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RAT

MoO3 Possible Ameliorative Effects of the Royal Jelly on Hepatotoxicity and Oxidative Stress Induced by Molybdenum Nanoparticles and/or Cadmium Chloride in Male Rats

The present study aimed to investigate the effect of the royal jelly RJ  on hepatotoxicity induced by molybdenum nanoparticles MoO3-NPs , cadmium chloride CdCl2  , or their combination in male rats at biochemical, inflammation, immune response, histological, and ultrastructural levels. The physicochemical properties of MoO3 -NPs have been characterized, as well as their ultrastructural organization. A rat experimental model was employed to assess the liver toxicity of MoO3 -NPs, even in combination with CdCl2 . Different cellular studies indicate divergent mechanisms, from increased reactive oxygen species production to antioxidative damage and cytoprotective activity. Seventy male rats were allocated to groups: i  control; ii  MoO3 -NPs 500 mg/kg ; iii  CdCl2  6.5 mg/kg ; iv  RJ 85 mg/kg diluted in saline ; v  MoO3 -NPs followed by RJ 30 min after the MoO3 -NPs dose ; vi  CdCl2  followed by RJ; and vii  a combination of MoO3 -NPs and CdCl2 , followed by RJ, for a total of 30 successive days. Hepatic functions, lipid profile, inflammation marker CRP , antioxidant biomarkers SOD, CAT, GPx, and MDA , and genotoxicity were examined. Histological changes, an immunological marker for caspase-3, and transmission electron microscope variations in the liver were also investigated to indicate liver status. The results showed that RJ alleviated the hepatotoxicity of MoO3 -NPs and/or CdCl2  by improving all hepatic vitality markers. In conclusion, the RJ was more potent and effective as an antioxidant over the oxidative damage induced by the combination of MoO3 -NPs and CdCl2 .

R. Z. Hamza, R. A. Al-Eisa, and N. S. El-Shenawy,Possible Ameliorative Effects of the Royal Jelly on Hepatotoxicity and Oxidative Stress Induced by Molybdenum Nanoparticles and/or Cadmium Chloride in Male Rats, Biology Basel , 2022, 11.

MoCu− CANCER Effect of Copper and Selenium Supplementation on the Level of Elements in Rats' Femurs under Neoplastic Conditions

A study was conducted to determine the effect of long-term supplementation with selenium and copper, administered at twice the level used in the standard diet of rats, on the content of selected elements in the femoral bones of healthy rats and rats with implanted LNCaP cancer cells. After an adaptation period, the animals were randomly divided into two experimental groups. The rats in the experimental group were implanted with prostate cancer cells. The rats in the control group were kept in the same conditions as those in the experimental group and fed the same diet, but without implanted cancer cells. The cancer cells LNCaP  were intraperitoneally implanted in the amount of 1 × 106 in PBS 0.4 mL  at the age of 90 days. The content of elements in the samples was determined by a quadrupole mass spectrometer with inductively coupled plasma ionization ICP-MS . In the femoral bones of rats with implanted LNCaP cells, in the case of the standard diet and the copper-enriched diet, there was a marked decreasing trend in the content of the analysed elements relative to the control rats. This may indicate slow osteolysis taking place in the bone tissue. Contrasting results were obtained for the diet enriched with selenium; there was no significant reduction in the level of these elements, and there was even an increase in the concentrations of Fe and K in the bones of rats with implanted LNCaP cells. Particularly, numerous changes in the mineral composition of the bones were generated by enriching the diet with copper. The elements that most often underwent changes losses  in the bones were cobalt, iron, manganese and molybdenum. The changes observed, most likely induced by the implantation of LNCaP cells, may indicate a disturbance of mineral homeostasis.

D. Skrajnowska, A. Jagielska, A. Ruszczyńska, J. Idkowiak, and B. Bobrowska-Korczak,Effect of Copper and Selenium Supplementation on the Level of Elements in Rats' Femurs under Neoplastic Conditions, Nutrients, 2022, 14.

           

 

MOUSE

ALLOY− Preliminary study to investigate the distribution and effects of certain metals after inhalation of welding fumes in mice

The most important welding processes used are the gas metal arc GMA  welding, the tungsten inert gas TIG  welding, and the manual metal arc MMA  welding processes. The goal of our investigation was to monitor the distribution of iron Fe , manganese Mn , calcium Ca , and magnesium Mg  in the lung, spleen, liver, and kidney of mice after inhalation exposure of different welding methods using different steel base materials. The treatment groups were the following: MMA-mild steel, MMA-molybdenum-manganese MoMn  alloy, TIG-mild steel, and TIG-stainless steel. The samples were taken 24 and 96 h after the treatments. Most importantly, it was found that the Mn concentration in the lung' samples of the MMA-mild steel and the MMA-MoMn groups was increased extremely at both sampling times and in the spleen' samples also. In the TIG groups, the rise of the Mn concentration was only considerable in the lungs and spleens at 24 h, and emerged concentration was found in the liver in 96 h samples. Histopathology demonstrated emerged siderin content in the spleens of the treated animals and in siderin filled macrophages in the lungs mostly in all treated groups. Traces of high-level glycogen retention was found in the MMA groups at both sampling times. Similar glycogen retention in TIG-Ms and TIG stainless group's liver samples and emerged number of vacuoles, especially in the hepatocytes of the TIG-stainless steel 96 h group were also found. The mentioned results raise the consequence that there is a considerable difference in the kinetics of the Mn distribution between the MMA- and the TIG-fume-treated groups. Hence, the result suggests that manganese has a particle-size-dependent toxico-kinetics property. The anomaly of the glycogen metabolism indicates the systemic effect of the welding fumes. Also, the numerous vacuoles mentioned above show a possible liver-specific adverse effect of some components of the TIG-stainless steel welding fumes.

C. Kővágó, B. Szekeres, É. Szűcs-Somlyó, K. Májlinger, Á. Jerzsele, and J. Lehel,Preliminary study to investigate the distribution and effects of certain metals after inhalation of welding fumes in mice, Environ Sci Pollut Res Int, 2022.

MOLYBDATE−CANCER Injectable hydrogel platform with biodegradable Dawson-type polyoxometalate and R848 for combinational photothermal-immunotherapy of cancer

Photothermal therapy PTT  is a powerful strategy for cancer treatment with minimal invasiveness but still limited by lack of long-term efficacy against tumor recurrence and toxicity concerns about the slow biodegradability of the PTT agents. Herein, an injectable hydrogel platform R848/POM@GG  of gellan gum co-loaded with Dawson-type {P2Mo18} polyoxometalate POM  and Toll-like receptors agonist resiquimod R848  is developed for combinational photothermal-immunotherapy of cancer. The POM-based gellan gum hydrogel POM@GG  exhibits high photothermal conversion efficiency 63.1%  at a safe power density of 0.3 W cm-2 and good photostability during five cycles. By further incorporation of R848, the obtained R848/POM@GG exerts synergetic photothermal-immunotherapy on solid tumors, giving a high tumor inhibition rate of 99.3% and negligible lung metastases in the breast cancer mice models. A strong antitumor immune system with significantly elevated TNF-α, IL-2, and IL-6 levels is activated by R848. Additionally, the POM clusters gradually degrade to nontoxic molybdate in the physiological environment. Overall, the injectable hydrogel platform of R848/POM@GG has great translational potential for localized antitumor treatments.

Y. Liu, Y. Y. Han, S. Lu, Y. Wu, J. Li, X. Sun, and J. Yan,Injectable hydrogel platform with biodegradable Dawson-type polyoxometalate and R848 for combinational photothermal-immunotherapy of cancer, Biomater Sci, 2022, 10, 1257-1266.

MOLYBDATE− CANCER Sodium molybdate inhibits the growth of ovarian cancer cells via inducing both ferroptosis and apoptosis

Ovarian cancer has the most mortality of all gynecologic malignancies. High-grade serous ovarian carcinoma HGSOC  is the most common and deadly type of ovarian cancer. Tumor recurrence occurs due to the emergence of chemotherapy resistance. Thus, searching for new therapeutic strategies is essential for the management of ovarian cancer. Deregulation of iron metabolism can be used by ovarian cancer cells to survive, proliferate and metastasize. Here we report that sodium molybdate, a soluble molybdenum Mo  compound, induces the elevation of the labile iron pool LIP  in ovarian cancer cells, correlated with the down-regulation of genes involved in extracellular matrix organization. Sodium molybdate also induces depletion of glutathione GSH  through mediating the production of nitric oxide NO . Elevation of LIP and depletion of GSH promote the ferroptosis of ovarian cancer cells. Meanwhile, nitric oxide induces mitochondrial damage through inhibiting mitochondrial aconitase activity, ATP production, and mitochondrial membrane potential, leading to apoptosis of ovarian cancer cells. In vivo study shows that sodium molybdate reduces tumor burden in nude mice. Xenografts treated with sodium molybdate are characterized by obvious iron accumulation, increased expression of the iron storage protein ferritin, and lipid peroxide product 4-hydroxynonenal. In addition, an elevated percentage of apoptotic cells is observed in xenografts treated with sodium molybdate. Taken together, these results demonstrate that sodium molybdate can induce both ferroptosis and apoptosis of ovarian cancer cells, making it a potential therapeutic candidate for ovarian cancer.

G. Mao, D. Xin, Q. Wang, and D. Lai,Sodium molybdate inhibits the growth of ovarian cancer cells via inducing both ferroptosis and apoptosis, Free Radic Biol Med, 2022, 182, 79-92.

MOLYBDATE− CANCER Precursor Heterogeneity Driven Mo-Te Nanoparticle Structural Diversification for Cancer Photo-Theranostics

Chemical reactions between homogeneous precursors are typically used to synthesize monodisperse nanoparticles with well-controlled size and morphology. It is difficult to predict the evolved nanostructures when using two heterogeneous precursors. In this study, three types of Mo-Te nanoparticles shaped like leaves, spindles, and rice grains denoted respectively as nanoleaf, nanospindle, and nanorice  were obtained from dextrose-mediated proton-coupled electron transfer reaction between the solid polyoxomolybdate POM  and the ionic tellurite anion as precursors. All produced nanoparticles had excellent optical absorption in the ultravioletUV -visibleVis -near-infraredNIR  regions, with only slight deviations among them. After confirming nanoparticles' photothermal conversion and photocatalytic activity at multiple wavelengths, the Mo-Te nanorice was tested as a potential agent for cancer treatment due to its minimum toxicity, excellent colloidal stability, and intrinsic anticancer effect. Excellent treatment efficacy and clearance were confirmed in vitro and in vivo. Due to their photoacoustic imaging capability, the injection of pristine nanoparticles could also realize phototheranostics without using additional drugs, probes, or photosensitizers.

G. Yim, S. Kang, S. Y. Chae, E. Chung, T. K. Song, J. H. Park, C. Yoon, D. H. Min, and H. Jang,Precursor Heterogeneity Driven Mo-Te Nanoparticle Structural Diversification for Cancer Photo-Theranostics, ACS Appl Mater Interfaces, 2022, 14, 9987-10000.

NANO Mo CLUSTER− CANCER Avenue to X-ray-induced photodynamic therapy of prostatic carcinoma with octahedral molybdenum cluster nanoparticles [Bu4N 2[Mo6I8OPOPh2 6]

X-Ray-induced photodynamic therapy represents a suitable modality for the treatment of various malignancies. It is based on the production of reactive oxygen species by radiosensitizing nanoparticles activated by X-rays. Hence, it allows overcoming the depth-penetration limitations of conventional photodynamic therapy and, at the same time, reducing the dose needed to eradicate cancer in the frame of radiotherapy treatment. The direct production of singlet oxygen by octahedral molybdenum cluster complexes upon X-ray irradiation is a promising avenue in order to simplify the architecture of radiosensitizing systems. One such complex was utilized to prepare water-stable nanoparticles using the solvent displacement method. The nanoparticles displayed intense red luminescence in aqueous media, efficiently quenched by oxygen to produce singlet oxygen, resulting in a substantial photodynamic effect under blue light irradiation. A robust radiosensitizing effect of the nanoparticles was demonstrated in vitro against TRAMP-C2 murine prostatic carcinoma cells at typical therapeutic X-ray doses. Injection of a suspension of the nanoparticles to a mouse model revealed the absence of acute toxicity as evidenced by the invariance of key physiological parameters. This study paves the way for the application of octahedral molybdenum cluster-based radiosensitizers in X-ray-induced photodynamic therapy and its translation to in vivo experiments.

 

M. Koncošová, M. Rumlová, R. Mikyšková, M. Reiniš, J. Zelenka, T. Ruml, K. Kirakci, and K. Lang,Avenue to X-ray-induced photodynamic therapy of prostatic carcinoma with octahedral molybdenum cluster nanoparticles, J Mater Chem B, 2022. 10, 3303-3310

MoS2− CANCER An erythrocyte membrane-camouflaged biomimetic nanoplatform for enhanced chemo-photothermal therapy of breast cancer

Nano drug delivery systems are a research hotspot in the field of tumor therapy. In this work, molybdenum disulfide MoS2  nanosheets were selected as the base material and a natural red blood cell membrane RBC membrane  was camouflaged on the nanosheets to enhance their dispersibility and tumor targeting profile. The camouflaged molybdenum disulfide nanocomposites MoS2-RBC  were successfully prepared by incubation. This nanomaterial has good stability and biocompatibility with a good immune evasion ability. MoS2 has a large specific surface area and unique layered structure, which provides favorable conditions for the loading of anticancer drugs. Adriamycin hydrochloride DOX  was used as the model drug and the drug loading capacity was 98.98%. In the tumor microenvironment, the red cell membrane modified MoS2 drug delivery system MoS2-RBC-DOX  showed obvious pH-dependent release behavior. In addition, the excellent photothermal properties of MoS2 are conducive to the release of drugs, thus improving the efficacy. According to the cell tests, MoS2-RBC had no cytotoxicity toward tumor cells, while DOX loading induced dose-dependent cytotoxicity. Furthermore, MoS2-RBC has a favorable photothermal effect, and chemotherapy combined with photothermal therapy is more effective than any single therapy. In vivo fluorescence imaging and in vivo photothermal imaging experiments confirmed the promoted accumulation of carrier materials at the tumor site after RBC membrane modification. Finally, in vivo antitumor studies showed that photothermal/chemotherapy combined with MoS2-RBC could completely inhibit tumor growth, and the body weights of mice fluctuated within the normal range without significant decrease. In summary, this MoS2-RBC drug delivery system provides a safe, rapid and effective option for future treatment of breast cancer.

J. Q. Li, R. X. Zhao, F. M. Yang, X. T. Qi, P. K. Ye, and M. Xie,An erythrocyte membrane-camouflaged biomimetic nanoplatform for enhanced chemo-photothermal therapy of breast cancer, J Mater Chem B, 2022, 10, 2047-2056.

 

DOG

MOLYBDATE- Role of molybdenum in material immunomodulation and periodontal wound healing: Targeting immunometabolism and mitochondrial function for macrophage modulation

Recently, strategies that can target the underlying mechanisms of phenotype change to modulate the macrophage immune response from the standpoint of biological science have attracted increasing attention in the field of biomaterials. In this study, we printed a molybdenum-containing bioactive glass ceramic Mo-BGC  scaffold as an immunomodulatory material. In a clinically relevant critical-size periodontal defect model, the defect-matched scaffold featured robust immunomodulatory activity, enabling long-term stable macrophage modulation and leading to enhanced regeneration of multiple periodontal tissues in canines. Further studies demonstrated that the regeneration-enhancing function of Mo-BGC scaffold was macrophage-dependent by using canines with host macrophage depletion. To investigate the role of Mo in material immunomodulation, in vitro investigations were performed and revealed that Mo-BGC powder extract, similar to MoO42- -containing medium, induced M2 polarization by enhancing the mitochondrial function of macrophages and promoted a cell metabolic shift from glycolysis toward mitochondrial oxidative phosphorylation. Our findings demonstrate for the first time an immunomodulatory role of a Mo-containing material in the dynamic cascade of wound healing. By targeting the immunometabolism and mitochondrial function of macrophages, Mo-mediated immunomodulation provides new avenues for future material design in the field of tissue engineering and regenerative medicine.

X. T. He, X. Li, M. Zhang, B. M. Tian, L. J. Sun, C. S. Bi, D. K. Deng, H. Zhou, H. L. Qu, C. Wu, and F. M. Chen,Role of molybdenum in material immunomodulation and periodontal wound healing: Targeting immunometabolism and mitochondrial function for macrophage modulation, Biomaterials, 2022, 283, 12

[Immunomodulatory Biomaterials for Tissue Repair: https://doi.org/10.1021/acs.chemrev.0c00895]

 

ANTIBACTERIAL

Bi2MoO6 Controllable synthesis of a sponge-like Z-scheme N,S-CQDs/Bi2MoO6@TiO2 film with enhanced photocatalytic and antimicrobial activity under visible/NIR light irradiation

Multifunctional photocatalytic surfaces for pollutant degradation and antimicrobial application are often in high demand, however they confront many challenges in charge transfer and light capture ability. In this work, a sponge-like N,S-CQDs/Bi2MoO6@TiO2 film was constructed via hydrothermal technique aiming to solve above problems. As a result, the ternary film showed enhanced photocatalytic efficiency under visible and near-infrared NIR light, in which 85.8% and 44.6% of ciprofloxacin CIP were degraded after 240 min irradiation with visible and NIR light, respectively. Moreover, the composite film effectively realized photocatalytic sterilization of gram-positive B. subtilis and gram-negative E. coli under visible light irradiation. The bacterial colony decreased significantly from 7.56-log to 1-log cfu/mL after adding the ternary film within 1.5 h. The enhanced photocatalytic efficiency was closely related to both introduction of surface-functional N,S-CQDs and the construction of N,S-CQDs/Bi2MoO6@TiO2 Z-scheme system, in which the transfer efficiency of photoinduced carriers and the light absorption property were significantly improved. We consider that the N,S-CQDs/Bi2MoO6@TiO2 film is promising for the degradation of refractory pollutants and antimicrobial application under visible/NIR light irradiation. The relatively convenient recycling property and excellent photocatalytic performance of the N,S-CQDs/Bi2MoO6@TiO2 film are beneficial for industrial applications.

Y. Qu, X. Li, H. Zhang, R. Huang, W. Qi, R. Su, and Z. He,Controllable synthesis of a sponge-like Z-scheme N,S-CQDs/Bi2 MoO6 @TiO2  film with enhanced photocatalytic and antimicrobial activity under visible/NIR light irradiation, J Hazard Mater, 2022, 429, 128310.

MoO3-.Healing Diabetic Ulcers with MoO3- X  Nanodots Possessing Intrinsic ROS-Scavenging and Bacteria-Killing Capacities

Diabetic ulcers DUs  appearing as chronic wounds are difficult to heal due to the oxidative stress in the wound microenvironment and their high susceptibility to bacterial infection. A routine treatment combining surgical debridement with anti-infection therapy is widely used for treating DUs in the clinic, but hardly offers a satisfying wound healing outcome. It is known that a long-term antibiotic treatment may also lead to the drug resistance of pathogens. To address these challenges, new strategies combining both reactive oxygen species ROS  scavenging and bacterial sterilization have been proposed for fighting against DUs. Following this idea, oxygen deficient molybdenum-based nanodots MoO3- X    for healing the DUs are reported. The ROS scavenging ability of MoO3- X  nanodots is investigated and the antibacterial property of the nanodots is also demonstrated. The systematic cell and animal experimental results indicate that the MoO3- X  nanodots can effectively reduce inflammation, promote epithelial cell regeneration, accelerate angiogenesis, and facilitate DUs recovery. Most importantly, they present excellent capacity to diminish infection of methicillin-resistant Staphylococcus aureus, manifesting the potent application prospect of MoO3- X  nanodots for diabetic wound therapy.

G. Duan, L. Wen, X. Sun, Z. Wei, R. Duan, J. Zeng, J. Cui, C. Liu, Z. Yu, X. Xie, and M. Gao,Healing Diabetic Ulcers with MoO3- X  Nanodots Possessing Intrinsic ROS-Scavenging and Bacteria-Killing Capacities, Small, 2022, 18, e2107137.

MoS2 Two-Dimensional Molybdenum Sulfide-Based Materials for Photo-Excited Antibacterial Application

Bacterial infections have seriously threatened human health. The abuse of natural or artificial antibiotics leads to bacterial resistance, so developing new generation of antibacterial agents and treatment methods is urgent. Two-dimensional 2D  molybdenum sulfide MoS2   has good biocompatibility, high specific surface area to facilitate surface modification and drug loading, adjustable energy band gap, and high near-infrared photothermal conversion efficiency PCE , so it is often used for antibacterial application through its photothermal or photodynamic effects. Herein, this review makes a comprehensive summarization and discussion on the fabrication processes, structural characteristics, antibacterial performance and the corresponding mechanisms of MoS2 -based materials as well as their representative antibacterial applications. In addition, the outlooks on the remaining challenges that should be addressed in the field of MoS2 are also proposed. This article is protected by copyright. All rights reserved.

F. Chen, Y. Luo, X. Liu, Y. Zheng, Y. Han, D. Yang, and S. Wu,Two-Dimensional Molybdenum Sulfide-Based Materials for Photo-Excited Antibacterial Application, Adv Healthc Mater, 2022, e2200360.

           

MoS2− Metallic phase enabling MoS2 nanosheets as an efficient sonosensitizer for photothermal-enhanced sonodynamic antibacterial therapy

Two-dimensional 2D  transition metal dichalcogenide TMD  nanosheets e.g., MoS2  with metallic phase 1T or 1T´ phase  have been proven to exhibit superior performances in various applications as compared to their semiconducting 2H-phase counterparts. However, it remains unclear how the crystal phase of 2D TMD nanosheets affects their sonodynamic property. In this work, we report the preparation of MoS2 nanosheets with different phases metallic 1T/1T´ or semiconducting 2H  and exploration of its crystal-phase effect on photothermal-enhanced sonodynamic antibacterial therapy. Interestingly, the defective 2D MoS2 nanosheets with high-percentage metallic 1T/1T´ phase denoted as M-MoS2  present much higher activity towards the ultrasound-induced generation of reactive oxygen species ROS  as compared to the semiconducting 2H-phase MoS2 nanosheets. More interestingly, owing to its metallic phase-enabled strong absorption in the near-infrared-II NIR-II  regime, the ultrasound-induced ROS generation performance of the M-MoS2 nanosheets can be further enhanced by the photothermal effect under a 1064 nm laser irradiation. Thus, after modifying with polyvinylpyrrolidone, the M-MoS2 nanosheets can be used as an efficient sonosensitizer for photothermal-enhanced sonodynamic bacterial elimination under ultrasound treatment combining with NIR-II laser irradiation. This study demonstrates that metallic MoS2 nanosheets can be used as a promising sonosensitizer for antibacterial therapy, which might be also promising for cancer therapies.

H. Chen, X. He, Z. Zhou, Z. Wu, H. Li, X. Peng, Y. Zhou, C. Tan, and J. Shen,Metallic phase enabling MoS2 nanosheets as an efficient sonosensitizer for photothermal-enhanced sonodynamic antibacterial therapy, J Nanobiotechnology, 2022, 20, 136.

           

CARBIDE− Simultaneous removal of antibiotic resistant bacteria and antibiotic resistance genes by molybdenum carbide assisted electrochemical disinfection

Considering conventional disinfection methods are not effective in simultaneously removing ARB and ARGs, a novel electrochemical disinfection ED  process assisted by molybdenum carbide Mo2C  electrodes was developed in this study. The established ED process was proved to effectively inactivate multi-resistant ARB i.e. Escherichia coli K-12 LE392 with resistance to kanamycin, ampicillin, and tetracycline  and to degrade ARGs including tetA and blaTEM  in the form of both intracellular iARGs  and extracellular ARGs eARGs  . Specifically, within 15 min treatment by the Mo2C-assisted ED under 2.0 V, a 5-log ARB removal was realized, without any ARB regrowth observed, indicating a permanent inactivation of ARB by the process. Moreover, degradation of the iARGs 0.4-log reduction of the blaTEM  and 3.1-log reduction of the tetA  and the eARGs 4.2-log reduction of the blaTEM  and 1.1-log reduction of the tetA  were achieved within 60 min, further underpinning the viability of the Mo2C-based ED. While e- , H2O2, and •O2 played leading roles in the entire process of ED, H+ and •OH contributed to bacterial inactivation in the early and late stages of ED, respectively. The reactive species induced by electrolysis posed pressure to the ARB strains, which enhanced oxidative stress response, triggered higher reactive oxygen species generation, induced membrane damage and changed cellular structure. Collectively, the Mo2C-assisted ED demonstrated in the present study represents an attractive alternative to the traditional disinfection methods in combating the spread of antibiotic resistance.

H. Fang, Y. Liu, P. Qiu, H. L. Song, T. Liu, J. Guo, and S. Zhang,Simultaneous removal of antibiotic resistant bacteria and antibiotic resistance genes by molybdenum carbide assisted electrochemical disinfection, J Hazard Mater, 2022, 432, 128733.

           

MOLYBDATE− Synergistically enhanced photothermal transition of a polyoxometalate/peptide assembly improved the antibiofilm and antibacterial activities

We successfully developed an antimicrobial assembly Mo154 /TK-14  using molybdenum-polyoxometalate and a positively charged peptide of TK-14. It was characterized and assayed using zeta-potential, dynamic light scattering DLS , and TEM measurements. The Mo154 /TK-14 assembly showed an enhanced 808 nm absorption and, therefore, improved the photothermal conversion efficiency of Mo154  30.3%  to 38.6%. Consequently, in comparison to 5 μM Mo154  without irradiation, both the biofilm formation and bacterial viability of S. aureus were 24.6% and 20.2%, respectively, for the Mo154 /TK-14 assembly; the biofilm formation and bacterial viability were further decreased to 7.7% and 4.4% under 808 nm irradiation, respectively. Therefore, the Mo154 /TK-14 assembly reflects convincing antibacterial properties compared to Mo154 . This is due to the synergistic effect between the peptide-binding enhanced 808 nm absorption and the improved PTT properties. The antimicrobial assembly offers a novel strategy for the rational design of light-responsive antibacterial materials.

Y. Wang, G. Chen, R. Liu, X. Fang, F. Li, L. Wu, and Y. Wu,Synergistically enhanced photothermal transition of a polyoxometalate/peptide assembly improved the antibiofilm and antibacterial activities, Soft Matter, 2022.

ANTIBACTERIAL

Photocatalytic performance and antibacterial mechanism of Cu/ Ag-molybdate powder material

Mo-containing semiconductors have attracted significant attention because of their unique photosensitivity, rendering superior visible-light photocatalytic activity. The current study utilizes a combination of theoretical and experimental approaches to systematically investigate the correlation between crystal structure, morphology, photocatalytic activity and stability of rod-shaped copper molybdate (Cu3Mo2O9) and layered silver molybdate nanomaterials (Ag2MoO4). At the same time, Escherichia coli (E. coli) is used, as a model gramnegative bacterium, to demonstrate antimicrobial properties of Cu3Mo2O9 and Ag2MoO4. The results reveal that as-prepared Cu3Mo2O9 and Ag2MoO4 exhibit superior antibacterial performance and excellent photocatalytic activity. Finally, the antibacterial mechanism is proposed based on experimental results, revealing that the sterilization is achieved by ion sterilization and formation of a certain amount of ROS and medium acidification. The present work enhances our understanding of the Cu/Ag-molybdate antibacterial mechanism and demonstrates the feasibility of constructing Mo-containing photocatalysts with high photocatalytic and antimicrobial activities.

Z. H. Xia, J. Min, S. X. Zhou, H. Ma, B. Zhang, and X. N. Tang,Photocatalytic performance and antibacterial mechanism of Cu/ Ag-molybdate powder material, Ceramics International, 2021, 47, 12667-12679.

Visible light-induced antibacterial effect of MoS2: Effect of the synthesis methods

Molybdenum disulfides (MoS2) has attracted much attention as an efficient catalyst for sterilization. However, the structures and preparation methods on the bactericidal effect of MoS2 were not very clear currently. In this work, MoS2 were prepared through three ways containing ultrasonic, hydrothermal, intercalation methods, and they possessed different morphologies and structures which was confirmed by XRD, Raman and UV-Vis characterizations. E. coli was inactivated to evaluate the photo-induced antibacterial properties of these MoS2 under light (18 W) condition. Results showed that the sterilization rate of the MoS2 prepared by ultrasonic (US-MoS2), hydrothermal (HY-MoS2), intercalation (IN-MoS2) method can reach 33%, 62% and 99% after 180 min of exposure, respectively. In order to figure out the factors that affected the photo-induced antibacterial properties of MoS2, the morphologies, structures and photo-catalytic properties of MoS2 prepared via different methods were compared systematically. Results showed that the IN-MoS2 had higher metal phase content, better light responsiveness and smaller size than those of US-MoS2 and HY-MoS2. Also, the IN-MoS2 had the highest photo induced antibacterial effect. The antibacterial mechanism was studied by capture agent experiment and ESR test, and the results showed that the main active substance in the photo-induced antibacterial process was electrons.

M. M. Zhang, K. Wang, S. H. Zeng, Y. Xu, W. Y. Nie, P. P. Chen, and Y. F. Zhou,Visible light-induced antibacterial effect of MoS2: Effect of the synthesis methods, Chemical Engineering Journal, 2021, 411.

Highly efficient antimicrobial agents based on sulfur-enriched, hydrophilic molybdenum disulfide nano/microparticles and coatings functionalized with palladium nanoparticles
In this research the molybdenum disulfide (MoS2)-based nano/microparticles and coatings were synthesized through a simple, one-step hydrothermal approach without any other additives. Composition, structure, and morphology of the synthesized MoS2-based materials were investigated using ultraviolet-visible spectroscopy (UV-Vis), inductively coupled plasma optical emission spectrometry (ICP-OES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and energy-dispersive Xray spectroscopy (EDX) techniques. The fabricated materials exhibited relatively small (Delta theta = 18.7 +/- 2.5 degrees) contact angle and prominent hydrophilic properties, which are attributable to sulfur-enriched MoS2 composite as evidenced by simultaneous thermal analysis (STA) coupled with mass spectrometric (MS) analysis of evolving gaseous species (TG/DTA-MS) analysis. Such nanostructures exhibit a better adhesion of biomolecules, thus facilitating the interaction between them, as confirmed by highly effective antimicrobial action. The present study examines antimicrobial properties of hydrophilic, sulfur-enriched MoS2 nano/microparticles as well as MoS2-based coatings against various humans' pathogenic bacteria such as Salmonella enterica, Pseudomonas aeruginosa, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), Micrococcus luteus, and two Candida yeast strains (C. parapsilosis, C. krusei). The MoS2-ns (40 mu g mL(-1)) showed over 90% killing efficiency against S. aureus MRSA bacteria and both Candida yeast when exposed for 24 h. Petal-like MoS2 microstructures and heterostructured MoS2/Ti and Pd/MoS2/Ti coatings also possessed high antimicrobial potential and are considered as a promising antimicrobial agent. The MoS2-induced production of intracellular reactive oxygen species (ROS) was evidenced by measuring the standard DCF dye fluorescence. (C) 2021 Elsevier Inc. All rights reserved.
R. Zalneravicius, V. Klimas, A. Paskevicius, G. Grinciene, R. Karpicz, A. Jagminas, and A. Ramanavicius,Highly efficient antimicrobial agents based on sulfur-enriched, hydrophilic molybdenum disulfide nano/microparticles and coatings functionalized with palladium nanoparticles, Journal of Colloid and Interface Science, 2021, 591, 115-128.

        

Insights into the Antimicrobial Activity of Hydrated Cobalt molybdate Doped with Copper

Molybdates are biocidal materials that can be useful in coating surfaces that are susceptible to contamination and the spread of microorganisms. The aim of this work was to investigate the effects of copper doping of hydrated cobalt molybdate, synthesized by the co-precipitation method, on its antibacterial activity and to elucidate the structural and morphological changes caused by the dopant in the material. The synthesized materials were characterized by PXRD, Fourier Transformed Infrared (FTIR), thermogravimetric analysis/differential scanning calorimetry (TG/DSC), and SEM-Energy Dispersive Spectroscopy (SEM-EDS). The antibacterial response of the materials was verified using the Minimum Inhibitory Concentration (MIC) employing the broth microdilution method. The size of the CoMoO4 center dot 1.03H2O microparticles gradually increased as the percentage of copper increased, decreasing the energy that is needed to promote the transition from the hydrated to the beta phase and changing the color of material. CoMoO4 center dot 1.03H2O obtained better bactericidal performance against the tested strains of Staphylococcus aureus (gram-positive) than Escherichia coli (gram-negative). However, an interesting point was that the use of copper as a doping agent for hydrated cobalt molybdate caused an increase of MIC value in the presence of E. coli and S. aureus strains. The study demonstrates the need for caution in the use of copper as a doping material in biocidal matrices, such as cobalt molybdate.

L. A. L. Silva, A. A. L. Silva, M. A. S. Rios, M. P. Brito, A. R. Araujo, D. A. Silva, R. R. Pena-Garcia, E. C. Silva, J. L. Magalhaes, J. M. E. Matos, J. A. Osajima, and E. R. Triboni,Insights into the Antimicrobial Activity of Hydrated Cobaltmolybdate Doped with Copper, Molecules, 2021, 26.

   

Synergetic Lipid Extraction with Oxidative Damage Amplifies Cell-Membrane-Destructive Stresses and Enables Rapid Sterilization

Here, we introduce an innovative "poison arrowhead" approach for disinfection based on a nanosheet bacterial inactivation system that acts synergistically to achieve sterilization rates of >99.99 % (Escherichia coli) over an ultrashort time period (≈0.5 min). The two-dimensional MoS2 "arrowhead" configuration has a sharp edge structure that enables the vigorous extraction of lipids from cell membranes and subsequent membrane disruptions. In the presence of permonosulfate, a strong oxidant, sulfur vacancies containing MoS2 activate the stable molecules, which in turn produce reactive oxygen species (ROS) from edge sites to basal areas. This process not only scavenges some portion of the phospholipids to allow for MoS2 surface refreshment but also directly attacks proteins thereby inflicting further damage to injured cells and amplifying the cell-membrane-destructive stresses toward pathogenic microorganisms. With small amounts of the new material, we successfully disinfected natural water (≈99.93 % inactivation in terms of total bacteria) within 30 s.

Y. Chen, Q. Ji, G. Zhang, H. Liu, and J. Qu,Synergetic Lipid Extraction with Oxidative Damage Amplifies Cell-Membrane-Destructive Stresses and Enables Rapid Sterilization, Angew Chem Int Ed Engl, 2021, 60, 7744-7751.

 

Highly efficient antimicrobial agents based on sulfur-enriched, hydrophilic molybdenum disulfide nano/microparticles and coatings functionalized with palladium nanoparticles

In this research the molybdenum disulfide (T. H. Herdt, L. Wisnieski, and J. Buchweitz,Random-effects linear model application to herd-level assessment of bovine hepatic trace mineral concentrations, J Vet Diagn Invest, 2021, 33, 469-478. MoS2-based nano/microparticles and coatings were synthesized through a simple, one-step hydrothermal approach without any other additives. Composition, structure, and morphology of the synthesized MoS2-based materials were investigated using ultraviolet-visible spectroscopy (UV-Vis), inductively coupled plasma optical emission spectrometry (ICP-OES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX) techniques. The fabricated materials exhibited relatively small (Δθ = 18.7 ± 2.5⁰) contact angle and prominent hydrophilic properties, which are attributable to sulfur-enriched MoS2composite as evidenced by simultaneous thermal analysis (STA) coupled with mass spectrometric (MS) analysis of evolving gaseous species (TG/DTA-MS) analysis. Such nanostructures exhibit a better adhesion of biomolecules, thus facilitating the interaction between them, as confirmed by highly effective antimicrobial action. The present study examines antimicrobial properties of hydrophilic, sulfur-enriched MoS2 nano/microparticles as well as MoS2-based coatings against various humans' pathogenic bacteria such as Salmonella enterica, Pseudomonas aeruginosa, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), Micrococcus luteus, and two Candida yeast strains (C. parapsilosis, C. krusei). The MoS2-ns (40 μg mL(-1)) showed over 90% killing efficiency against S. aureus MRSA bacteria and both Candida yeast when exposed for 24 h. Petal-like MoS2 microstructures and heterostructured MoS2/Ti and Pd/ MoS2/Ti coatings also possessed high antimicrobial potential and are considered as a promising antimicrobial agent. The MoS2-induced production of intracellular reactive oxygen species (ROS) was evidenced by measuring the standard DCF dye fluorescence.

R. Žalnėravičius, V. Klimas, A. Paškevičius, G. Grincienė, R. Karpicz, A. Jagminas, and A. Ramanavičius,Highly efficient antimicrobial agents based on sulfur-enriched, hydrophilic molybdenum disulfide nano/microparticles and coatings functionalized with palladium nanoparticles, J Colloid Interface Sci, 2021, 591, 115-128.

           

       

   

           

Photodynamic chitosan functionalized MoS2 nanocomposite with enhanced and broad-spectrum antibacterial activity

Bacterial infection accompanied by antibiotic resistance leads to the lack of effective antibacterial agents, which has become an imminent problem afflicting people. Therefore, development of highly effective and broadspectrum disinfecting alternatives to tackle this challenge is of great necessity. In view of the different cell wall structures of bacteria, we designed photodynamic antibacterial system based on chlorin e6 (Ce6 loaded chitosan functionalized molybdenum sulfide (MoS2 nanocomposites (M-CS-Ce6. The nanocomposite can not only allow Ce6 to enter the cells of Gram-positive bacteria, but also destroy the cell wall permeability of Gramnegative bacteria and enhance the photo-antibacterial effect. 10 mu g/mL of M-CS-Ce6 irradiated by 660 nm laser for 5 min, completely killed the target pathogens, exhibiting significantly enhanced photo-antibacterial performance against both Gram-positive and Gram-negative bacteria. Compared with other cationic photodynamic composites, M-CS-Ce6 had stronger and broad-spectrum photo-antibacterial effect. Taken together, M-CS-Ce6 could be a promising and safe broad-spectrum antibacterial agent.

W. B. Cao, L. Yue, Y. Zhang, and Z. P. Wang,Photodynamic chitosan functionalized MoS2 nanocomposite with enhanced and broad-spectrum antibacterial activity, Carbohydrate Polymers, 2022, 277.

             

Inactivation of antibiotic resistant bacterium Escherichia coli by electrochemical disinfection on molybdenum carbide electrode

Antibiotic-resistant bacteria (ARB pose a substantial threat to public health worldwide. Electrochemistry, as a low energy consumption and environmentally friendly technique, is ideal for inactivating ARB. This study explored the utility of electrochemical disinfection (ED for inactivating ARB (Escherichia coli K-12 LE392 resistant to kanamycin, tetracycline, and ampicillin and the regrowth potential of the treated ARB. The results revealed that 5.12-log ARB removal was achieved within 30 min of applying molybdenum carbide as the anode and cathode material under a voltage of 2.0 V. No ARB regrowth was observed in the cathode chamber after 60 min of incubation in unselective broth, demonstrating that the process in the cathode chamber was more effective for permanent inactivation of ARB. The mechanisms underlying the ARB inactivation were verified based on intercellular reactive oxygen species (ROS measurement, membrane integrity detection, and genetic damage assessment. Higher ROS production and membrane permeability were observed in the cathode and anode groups (p < 0.001 compared to the control group (0 V. In addition, the DNA was more likely to be damaged during the ED process. Collectively, our results demonstrate that ED is a promising technology for disinfecting water to prevent the spread of ARB.

Y. Liu, S. Zhang, H. Fang, Q. Wang, S. Jiang, C. Zhang, and P. Qiu,Inactivation of antibiotic resistant bacterium Escherichia coli by electrochemical disinfection on molybdenum carbide electrode, Chemosphere, 2022, 287, 132398.

             

In situ grown bacterial cellulose/MoS2 composites for multi-contaminant wastewater treatment and bacteria inactivation

For the purpose of developing multifunctional water purification materials capable of degrading organic pollutants while simultaneously inactivating microorganisms from contaminated wastewater streams, we report here a facile and eco-friendly method to immobilize molybdenum disulfide into bacterial cellulose via a one-step in-situ biosynthetic method. The resultant nanocomposite, termed BC/MoS2, was shown to possess a photocatalytic activity capable of generating ·OH from H2O2, while also exhibiting photodynamic/photothermal mechanisms, the combination of which exhibits synergistic activity for the degradation of pollutants as well as for bacterial inactivation. In the presence of H2O2, the BC/MoS2 nanocomposite exhibited excellent antibacterial efficacy upwards of 99.9999% (6 log units for the photoinactivation of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus upon infrared (IR lamp illumination (100 W, 760 nm < lambda < 5000 nm, 15 cm vertical distance; 5 min. Mechanistic studies revealed synergistic pathogen inactivation resulting from the combination of photocatalytically generated ·OH and hyperthermia induced by the photothermal conversion of the near-IR light. In addition, the BC/MoS2 nanocomposite also showed excellent photodegradation activity for common aqueous contaminants in the presence of H2O2, including malachite green (a textile dye, catechol violet (a phenol and formaldehyde. Taken together, our findings demonstrate that sustainable materials such as BC/ MoS2 have potential applications in wastewater treatment and microorganism disinfection.

H. Y. Shen, S. Q. Liao, C. Y. Jiang, J. W. Zhang, Q. F. Wei, R. A. Ghiladi, and Q. Q. Wang,In situ grown bacterial cellulose/MoS2 composites for multi-contaminant wastewater treatment and bacteria inactivation, Carbohydrate Polymers, 2022, 277.

             

Modulation of bovine serum albumin aggregation by glutathione functionalized MoS2 quantum dots

In present study, a novel glutathione functionalized MoS2 quantum dots (GSH-MoS2 QDs was synthesized from sodium molybdate dihydrate and glutathione by using a one-pot hydrothermal method. After they were characterized, the influence of GSH-MoS2 QDs on amyloid aggregation of bovine serum albumin (BSA was investigated by various analytical methods including thioflavin T fluorescence assay, circular dichroism and transmission electron microscope. Moreover, the effect of GSH-MoS2 QDs on cytotoxicity induced by BSA amyloid fibrils and cell penetration were evaluated by MTT assay and confocal fluorescence imaging, respectively. The results indicated that the GSH-MoS2 QDs not only had good water solubility, excellent biocompatibility and low cytotoxicity, but also could obviously inhibit the aggregation of BSA and depolymerize the formed BSA aggregates. The data obtained from this work demonstrated that the GSH-MoS2 QDs is expected to become a candidate drug for the treatment of amyloid-related diseases.

H. J. Zeng, L. J. Sun, L. B. Qu, and R. Yang,Modulation of bovine serum albumin aggregation by glutathione functionalized MoS2 quantum dots, International Journal of Biological Macromolecules, 2022, 195, 237-245.

 

 Reusable MoS2-Modified Antibacterial Fabrics with Photothermal Disinfection Properties for Repurposing of Personal Protective Masks

The current pandemic caused by SARS-CoV-2 has seen a widespread use of personal protective equipment, especially face masks. This has created the need to develop better and reusable protective masks with built-in antimicrobial, self-cleaning, and aerosol filtration properties to prevent the transmission of air-borne pathogens such as the coronaviruses. Herein, molybdenum disulfide (MoS2) nanosheets are used to prepare modified polycotton fabrics having excellent antibacterial activity and photothermal properties. Upon sunlight irradiation, the nanosheet-modified fabrics rapidly increased the surface temperature to similar to 77 degrees C, making them ideal for sunlight-mediated self-disinfection. Complete self-disinfection of the nanosheet-modified fabric was achieved within 3 min of irradiation, making the fabrics favorably reusable upon self-disinfection. The nanosheet-modified fabrics maintained the antibacterial efficiency even after 60 washing cycles. Furthermore, the particle filtration efficiency of three-layered surgical masks was found to be significantly improved through incorporation of the MoS2-modified fabric as an additional layer of protective clothing, without compromising the breathability of the masks. The repurposed surgical masks could filter out around 97% of 200 nm particles and 96% of 100 nm particles, thus making them potentially useful for preventing the spread of coronaviruses (120 nm) by trapping them along with antibacterial protection against other airborne pathogens.

P. Kumar, S. Roy, A. Sarkar, and A. Jaiswal,Reusable MoS2-Modified Antibacterial Fabrics with Photothermal Disinfection Properties for Repurposing of Personal Protective Masks, Acs Applied Materials & Interfaces, 2021, 13, 12912-12927.

 

           

           

ANTIBACTERIAL ANTIVIRAL

Polymer Blend Containing MoO3 Nanowires with Antibacterial Activity against Staphylococcus epidermidis ATCC 12228

Antibacterial activity of a polymer nanocomposite containing water-soluble poly(ethylene oxide) (PEO), water insoluble poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), and MoO3 nanowires or MoO3 microparticles as antibacterial active substances is reported. The UV-vis absorption method was used for the illumination of dissolving of the MoO3 particles of different size and morphology in water. Dissolving of MoO3 nanowires (1 mg ml(-1)) decreases pH bellow 3.6 in only 3 min and below 3 in 15 min, while dissolving of the PEO/PVDF-HFP/MoO3 nanowires coating (5 mg ml(-1)) decreases pH bellow 3.6 in 90 min. These coatings completely destroy the Staphylococcus epidermidis ATCC 12228 bacterial strain within 3 h. The proposed applications are antibacterial protective coatings of contact surfaces.

U. G. Centa, P. Kocbek, 2A. Belcarz, S. D. Skapin, and M. Remskar,Polymer Blend Containing MoO3 Nanowires with Antibacterial Activity against Staphylococcus epidermidis ATCC 12228, Journal of Nanomaterials, 2020, |Article ID 9754024 | https://doi.org/10.1155/2020/9754024.

Effects of cerium and tungsten substitution on antiviral and antibacterial properties of lanthanum molybdate

Powders of cerium (Ce)-substituted and tungsten (W)-substituted La2Mo2O9 (LMO) were prepared using polymerizable complex method. Their antiviral and antibacterial performances were then evaluated using bacteriophage Qβ, bacteriophage Φ6, Escherichia coli, and Staphylococcus aureus. The obtained powders, which were almost single-phase, exhibited both antiviral and antibacterial properties. Effects of dissolved ions on their antiviral activity against bacteriophage Qβ were remarkable. A certain contribution of direct contact to the powder surface was also inferred along with the dissolved ion effect for antiviral activity against bacteriophage Φ6. Dissolved ion effects and pH values suggest that both Mo and W are in the form of polyacids. Antiviral activity against bacteriophage Φ6 was improved by substituting Ce for La in LMO. Similarly to LMO, Ce-substituted LMO exhibited hydrophobicity. Inactivation of alkaline phosphatase enzyme proteins was inferred as one mechanism of the antiviral and antibacterial activities of the obtained powders.

T. Matsumoto, K. Sunada, T. Nagai, T. Isobe, S. Matsushita, H. Ishiguro, and A. Nakajima,Effects of cerium and tungsten substitution on antiviral and antibacterial properties of lanthanum molybdate, Mater Sci Eng C Mater Biol Appl, 2020, 117, 111323.

             

Synergistic antibacterial activity of streptomycin sulfate loaded PEG-MoS2/rGO nanoflakes assisted with near-infrared

Synergistic antibacterial strategies have received growing attention due to their significantly enhanced antibacterial activity. Herein, we demonstrated a synergistic antibacterial strategy based on streptomycin sulfate (SS) loaded polyethylene glycol-MoS2/reduced graphene oxide (PEG-MoS2/rGO) nanoflakes assisted with near-infrared (NIR). The nanoflakes of PEG-MoS2/rGO were ultrasonically exfoliated well from the nanoflowers of PEG-MoS2/rGO fabricated by hydrothermal method, which was of antibacterial activity against Staphylococcus aureus and Escherichia coli after loading of SS. Under the irradiation of NIR, the antibacterial activity was significantly enhanced by the synergistic effects of physical damage, protein synthesis inhibition, thermal injury and oxidative stress. Moreover, the cytotoxicity of the nanoflakes was very low. The results suggest the great potential of PEG-MoS2/rGO-SS as a photothermal antibacterial agent.

X. Zhao, M. Chen, H. Wang, L. Xia, M. Guo, S. Jiang, Q. Wang, X. Li, and X. Yang,Synergistic antibacterial activity of streptomycin sulfate loaded PEG-MoS2/rGO nanoflakes assisted with near-infrared, Materials science & engineering. C, Materials for biological applications, 2020, 116, 111221.

             

Near-Infrared Regulated Nanozymatic/Photothermal/Photodynamic Triple-Therapy for Combating Multidrug-Resistant Bacterial Infections via Oxygen-Vacancy Molybdenum Trioxide Nanodots

Bacterial infections have become a major danger to public health because of the appearance of the antibiotic resistance. The synergistic combination of multiple therapies should be more effective compared with the respective one alone, but has been rarely demonstrated in combating bacterial infections till now. Herein, oxygen-vacancy molybdenum trioxide nanodots (MoO3–x NDs) are proposed as an efficient and safe bacteriostatic. The MoO3–x NDs alone possess triple-therapy synergistic efficiency based on the single near-infrared irradiation (808 nm) regulated combination of photodynamic, photothermal, and peroxidase-like enzymatic activities. Therein, photodynamic and photothermal therapies can be both achieved under the excitation of a single wavelength light source (808 nm). Both the photodynamic and nanozyme activity can result in the generation of reactive oxygen species (ROS) to reach the broad-spectrum sterilization. Interestingly, the photothermal effect can regulate the MoO3–x NDs to their optimum enzymatic temperature (50 °C) to give sufficient ROS generation in low concentration of H2O2 (100 µm). The MoO3–xNDs show excellent antibacterial efficiency against drug-resistance extended spectrum β-lactamases producing Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA). Animal experiments further indicate that the MoO3–x NDs can effectively treat wounds infected with MRSA in living systems.

Y. Zhang, D. Li, J. Tan, Z. Chang, X. Liu, W. Ma, and Y. Xu,Near-Infrared Regulated Nanozymatic/Photothermal/Photodynamic Triple-Therapy for Combating Multidrug-Resistant Bacterial Infections via Oxygen-Vacancy Molybdenum Trioxide Nanodots, Small, 2020, e2005739.

             

MoO3 ANTIBACTERIAL

In-vitro toxicity of molybdenum trioxide nanoparticles on human keratinocytes

Molybdenum trioxide (MoO3) nanoparticles (NPs) embedded in polymer films have been proposed as a cheap way of producing antibacterial coatings on external surfaces. Recently, we synthesized MoO3 nanowires in a unique shape and degree of anisotropy, which enables their fast water dissolution and quick antimicrobial reaction. Potential human health risks following the exposure to MoO3 NPs however need to be assessed prior their wide use. We therefore, investigated the biological effect of these newly synthesized MoO3 NPs on the human keratinocyte cell line HaCaT, used here as a model for the human skin. Exposure of HaCaT cells to 1 mg/mL MoO3 NPs concentration for 1 h showed no effect on cell survival, had no influence on reactive oxygen species production, expression of proteins involved in antioxidant defense, secretion of pro-inflammatory cytokines, nor induced DNA damage. Interestingly however, ERK and p38 MAP kinases were activated, and upon longer time exposure, induced a moderate release of the pro-inflammatory cytokine interleukin 6, increased DNA damage and increased the level of caspase independent cell death. Our study indicates that exposing HaCaT cells to antibacterial MoO3 NPs water-based solution in durations less than 1 h exhibits no cytotoxicity, but rather triggers cell signalling involved in cell survival and inflammation; which should be taken into consideration when evaluating MoO3 NPs for medical applications.

K. Božinović, D. Nestić, U. G. Centa, A. Ambriović-Ristov, A. Dekanić, L. de Bisschop, M. Remškar, and D. Majhen,In-vitro toxicity of molybdenum trioxide nanoparticles on human keratinocytes, Toxicology, 2020, 444, 152564.

 

ANIMALS

Some toxic metals (Al, As, Mo, Hg) from cow's milk raised in a possibly contaminated area by different sources

Milk can be considered as an indicator of the degree of environmental contamination of the place where it is produced and this is especially important when assessing its content in toxic metals. Therefore, 36 bovine milk samples from 7 farms with a semi-extensive grazing system were analysed, located in Asturias (Spain), in an area with high probability of being highly contaminated due to a mining zone, with important industrial activity and near high-density highway traffic. The samples were lyophilised to achieve total dehydration, further analysed using inductively coupled plasma mass spectrometry (ICP-MS). The metals titrated were aluminium (Al), arsenic (As), moybdenum (Mo) and mercury (Hg) in the lyophilised samples and subsequently extrapolated their values to whole milk. All samples analysed showed levels of Al and Mo above the limit of detection, with mean values of Al of 140.89 +/- 157.07 in liquid milk and 1065.76 +/- 1073.45 in lyophilised milk and Mo of 20.72 +/- 14.61 mug/kg and 152.26 +/- 96.82 mug/kg in whole and lyophilised milk. Only As was detected in four samples with mean values of 18.45 +/- 6.89 and 166.45 +/- 42.30 mug/kg in liquid and lyophilised milk, respectively, and no Hg was found in any of them. In no case do the values found indicate a significant hazard to the population and are in agreement with those found in other investigations. Although the various anthropogenic activities of the area (industrial, mining, traffic density) could, a priori, indicate a possibly contaminated area.

J. R. Gonzalez-Montana, E. Senis, A. J. Alonso, M. E. Alonso, M. P. Alonso, and J. C. Dominguez,Some toxic metals (Al, As, Mo, Hg) from cow's milk raised in a possibly contaminated area by different sources, Environmental science and pollution research international, 2019, 26, 28909-28918.

               

In vivo assessment of moybdenum and cadmium co-induced the mRNA levels of heat shock proteins, inflammatory cytokines and apoptosis in shaoxing duck (Anas platyrhyncha) testicles

Cadmium (Cd) and high dietary intake of moybdenum (Mo) can lead to adverse reactions on animals, but the combined impacts of Mo and Cd on testicle are not clear. To investigate the co-induced toxic effects of Mo and Cd in duck testicles on the mRNA levels of heat shock proteins (HSPs), inflammatory cytokines, and apoptosis. A total of sixty 11-day-old male Shaoxing ducks (Anas platyrhyncha) were randomly divided into 6 groups and testicles were collected on day 120. The mRNA levels of HSPs (HSP60, HSP70, HSP90), inflammatory cytokines (TNF-alpha, NF-kappaB, COX-2), and apoptosis genes (Bcl-2, Bak-1, Caspase-3) were determined by real-time quantitative polymerase chain reaction (RT-qPCR), meanwhile the changes of ultrastructural were evaluated. The results showed HSPs mRNA levels were increased in high Mo and Cd groups, however, they were decreased in high dose Mo and Cd co-treated group. In all treatment groups, the mRNA levels of Bak-1 and Caspase-3 were upregulated, and Bcl-2 mRNA level was downregulated, especially in combination groups. The TNF-alpha, NF-kappaB, and COX-2 expression in co-exposure groups were higher than those in single groups. Furthermore, the ultrastructural changes showed nuclear deformation, mitochondria hyperplasia and cristaes rupture, and vacuolation in combination groups. Changes of all above factors indicated a possible synergistic relationship between the two elements, and the high expression of HSPs and inflammatory cytokines may play a role in the resistance of testicles toxicity induced by Mo or Cd or both.

X. Dai, G. Nie, H. Cao, C. Xing, G. Hu, and C. Zhang,In vivo assessment of moybdenum and cadmium co-induced the mRNA levels of heat shock proteins, inflammatory cytokines and apoptosis in shaoxing duck (Anas platyrhyncha) testicles, Poultry science, 2019, 98, 5424-5431.

Adsorption toward Cu(II) and inhibitory effect on bacterial growth occurring on molybdenum disulfide-montmorillonite hydrogel surface

Novel molybdenum disulfide-montmorillonite (MoS2)@2DMMT) hydrogels for Cu(II) removal and inhibition on bacterial growth were successfully prepared.MoS2 was first in-situ growth onto 2DMMT platelet through hydrothermal method and then cross-linked with organic reagents to form hydrogels. The flower-like structure of synthesizedMoS2 could be clearly observed inMoS2@2DMMT by SEM. The synthesized hydrogels possessed a three-dimensional macroporous structure, offering a free access for contaminants to get inside and combine with the active sites. Adsorption tests revealed that efficient Cu(II) removal (65.75 mg/g) could be achieved within a short time (30 min) at pH 5. The pseudo-second-order kinetics model and Langmuir isotherm model indicated the existence of chemisorption and monolayer absorption for Cu(II) ontoMoS2@2DMMT hydrogels. Characterizations of EDS and XPS indicated that Cu(II) reacted with groups of carboxyl, hydroxyl and amidogen. Bacteriostatic tests revealed that almost a complete bacteriostatic was achieved with just small dosage (0.8 mg/mL) ofMoS2@2DMMT hydrogels after the Cu(II) removal under the normal illumination. The mechanism was ascribed to the destructive effect of Cu(II) to the cytomembrane and the damage of reactive oxygen species (ROS) to the DNA. Such hydrogel not only provided insights for treating co-existing contaminates, but also guides for designing novel polymer materials from two-dimensional (2D) nano-materials.

W. Wang, T. Wen, H. Bai, Y. Zhao, J. Ni, L. Yang, L. Xia, and S. Song,Adsorption toward Cu(II) and inhibitory effect on bacterial growth occurring on molybdenum disulfide-montmorillonite hydrogel surface, Chemosphere, 2020, 248, 126025.

Unvealing the role of beta-Ag2MoO4 microcrystals to the improvement of antibacterial activity

Crystal morphology with different surfaces is important for improving the antibacterial activity of materials. In this experimental and theoretical study, the antibacterial activity of beta-Ag2MoO4 microcrystals against the Gram-positive bacteria, namely, methicillin-resistant Staphylococcus aureus (MRSA), and the Gram-negative bacteria, namely, Escherichia coli (E. coli), was investigated. In this study, beta-Ag2MoO4 crystals with different morphologies were synthesized by a simple co-precipitation method using three different solvents. The antimicrobial efficacy of the obtained microcrystals against both bacteria increased according to the solvent used in the following order: water < ammonia < ethanol. Supported by experimental evidence, a correlation between morphology, surface energy, and antibacterial performance was established. By using the theoretical Wulff construction, which was obtained by means of density functional calculations, the morphologies with large exposition of the (001) surface exhibited superior antibacterial activity. This study provides a low cost route for synthesizing beta-Ag2MoO4 crystals and a guideline for enhancing the biological effect of biocides on pathogenic bacteria by the morphological modulation.

C. C. De Foggi, R. C. De Oliveira, M. Assis, M. T. Fabbro, V. R. Mastelaro, C. E. Vergani, L. Gracia, J. Andres, E. Longo, and A. L. Machado,Unvealing the role of beta-Ag2MoO4 microcrystals to the improvement of antibacterial activity, Materials Science & Engineering C-Materials for Biological Applications, 2020, 111, 110765.

 

BACTERIA

BACTERIAL AND ANTIBACTERIAL

Biocompatible MoS2/PDA-RGD coating on titanium implant with antibacterial property via intrinsic ROS-independent oxidative stress and NIR irradiation

To inhibit bacterial infection in situ and improve osseointegration are essentially important for long-term survival of an orthopedic implant, in particular for infection-associating revision surgery. Herein, we fabricate a functional moybdenum disulfide (MoS2)/polydopamine (PDA)-arginine-glycine-aspartic acid (RGD) coating on titanium (Ti) implant to address above concerns simultaneously. The coating not only improved the osteogenesis of mesenchymal stem cells (MSCs), but also endowed Ti substrates with effective antibacterial ability when exposing to near-infrared (NIR) irradiation. It accelerated glutathione (GSH) oxidation via photothermal energy and induced intrinsic ROS-independent oxidative stress damage deriving from MoS2 nanosheets. The results displayed that RGD-decorated MoS2 nanosheets significantly increased the cellular osteogenic behaviors of MSCs via up-regulating osteogenesis-related genes (ALP, Runx2, Col I and OCN) in vitro. Moreover, the functionalized Ti substrates demonstrated great antibacterial efficiency of over 92.6% inhibition for S. aureus and E. coli under NIR-irradiation. Hyperthermia induced by photothermal effect accelerated the GSH consumption and ROS-independent oxidative stress destroyed the integrity of bacteria membranes, which synergistically led to protein leakage and ATP decrease. Furthermore, co-culture experiment showed that S. aureus contamination was efficiently cleaned from MoS2/PDA-RGD surface after NIR photothermal treatment, while MSCs adhered and proliferated on the MoS2/PDA-RGD surface. In an S. aureus infection model in vivo, MoS2/PDA-RGD modified Ti rods killed bacteria with an efficiency of 94.6% under NIR irradiation, without causing damage to normal tissue. More importantly, the MoS2/PDA-RGD modified Ti implants accelerated new bone formation in comparison with TNT implants in vivo.

Z. Yuan, B. Tao, Y. He, J. Liu, C. Lin, X. Shen, Y. Ding, Y. Yu, C. Mu, P. Liu, and K. Cai,Biocompatible MoS2/PDA-RGD coating on titanium implant with antibacterial property via intrinsic ROS-independent oxidative stress and NIR irradiation, Biomaterials, 2019, 217, 119290.

               

Antibacterial activity and cytotoxicity of novel silkworm-like nisin@PEGylated MoS2

Recently, moybdenum disulfide functionalized with poly-ethylene glycol (PEGylated MoS2) has been widely used as a new drug delivery vehicle in biomedical field. However, the weak antibacterial activity of PEGylated MoS2 limits its application as an antibacterial agent. In this work, a novel silkworm-like conjugate of nisin loaded PEGylated MoS2 (nisin@PEGylated MoS2) was developed for antibacterial application. The morphology and structure of PEGylated MoS2 were strongly dependent on the Mo/S molar ratio of precursors during the solvothermal process. The silkworm-like skeleton was well kept after loading with nisin. A high level of reactive oxygen species (ROS) induced by the conjugate was an important cause of bacteria death. Due to the different structure of cell membranes, the sharp edges could more easily puncture into Escherichia coli (E. coli) as compared with Staphylococcus aureus (S. aureus) and produced more intracellular ROS, which improved the antibacterial activity of nisin against E. coli. As a result, nisin@PEGylated MoS2 displayed the antibacterial activity against both gram-positive and gram-negative bacteria. Furthermore, the toxicity of the conjugate was very low. Therefore, the target conjugate of nisin@PEGylated MoS2 may have great potential application as an antibacterial agent.

P. Wang, H. Wang, X. Zhao, L. Li, M. Chen, J. Cheng, J. Liu, and X. Li,Antibacterial activity and cytotoxicity of novel silkworm-like nisin@PEGylated MoS2, Colloids and surfaces. B, Biointerfaces, 2019, 183, 110491.

Bacteria and antibacterial

MoS2 antibacterial phototherapy

Enhancing the antibacterial efficacy of low-dose gentamicin with 5 minute assistance of photothermy at 50 degrees C

Implant materials are prone to bacterial infections and cause serious consequences, while traditional antibiotic therapy has a long treatment cycle and even causes bacterial resistance. In this work, a photothermal therapy (PTT) assisted drug release system has been developed on the implant surface for in situ rapid disinfection under 808 nm light irradiation within a short time, in which gentamicin (Gent) is loaded by polyethylene glycol (PEG) modified molybdenum disulfide (MoS2) on Ti surface, and then encapsulated with chitosan (CS) (CS/Gent/PEG/MoS2-Ti). The hyperthermia produced by the coatings irradiated by 808 nm near-infrared (NIR) light can not only accelerate the local release of Gent, but also reduce the activity of bacteria, which makes it easy for these locally released drugs to enter the interior of the bacteria to inhibit the protein synthesis and destroy the cell membrane. When maintained at 50 degrees C for 5 min under NIR irradiation, this system can achieve an antibacterial efficacy of 99.93% and 99.19% against Escherichia coli and Staphylococcus aureus, respectively. By contrast, even after treatment for 120 min, only a 93.79% antibacterial ratio can be obtained for Gent alone. This is because hyperthermia produced from the coatings during irradiation can assist antibiotics in killing bacteria in a short time. Even under a low dose of 2 g mL(-1), the photothermal effect assisted gentamicin can achieve an antibacterial efficacy of 96.86% within 5 min. In vitro cell culture shows that the modified surface can facilitate cell adhesion, spreading and proliferation. The 7 day subcutaneous infection model confirms that the prepared surface system can exhibit a much faster sterilization and tissue reconstruction than the control group with light assistance. Compared with the traditional drug release system, this photothermy controlled drug-loaded implant surface system can not only provide rapid and high-efficiency in situ sterilization, but also offer long-term prevention of local bacterial infection.

M. X. Ma, X. M. Liu, L. Tan, Z. D. Cui, X. J. Yang, Y. Q. Liang, Z. Y. Li, Y. F. Zheng, K. W. K. Yeung, and S. L. Wu,Enhancing the antibacterial efficacy of low-dose gentamicin with 5 minute assistance of photothermy at 50 degrees C, Biomaterials Science, 2019, 7, 1437-1447.

 

Antibacterial Nanomaterials Review

Nanomaterials with a photothermal effect for antibacterial activities: an overview

Nanomaterials and nanotechnologies have been expected to provide innovative platforms for addressing antibacterial challenges, with potential to even deal with bacterial infections involving drug-resistance. The current review summarizes recent progress over the last 3 years in the field of antibacterial nanomaterials with a photothermal conversion effect. We classify these photothermal nanomaterials into four functional categories: carbon-based nanoconjugates of graphene derivatives or carbon nanotubes, noble metal nanomaterials mainly from gold and silver, metallic compound nanocomposites such as copper sulfide and molybdenum sulfide, and polymeric as well as other nanostructures. Different categories can be assembled with each other to enhance the photothermal effects and the antibacterial activities. The review describes their fabrication processes, unique properties, antibacterial modes, and potential healthcare applications.

J. W. Xu, K. Yao, and Z. K. Xu,Nanomaterials with a photothermal effect for antibacterial activities: an overview, Nanoscale, 2019, 11, 8680-869.

 

MoS2

ANTIBACTERIAL

High antibacterial activity of chitosan - molybdenum disulfide nanocomposite

Bacterial infections have evolved as a life-threatening problem afflicting people due to the abuse of antibiotics and emergence of drug-resistant bacteria. Thus developing novel antibacterial materials is an urgent need. Herein, chitosan-MoS2 (CS-MoS2) nanocomposite was synthesized through thiol ligand functionalization and chemical modification to achieve more efficient bactericidal activity. CS-MoS2 exhibited synergistic remarkable bactericidal capability against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E.coli), where bacterial viabilities were significantly reduced. After treatment with 10 mug/mL of CS-MoS2, 100% and 98.1% of S. aureus and E.coli cells were killed respectively. A mechanism study revealed that the positively charged CS-MoS2 could interact with cell membrane, then cause damage to the membrane and cellular constituents by generation of reactive oxygen species (ROS) and glutathione (GSH) oxidation, finally inhibit bacterial growth. The CS-MoS2 could be an attractive antibacterial agent with improved efficiency and provide more strategies for application of MoS2.

W. Cao, L. Yue, and Z. Wang,High antibacterial activity of chitosan - molybdenum disulfide nanocomposite, Carbohydrate polymers, 2019, 215, 226-234.

               

               

 

               

BACTERIA

Production of Molybdenum blue by two novel molybdate reducing bacteria belonging to the genus Raoultella isolated from Egypt and Iraq

AIM: The aim of this study was to isolate potential molybdate reducing bacteria to be used for bioremediation. METHODS AND RESULTS: Two molybdate reducing bacteria (Mo1 and MoI) were isolated from polluted soil samples from Ismailia Canal, Egypt and Sallah Elddin Governorate, Iraq respectively. The isolates exhibited dark blue colonies when grown on solid medium containing sodium molybdate which indicated the reduction of molybdate to molybdenum blue. The absorbance at 865 nm were (0.743 +/- 0.007) and (0.453 +/- 0.005) for Mo1 and MoI, respectively. The molybdenum blue produced showed characteristic absorption spectrum peak at 865 nm and a shoulder at 700 nm. The isolates were identified by 16S rRNA genes sequencing and were submitted to GenBank as Raoultella ornithinolytica strain Mo1 and Raoultella planticola strain MoI. The optimum conditions were glucose as electron donor, initial pH of 6 and incubation temperature of 30 degrees C. Scanning electron micrographs were taken for both isolates in presence and absence of molybdate source.

CONCLUSION: To the best of our knowledge this is the first recordation of molybdate reduction by Raoultella sp. isolated from Egypt and Iraq.

SIGNIFICANCE AND IMPACT OF STUDY: The isolated bacteria belonging to the Raoultella could be used in in situ bioremediation. This article is protected by copyright. All rights reserved.

A. M. Saeed, E. E. Shatoury, and R. Hadid,Production of Molybdenum blue by two novel molybdate reducing bacteria belonging to the genus Raoultella isolated from Egypt and Iraq, Journal of applied microbiology, 2019. https://doi.org/10.1111/jam.14254

ANTIBACTERIAL

The antimicrobial effect of metal substrates on far food pathogens

The development of surfaces as antimicrobial materials is important to the food industry. This study investigated the antimicrobial potential of a range of metal coated surfaces including silver, titanium, copper, iron,  molybdenum , zinc and silicon (control) against Staphylococcus aureus, Escherichia coli and Listeria monocytogenes. The leaching potential of the metals were measured by inductively coupled plasma-atomic adsorption spectroscopy and were compared to the antibacterial activity of the metals using a nitroblue tetrazolium assay and an adapted BS ISO 22196:2011 standard. Leaching into solution from the coatings alone was not related to the antimicrobial activity of the coatings. Copper and zinc showed the greatest propensity to leach from the coatings; silver, titanium, iron and  molybdenum  leached at lower rates and silicon showed no leaching. Copper demonstrated the greatest antimicrobial potential followed by silver and zinc. Titanium displayed the least antimicrobial potential, however using the standard method in humid conditions resulted in increased growth of Listeria. This study provides evidence of the efficacy of copper and silver as effective antimicrobial metal surface coatings, however use of titanium under humid conditions suggest that surfaces for use in the food industry needs to be given careful consideration before application. (C) 2018 The Authors. Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.

I. D. Akhidime, F. Saubade, P. S. Benson, J. A. Butler, S. Olivier, P. Kelly, J. Verran, and K. A. Whitehead,The antimicrobial effect of metal substrates on far food pathogens, Food and Bioproducts Processing, 2019, 113, 68-76.

 

               

Antibacterial properties and modulation analysis of antibiotic activity of NaCe( MoO4)2 microcrystals

This study reports the antibacterial properties and modulation analysis of antibiotic activity by NaCe( MoO4)2 microcrystals as well as their structural and morphological characterization. Evaluation of the antibacterial and antibiotic-modulating activity was carried out using the broth microdilution method. The Minimum Inhibitory Concentrations (MICs) of the compounds were expressed as the geometric mean of the triplicate values obtained through the use of Resazurin. Compound concentrations in the plates ranged from 512 to 0.5 mu g/mL. Regarding its direct antibacterial activity, NaCe( MoO4)2 had a MIC >= 1024 mu g/mL against all studied strains. As for its modulatory effect, it presented synergism with the antibiotic Gentamicin against the S. aureus strain and with Norfloxacin against E. coil, causing a reduction of 75% and 60%, respectively, in the antibiotic quantity required to have the same effect on the strain in study.

J. V. B.  Moura, T. S. Freitas, R. P. Cruz, R. L. S. Pereira, A. R. P. Silva, A. T. L. Santos, J. H. da Silva, C. Luz-Lima, and H. D. M. Coutinho,Antibacterial properties and modulation analysis of antibiotic activity of NaCe( MoO4)2microcrystals, Microbial Pathogenesis, 2019, 126, 258-262.

 

               

Highly efficient of  molybdenum  trioxide-cadmium titanate nanocomposites for ultraviolet light photocatalytic and antimicrobial application: Influence of reactive oxygen species

In the present work we report the enhanced UV light photocatalytic performance of cadmium titanate photo-catalyst by  MoO3 for Drug pollutant degradation. The nano photocatalyst sample was synthesized employing the Pechini-ultrasonic-hydrothermal route. Therefore, the nano photocatalyst were characterized by various analytical devices. The wide scan X-ray photoelectron spectral study confirmed the  MoO3 in the CdTiO3 matrix. The crystallite size calculated with the Debye-Scherrer equation (55.4, 57.0, 61.2 and 63.1 nm for pure CdTiO3,  MoCdTi-0,  MoCdTi-1, and  MoCdTi-2 nanocomposites, respectively). SEM micrographs revealed nanowire morphology indicated the crystalline nature of the sample. The  MoO3-CdTiO3 photocatalyst degraded the aspirin pollutant in 90 min under UV light which was higher and efficient than the pristine cadmium titanate. The enhanced photocatalytic efficiency can be attributed to the significant decrease in the band gap energy relative to the pristine cadmium titanate coupled with larger surface area morphology. The actual band gap values calculated were 2.95 to 2.66 eV ranges. The antifungal efficiency of the CdTiO3, and  MoO3-CdTiO3 was examined against Aspergillus flavus, and Trigoderma veride and their antibacterial efficiency was examined against Escherichia coli, and streptococcus pyogenes. The  MoO3-CdTiO3 with high ratio of  MoO3 has suitable to good activity compared with pure CdTiO3 and other  MoO3-CdTiO3 samples.

J. M. Zhu, M. Hosseini, A. Fakhri, S. S. Rad, T. Hadadi, and N. Nobakht,Highly efficient of  molybdenum  trioxide-cadmium titanate nanocomposites for ultraviolet light photocatalytic and antimicrobial application: Influence of reactive oxygen species, Journal of Photochemistry and Photobiology B-Biology, 2019, 191, 75-82.

 

Photogenerated Charge Carriers in  molybdenum  Disulfide Quantum Dots with Enhanced Antibacterial Activity

Molybdenum  disulfide ( MoS2) nanosheets have received considerable interest due to their superior physicochemical performances to graphene nanosheets. As the lateral size and layer thickness decrease, the formed  MoS2 quantum dots (QDs) show more promise as photocatalysts, endowing them with potential antimicrobial properties under environmental conditions. However, studies on the antibacterial photodynamic therapy of  MoS2 QDs have rarely been reported. Here, we show that  MoS2 QDs more effectively promote the creation and separation of electron-hole pair than  MoS2 nanosheets, resulting in the formation of multiple reactive oxygen species (ROS) under simulated solar light irradiation. As a result, photoexcited  MoS2 QDs show remarkably enhanced antibacterial activity, and the ROS-mediated oxidative stress plays a dominant role in the antibacterial mechanism. The in vivo experiments showed that  MoS2 QDs are efficacious in wound healing under simulated solar light irradiation and exert protective effects on normal tissues, suggesting good biocompatibility properties. Our findings provide a full description of the photochemical behavior of  MoS2 QDs and the resulting antibacterial activity, which might advance the development of  MoS2-based nanomaterials as photodynamic antibacterial agents under environmental conditions.

X. Tian, Y. Sun, S. Fan, M. D. Boudreau, C. Chen, C. Ge, and J. J. Yin,Photogenerated Charge Carriers in  molybdenum  Disulfide Quantum Dots with Enhanced Antibacterial Activity, ACS Appl Mater Interfaces, 2019, 11, 4858-4866.

antibacterial activity

               

Bacteria

BACTERIA

Cyanobacteria

Impact of ageing on the fate of molybdate-zerovalent iron nanohybrid and its subsequent effect on cyanobacteria (microcystis aeruginosa) growth in aqueous media

Nanoscale zerovalent iron (nZVI) has been proposed to remediate heavy metal ions in the subsurface. However, the fate of metal-nZVI hybrid has not been fully investigated. In this study, we investigated (1) the long-term removal performance of nZVI for molybdate (Mo(VI)); (2) the relationship between the ageing of Mo-nZVI hybrid in specific solution chemistries and the remobilization of Mo(VI) from the hybrid; and (3) the effects of Mo-nZVI hybrid on cyanobacteria (Microcystis aeruginosa). Results showed that although common ions have limited influence on the removal ratio of Mo(VI) by nZVI, they do impact the structure evolution and transformation of the Mo-nZVI nanohybrid formed thereafter. Ageing time was crucial for the chemical stabilization of Mo-nZVI hybrid, but common groundwater ions retarded the stabilizing process, which may lead to a significant remobilization of Mo(VI) from the hybrid after exposure to water bodies. While low levels of Mo(VI) ions could stimulate the growth of M. aeruginosa, aged Mo-nZVI hybrid inhibited the growth of M. aeruginosa, except when ageing occurred in the presence of HPO42-/CO32- (which also retarded hybrid stabilization). This study shows that nZVI can immobilize Mo(VI) ions in groundwater, and the derived metal-nZVI hybrid can effectively suppress the potential growth of M. aeruginosa in river water.

Y. Su, D. Qian, A. S. Adeleye, J. Zhang, X. Zhou, D. Jassby, and Y. Zhang, Impact of ageing on the fate of molybdate-zerovalent iron nanohybrid and its subsequent effect on cyanobacteria (microcystis aeruginosa) growth in aqueous media, Water Res, 2018, 140, 135-147.

 

The toxicity of molybdate to freshwater and marine organisms. III. Generating additional chronic toxicity data for the refinement of safe environmental exposure concentrations in the US and Europe

The freshwater and marine long-term ecotoxicity datasets used in the European REACH registration dossiers for molybdenum and molybdenum compounds resulted in the derivation of a HC5,50%,freshwater (38.2mgMo/L) and HC5,50%,marine (5.70mgMo/L) by means of the statistical extrapolation method. Both datasets, however, did not meet the US-EPA information requirements for deriving Final Chronic Values (FCV) that were based on chronic data. US-EPA compliance was achieved by generating chronic no-effect data for the freshwater benthic amphipod Hyalella azteca and the marine inland silverside fish Menidia beryllina, using sodium molybdate dihydrate as test substance. A 42d-EC10 of 44.6mgMo/L for reproduction was determined in a water-only exposure with H. azteca. For M. beryllina, a 37d-NOEC of 139mg mMo/L for standard length and blotted wet weight was found. Other endpoints (e.g., survival, hatching success) proved to be less sensitive. Data were added to the existing chronic toxicity datasets, together with new long-term no-effect values that were identified in open literature for brown trout Salmo trutta, the marine alga Isochrysis galbana, the marine snail Nassarius dorsatus and the marine barnacle Amphibalanus amphitrite. The updated data sets resulted in a freshwater and marine HC5,50% of 35.7 and 6.85mgMo/L, respectively. The same data sets were also used for the determination of US-EPA FCVs, where the FVCfreshwater was 36.1mg/L, and the FCVmarine was 3.85mgMo/L. As the Final Plant Values for both aquatic environments were higher than their respective FCVs, the Criterion Continuous Concentration (CCC) for molybdenum is equal to the FCV.

Heijerick, D. G., and Carey, S.,The toxicity of molybdate to freshwater and marine organisms. III. Generating additional chronic toxicity data for the refinement of safe environmental exposure concentrations in the US and Europe, The Science of the total environment, 2017, 609, 420-428.

 

Precision editing of the gut microbiota ameliorates colitis

Inflammatory diseases of the gastrointestinal tract are frequently associated with dysbiosis(1-8), characterized by changes in gut microbial communities that include an expansion of facultative anaerobic bacteria of the Enterobacteriaceae family (phylum Proteobacteria). Here we show that a dysbiotic expansion of Enterobacteriaceae during gut inflammation could be prevented by tungstate treatment, which selectively inhibited molybdenum-cofactor-dependent microbial respiratory pathways that are operational only during episodes of inflammation. By contrast, we found that tungstate treatment caused minimal changes in the microbiota composition under homeostatic conditions. Notably, tungstate-mediated microbiota editing reduced the severity of intestinal inflammation in mouse models of colitis. We conclude that precision editing of the microbiota composition by tungstate treatment ameliorates the adverse effects of dysbiosis in the inflamed gut.

W. H. Zhu, M. G. Winter, M. X. Byndloss, L. Spiga, B. A. Duerkop, E. R. Hughes, L. Buttner, E. D. Romao, C. L. Behrendt, C. A. Lopez, L. Sifuentes-Dominguez, K. Huff-Hardy, R. P. Wilson, C. C. Gillis, C. Tukel, A. Y. Koh, E. Burstein, L. V. Hooper, A. J. Baumler, and S. E. Winter,Precision editing of the gut microbiota ameliorates colitis, Nature, 2018, 553, 208-+.

               

Self-Healing, antibacterial and sensing nanoparticle coating and its excellent optical applications

Self-healing, antibacterial and metal-ion sensing coatings with nanoparticles were developed using layer-by-layer (LbL) self-assembly technique via host-guest interaction. The coatings consist of MoS2 nanosheets, beta-cyclodextrin (beta-CD)-modified poly (ethylenimine) (PEI) and adamantane (AD)modified poly (acrylic acid) (PAA). Damages to conventional coatings results in cracking and affects the coatings' ability to maintain antibacterial and sensing qualities. The prepared MoS2/beta-CD-PEI/AD-PAA self-healing coatings are not only able to greatly suppress bacterial adhesion and have excellent antibacterial property, particularly under UV light irradiation, but also have a longtime service time. Moreover, the self-healing coatings first applied the fluorescence quenching for detecting heavy metals (Co2+). Fluorescence spectra demonstrated that a linear relationship existed between the fluorescence intensity and the Co2+ concentration with 0 similar to 0.1 µg/mL and the detection limit of Co2+ is 0.018 mg/mL. Therefore, the nanoparticle multilayer polyelectrolyte hybrid coatings have a potential application in food industries. (C) 2017 Elsevier B.V. All rights reserved.

H. Y. Xuan, W. Dai, Y. X. Zhu, J. Y. Ren, J. H. Zhang, and L. Q. Ge,Self-Healing, antibacterial and sensing nanoparticle coating and its excellent optical applications, Sensors and Actuators B-Chemical, 2018, 257, 1110-1117.

 

MoS2-TiO2 Nanocomposite with Excellent Adsorption Performance and High Antibacterial Activity

The need of multifunctional advanced materials, facilitating clean and sustainable environment is the key issue from the perspective of materials scientists. This study demonstrates facile and scalable synthesis of MoS2-TiO2 nanocomposites and their excellent performance as nanoadsorbents and antibacterial agent. The synthesized composites, with different loading of MoS2 and TiO2, were examined by XRD, XPS, RAMAN, FESEM and HRTEM for structural, chemical and morphological details. The MoS2-TiO2 nanocomposite displays adsorption capacity as high as 364.56mg.g(-1) for methylene blue (MB) at room temperature and the kinetic data reveal that the adsorption process of MB is well-matched with the pseudo-first-order model. The MoS2-TiO2 nanocomposites, with different morphology, have shown their capability as an organic dye scavenger with high speed and efficiency. Moreover the composites execute considerable antibacterial activity against Gram positive Staphylococcus aureus and Gram negative Escherichia coli bacteria. Thus the presented MoS2-TiO2 nanocomposite, with synergistic performance, shows huge potential in the search of multifunctional smart materials for future technology to address environment issues.

A. Pal, T. K. Jana, T. Roy, A. Pradhan, R. Maiti, S. M. Choudhury, and K. Chatterjee, MoS2-TiO2 Nanocomposite with Excellent Adsorption Performance and High Antibacterial Activity, Chemistryselect, 2018, 3, 81-90.

 

Bacteria MoS2 toxicity

Comparative toxicity of Cd, Mo, and W sulfide nanomaterials toward E-coli under UV irradiation

In this study, the phototoxicity of cadmium sulfide (CdS), molybdenum disulfide (MoS2), and tungsten disulfide (WS2) nanoparticles (NPs) toward Escherichia coil (E. coli) under UV irradiation (365 nm) was investigated. At the same mass concentration of NPs, the toxicity of three NPs decreased in the order of CdS > MoS2 > WS2. For example, the death rates of E. coil exposed to 50 mg/L CdS, MoS2, and WS2 were 96.7%, 38.5%, and 31.2%, respectively.
Transmission electron microscope and laser scanning confocal microscope images of E. coli exposed to three NPs showed the damage of cell walls and release of intracellular components. The CdS-treated cell wall was more extensively damaged than those of MoS2 treated and WS2-treated bacteria.
WS2 and MoS2 generated superoxide radical (O2.—), singlet oxygen 1O2, and hydroxyl radical under UV irradiation, CdS produced only O2- and 1O2. CdS and WS2 released ions under UV irradiation, while MoS2 did not. Reactive oxygen species (ROS) generation and toxic ion release jointly resulted in the antibacterial activities of CdS and WS2. ROS generation was the dominant toxic mechanism of MoS2 toward the bacteria. This study highlighted the importance of considering the hazardous effect of sulfide NPs after their release into natural waters under light irradiation condition. (C) 2017 Elsevier Ltd. All rights reserved.

Shang, E. X., Niu, J. F., Li, Y., Zhou, Y. J., and Crittenden, J. C.,Comparative toxicity of Cd, Mo, and W sulphide nanomaterials toward E-coli under UV irradiation, Environmental Pollution, 2017, 224, 606-614.

 

Optimization and maximization of hexavalent molybdenum reduction to Mo-blue by SERRATIA SP strain MIE2 using response surface methodology

Molybdenum has long been known to be toxic to ruminants, but not to humans. However, more recently it has been increasingly reported that molybdenum shows toxic effects to reproductive organs of fish, mouse and even humans. Hence, its removal from the environment is highly sought after. In this study, response surface methodology (RSM) was successfully applied in the optimization and maximization of Mo6+ reduction to Mo-blue by Serratia sp. MIE2 for future bioremediation application. The optimal conditions predicted by RSM were 20 mM molybdate, 3.95 mM phosphate, pH 6.25 and 25 g l-1 sucrose with absorbance of 19.53 for Mo-blue production measured at 865 nm. The validation experimental run of the predicted optimal conditions showed that the maximum Mo-blue production occurred at absorbance of 20.87, with a 6.75 % deviation from the predicted value obtained from RSM. Molybdate reduction was successfully maximized using RSM with molybdate reduction before and after optimization using RSM showing Mo-blue production starting at the absorbance value of 10.0 at 865 nm going up to an absorbance value above 20.87. The modelling kinetics of Mo6+ reduction showed that Teissier was the best model, with calculated P-max, K-s and K-i values of 1.97 Mo-blue per hour, 5.79 mM and 31.48 mM, respectively.

bin Halmi, M. I. E., Abdullah, S. R. S., Wasoh, H., Johari, W. L. W., Ali, M. S. B., Shaharuddin, N. A., and Shukor, M. Y.,Optimization and maximization of hexavalent molybdenum reduction to Mo-blue by Serratia sp strain MIE2 using response surface methodology, Rendiconti Lincei-Scienze Fisiche E Naturali, 2016, 27, 697-709.

Modelling the kinetics of hexavalent molybdenum (Mo6+) reduction by the SERRATIA sp strain MIE2 in batch culture

In the present work, the kinetics of hexavalent molybdenum reduction by the Serratia sp. strain MIE2 were investigated using several kinetic models, such as Monod, Haldane, Teissier, Aiba, Yano, Han and Leven-spiel and Luong. The statistical analysis showed that the best model was Teissier, which had the lowest RMSE and AICc values, the highest adjusted R-2 values, and an F test and with a bias factor and an accuracy factor nearest to unity (1.0). The calculated value for the Teissier constants, such as p(max), K-s and K-i, was 0.506 mu mol Mo-blue h(-1), 6.53 mM and 29.41 mM, respectively. The effect of heavy metals showed that hexavalent molybdenum reduction by the strain MIE2 was inhibited by silver, mercury and copper with a total inhibition of 96, 97, and 45 %, respectively, at a concentration of 1 ppm. Otherwise, the Mo-reducing enzyme was inhibited by mercury and zinc with an inhibition of 88 and 65 %, respectively. Most of the respiratory inhibitors did not inhibit the Mo-reducing enzyme activity, indicating that the respiratory system in this bacterium is not the site of the hexavalent molybdenum reduction. The results obtained from this study could be useful for estimating the relationship between molybdenum-blue production and the molybdate concentration, which may be important during the up scaling of the molybdenum bioremediation process.

Halmi, M. I. E., Abdullah, S. R. S., Johari, W. L. W., Ali, M. S. M., Shaharuddin, N. A., Khalid, A., and Shukor, M. Y.,Modelling the kinetics of hexavalent molybdenum (Mo6+) reduction by the Serratia sp strain MIE2 in batch culture, Rendiconti Lincei-Scienze Fisiche E Naturali, 2016, 27, 653-663.

NEGATIVE STAINING and Transmission Electron Microscopy of Bacterial Surface Structures

Negative staining is an essential and versatile staining technique in transmission electron microscopy that can be employed for visualizing bacterial cell morphology, size, and surface architecture at high resolution. Bacteria are usually transferred by passive electrostatic adsorption from suspensions in physiological saline onto suitable hydrophilic support films on electron microscopic grids. There they are contrasted, or "stained," by heavy metal ions in solution such as tungsten, uranyl, molybdate, or vanadate compounds. Here, I describe how to visualize the interaction between the bacterial M1 protein and complement factors C1q and C3 on the surface of group A streptococcus by negative staining with uranyl formate on carbon support films. The methodology should be generally applicable to the study of a large number of other bacteria-protein interactions.

Morgelin, M.,Negative Staining and Transmission Electron Microscopy of Bacterial Surface Structures, Methods in molecular biology (Clifton, N.J.), 2017, 1535, 211-217.

Investigating the Influence of MoS2 Nanosheets on E-COLI from Metabolomics Level

Molybdenum disulfide, a type of two-dimensional layered material with unique properties, has been widely used in many fields. However, an exact understanding of its toxicity remains elusive, let alone its effects on the environmental microbial community. In this study, we utilized metabolomics technology to explore the effects of different concentrations of molybdenum disulfide nanosheets on Escherichia coli for the first time. The results showed that with increasing concentration of molybdenum disulfide nanosheets, the survival rate of Escherichia coli was decreased and the release of lactic dehydrogenase was increased. At the same time, intracellular concentrations of reactive oxygen species were dramatically increased. In addition, metabolomics analysis showed that high concentrations of molybdenum disulfide nanosheets (100, 1000 mu g/mL) could significantly affect the metabolic profile of Escherichia coli, including glycine, serine and threonine metabolism, protein biosynthesis, urea cycle and pyruvate metabolism. These results will be beneficial for molybdenum disulfide toxicity assessment and further applications.

Wu, N., Yu, Y. D., Li, T., Ji, X. J., Jiang, L., Zong, J. J., and Huang, H.,Investigating the Influence of MoS2 Nanosheets on E-coli from Metabolomics Level, Plos One, 2016, 11.

 

IMOA Toxicological Testing Programme: Bacteriaa
SubstanceToxicity/ mg/l
Acute bacterial growth inhibitionAcute bacterial respiratory inhibition
EC10b3 h EC50c
Molybdenum trioxide (pure) d 820
Molybdenum trioxide (tech) d 3000
Ammonium dimolybdate 13  
Sodium molybdate 50  

Notes

a There are no EC criteria for bacterial toxicity. It is however factored into the German Water Hazard Classification. Under the German classification scheme, which takes into account fish, mammal and bacterial toxicity, the materials tested would give a maximum Water Hazard Classification of 1(weak hazard for waters).

b The EC10 is the concentration that causes a 10% reduction in turbidity. Test culture incubated with various concentrations of test substance for 18 hours. Turbidity measured by light transmission.

c The EC50 is the concentration that causes a 50% reduction in respiration. Test culture and test substance were left in contact for 30 minutes and three hours. At the end of each time period the dissolved oxygen content of the solution was measured.

d Growth inhibition is determined by the decrease in turbidity of test solution. Therefore, this method cannot be used on insolubles.

Users of the Database should be aware that inclusion of an abstract in the Database does not imply any IMOA endorsement of the accuracy or reliability of the reported data or the quality of a publication.