widespread in all domains of life. They catalyse not only redox reactions, but also hydroxylation/hydration and... (Review)
Review
Dimethyl sulfoxide reductases (DMSO) are molybdoenzymes widespread in all domains of life. They catalyse not only redox reactions, but also hydroxylation/hydration and oxygen transfer processes. Although literature on DMSO is abundant, the biological significance of these enzymes in anaerobic respiration and the molecular mechanisms beyond the expression of genes coding for them are still scarce. In this review, a deep revision of the literature reported on DMSO as well as the use of bioinformatics tools and free software has been developed in order to highlight the relevance of DMSO reductases on anaerobic processes connected to different biogeochemical cycles. Special emphasis has been addressed to DMSO from extremophilic organisms and their role in nitrogen cycle. Besides, an updated overview of phylogeny of DMSOs as well as potential applications of some DMSO reductases on bioremediation approaches are also described.
Topics: Coenzymes; Extremophiles; Iron-Sulfur Proteins; Isoenzymes; Metabolic Networks and Pathways; Metalloproteins; Molybdenum; Molybdenum Cofactors; Multigene Family; Nitrogen Cycle; Oxidation-Reduction; Oxidoreductases; Phylogeny; Pteridines; Structure-Activity Relationship; Tungsten
PubMed: 31288391
DOI: 10.3390/ijms20133349 -
Nature Communications Sep 2019The recent decline in energy, size and complexity scaling of traditional von Neumann architecture has resurrected considerable interest in brain-inspired computing....
The recent decline in energy, size and complexity scaling of traditional von Neumann architecture has resurrected considerable interest in brain-inspired computing. Artificial neural networks (ANNs) based on emerging devices, such as memristors, achieve brain-like computing but lack energy-efficiency. Furthermore, slow learning, incremental adaptation, and false convergence are unresolved challenges for ANNs. In this article we, therefore, introduce Gaussian synapses based on heterostructures of atomically thin two-dimensional (2D) layered materials, namely molybdenum disulfide and black phosphorus field effect transistors (FETs), as a class of analog and probabilistic computational primitives for hardware implementation of statistical neural networks. We also demonstrate complete tunability of amplitude, mean and standard deviation of the Gaussian synapse via threshold engineering in dual gated molybdenum disulfide and black phosphorus FETs. Finally, we show simulation results for classification of brainwaves using Gaussian synapse based probabilistic neural networks.
Topics: Disulfides; Molybdenum; Nanotechnology; Neural Networks, Computer; Normal Distribution; Transistors, Electronic
PubMed: 31519885
DOI: 10.1038/s41467-019-12035-6 -
Chemical Reviews Jun 2020Biological nitrogen fixation is catalyzed by the enzyme nitrogenase, which facilitates the cleavage of the relatively inert triple bond of N. Nitrogenase is most... (Review)
Review
Biological nitrogen fixation is catalyzed by the enzyme nitrogenase, which facilitates the cleavage of the relatively inert triple bond of N. Nitrogenase is most commonly associated with the molybdenum-iron cofactor called FeMoco or the M-cluster, and it has been the subject of extensive structural and spectroscopic characterization over the past 60 years. In the late 1980s and early 1990s, two "alternative nitrogenase" systems were discovered, isolated, and found to incorporate V or Fe in place of Mo. These systems are regulated by separate gene clusters; however, there is a high degree of structural and functional similarity between each nitrogenase. Limited studies with the V- and Fe-nitrogenases initially demonstrated that these enzymes were analogously active as the Mo-nitrogenase, but more recent investigations have found capabilities that are unique to the alternative systems. In this review, we will discuss the reactivity, biosynthetic, and mechanistic proposals for the alternative nitrogenases as well as their electronic and structural properties in comparison to the well-characterized Mo-dependent system. Studies over the past 10 years have been particularly fruitful, though key aspects about V- and Fe-nitrogenases remain unexplored.
Topics: Models, Molecular; Molybdenum; Nitrogen; Nitrogen Fixation; Nitrogenase
PubMed: 32129988
DOI: 10.1021/acs.chemrev.9b00704 -
Sensors (Basel, Switzerland) Apr 2022Close monitoring of vital physiological parameters is often key in following the evolution of certain medical conditions (e.g., diabetes, infections, post-operative... (Review)
Review
Close monitoring of vital physiological parameters is often key in following the evolution of certain medical conditions (e.g., diabetes, infections, post-operative status or post-traumatic injury). The allocation of trained medical staff and specialized equipment is, therefore, necessary and often translates into a clinical and economic burden on modern healthcare systems. As a growing field, transient electronics may establish fully bioresorbable medical devices capable of remote real-time monitoring of therapeutically relevant parameters. These devices could alert remote medical personnel in case of any anomaly and fully disintegrate in the body without a trace. Unfortunately, the need for a multitude of biodegradable electronic components (power supplies, wires, circuitry) in addition to the electrochemical biosensing interface has halted the arrival of fully bioresorbable electronically active medical devices. In recent years molybdenum (Mo) and tungsten (W) have drawn increasing attention as promising candidates for the fabrication of both energy-powered active (e.g., transistors and integrated circuits) and passive (e.g., resistors and capacitors) biodegradable electronic components. In this review, we discuss the latest Mo and W-based dissolvable devices for potential biomedical applications and how these soluble metals could pave the way towards next-generation fully transient implantable electronic systems.
Topics: Electric Power Supplies; Electronics; Humans; Molybdenum; Prostheses and Implants; Tungsten
PubMed: 35459047
DOI: 10.3390/s22083062 -
Molecules (Basel, Switzerland) Sep 2022Formate dehydrogenases (FDH) reversibly catalyze the interconversion of CO to formate. They belong to the family of molybdenum and tungsten-dependent oxidoreductases.... (Review)
Review
Formate dehydrogenases (FDH) reversibly catalyze the interconversion of CO to formate. They belong to the family of molybdenum and tungsten-dependent oxidoreductases. For several decades, scientists have been synthesizing structural and functional model complexes inspired by these enzymes. These studies not only allow for finding certain efficient catalysts but also in some cases to better understand the functioning of the enzymes. However, FDH models for catalytic CO reduction are less studied compared to the oxygen atom transfer (OAT) reaction. Herein, we present recent results of structural and functional models of FDH.
Topics: Carbon Dioxide; Formate Dehydrogenases; Formates; Molybdenum; Oxidation-Reduction; Oxygen; Tungsten
PubMed: 36144724
DOI: 10.3390/molecules27185989 -
Metal Ions in Life Sciences Mar 2020The last 20 years have seen a dramatic increase in our mechanistic understanding of the reactions catalyzed by pyranopterin Mo and W enzymes. These enzymes possess a...
The last 20 years have seen a dramatic increase in our mechanistic understanding of the reactions catalyzed by pyranopterin Mo and W enzymes. These enzymes possess a unique cofactor (Moco) that contains a novel ligand in bioinorganic chemistry, the pyranopterin ene-1,2-dithiolate. A synopsis of Moco biosynthesis and structure is presented, along with our current understanding of the role Moco plays in enzymatic catalysis. Oxygen atom transfer (OAT) reactivity is discussed in terms of breaking strong metal-oxo bonds and the mechanism of OAT catalyzed by enzymes of the sulfite oxidase (SO) family that possess dioxo Mo(VI) active sites. OAT reactivity is also discussed in members of the dimethyl sulfoxide (DMSO) reductase family, which possess des-oxo Mo(IV) sites. Finally, we reveal what is known about hydride transfer reactivity in xanthine oxidase (XO) family enzymes and the formate dehydrogenases. The formal hydride transfer reactivity catalyzed by xanthine oxidase family enzymes is complex and cleaves substrate C-H bonds using a mechanism that is distinct from monooxygenases. The chapter primarily highlights developments in the field that have occurred since ~2000, which have contributed to our collective structural and mechanistic understanding of the three canonical pyranopterin Mo enzymes families: XO, SO, and DMSO reductase.
Topics: Biocatalysis; Molybdenum; Sulfite Oxidase; Tungsten
PubMed: 32851830
DOI: 10.1515/9783110589757-015 -
The Journal of Biological Chemistry Mar 2022Sulfite oxidase (SOX) is a homodimeric molybdoheme enzyme that oxidizes sulfite to sulfate at the molybdenum center. Following substrate oxidation, molybdenum is reduced...
Sulfite oxidase (SOX) is a homodimeric molybdoheme enzyme that oxidizes sulfite to sulfate at the molybdenum center. Following substrate oxidation, molybdenum is reduced and subsequently regenerated by two sequential electron transfers (ETs) via heme to cytochrome c. SOX harbors both metals in spatially separated domains within each subunit, suggesting that domain movement is necessary to allow intramolecular ET. To address whether one subunit in a SOX dimer is sufficient for catalysis, we produced heterodimeric SOX variants with abolished sulfite oxidation by replacing the molybdenum-coordinating and essential cysteine in the active site. To further elucidate whether electrons can bifurcate between subunits, we truncated one or both subunits by deleting the heme domain. We generated three SOX heterodimers: (i) SOX/Mo with two active molybdenum centers but one deleted heme domain, (ii) SOX/Mo_C264S with one unmodified and one inactive subunit, and (iii) SOX_C264S/Mo harboring a functional molybdenum center on one subunit and a heme domain on the other subunit. Steady-state kinetics showed 50% SOX activity for the SOX/Mo and SOX/Mo_C264S heterodimers, whereas SOX_C264S/Mo activity was reduced by two orders of magnitude. Rapid reaction kinetics monitoring revealed comparable ET rates in SOX/Mo, SOX/Mo_C264S, and SOX/SOX, whereas in SOX_C264S/Mo, ET was strongly compromised. We also combined a functional SOX Mo domain with an inactive full-length SOX R217W variant and demonstrated interdimer ET that resembled SOX_C264S/Mo activity. Collectively, our results indicate that one functional subunit in SOX is sufficient for catalysis and that electrons derived from either Mo or Mo follow this path.
Topics: Electrons; Heme; Molybdenum; Protein Domains; Sulfite Oxidase; Sulfites
PubMed: 35120924
DOI: 10.1016/j.jbc.2022.101668 -
Environmental Health and Preventive... May 2019Melanin is detectable in various sense organs including the skin in animals. It has been reported that melanin adsorbs toxic elements such as mercury, cadmium, and lead....
BACKGROUND
Melanin is detectable in various sense organs including the skin in animals. It has been reported that melanin adsorbs toxic elements such as mercury, cadmium, and lead. In this study, we investigated the adsorption of molybdenum, which is widely recognized as a toxic element, by melanin.
METHODS
Molybdenum level of the mouse skin was measured by inductively coupled plasma mass spectrometry. The pigmentation level of murine skin was digitalized as the L* value by using a reflectance spectrophotometer. An in vitro adsorption assay was performed to confirm the interaction between molybdenum and melanin.
RESULTS
Our analysis of hairless mice with different levels of skin pigmentation showed that the level of molybdenum increased with an increase in the level of skin pigmentation (L* value). Moreover, our analysis by Spearman's correlation coefficient test showed a strong correlation (r = - 0.9441, p < 0.0001) between L* value and molybdenum level. Our cell-free experiment using the Langmuir isotherm provided evidence for the adsorption of molybdenum by melanin. The maximum adsorption capacity of 1 mg of synthetic melanin for molybdenum was 131 μg in theory.
CONCLUSION
Our in vivo and in vitro results showed a new aspect of melanin as an adsorbent of molybdenum.
Topics: Adsorption; Animals; Melanins; Mice; Mice, Hairless; Mice, Transgenic; Molybdenum; Skin; Skin Pigmentation; Water Pollutants, Chemical
PubMed: 31101002
DOI: 10.1186/s12199-019-0791-y