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  1. Dual Functions of a Hybrid Magnetic Magnesium Oxide Nanocomposite as a Fungicide and Plant Growth Promoter in Agriculture Applications
    Wee JL, Chan YS, Law MC
    ACS Appl Bio Mater, 2023 Nov 20;6(11):4972-4987.
    PMID: 37910790 DOI: 10.1021/acsabm.3c00515
    The use of nanometal oxides in nanoagronomy has garnered considerable attention due to their excellent antifungal and plant growth promotion properties. Hybrid nanometal oxides, which combine the strengths of individual nanomaterials, have emerged as a promising class of materials. In this study, nanomagnesium oxide (n-MgO) and hybrid magnetic nanomagnesium oxide (m/n-MgO) were successfully synthesized via the ultrasound-mediated sol-gel method. Characterization results, including TGA, XRD, VSM, and FTIR, confirmed the successful synthesis of m/n-MgO. Both n-MgO and m/n-MgO underwent antifungal assays and plant growth promotion ability studies, benchmarked against the conventional fungicide-copper oxychloride. This study bridges a significant gap by simultaneously reporting the antifungal properties of both n-MgO and m/n-MgO and their impact on plant growth. The disc diffusion assay suggested that the antifungal activity of n-MgO and m/n-MgO against F. oxysporum was inversely related to the particle size. Notably, n-MgO exhibited superior antifungal performance (lower minimum inhibitory concentration (MIC)) and sustained efficacy compared with m/n-MgO, owing to distinct antifungal mechanisms. Nanorod-shaped MgO, with a smaller size (8.24 ± 5.61 nm) and higher aspect ratio, allowed them to penetrate the fungal cell wall and cause intercellular damage. In contrast, cubical m/n-MgO, with a larger size (20.95 ± 9.99 nm) and lower aspect ratio, accumulate on the fungal cell wall surface, disrupting the wall integrity, albeit less effectively against F. oxysporum. Moreover, in plant growth promotion studies, m/n-MgO-treated samples exhibited a 15.7% stronger promotion effect compared to n-MgO at their respective MICs. In addition, both n-MgO and m/n-MgO outperformed copper oxychloride in terms of antifungal and plant growth promoting activities. Thus, m/n-MgO presents a promising alternative to conventional copper-based fungicides, offering dual functionality as a fungicide and plant growth promoter, while the study also delves into the antifungal mechanisms at the intracellular level, enhancing its novelty.
    Matched MeSH terms: Oxides
  2. Synthesis, mechanical properties, and in vitro biocompatibility with osteoblasts of calcium silicate-reduced graphene oxide composites
    Mehrali M, Moghaddam E, Shirazi SF, Baradaran S, Mehrali M, Latibari ST, et al.
    ACS Appl Mater Interfaces, 2014 Mar 26;6(6):3947-62.
    PMID: 24588873 DOI: 10.1021/am500845x
    Calcium silicate (CaSiO3, CS) ceramics are promising bioactive materials for bone tissue engineering, particularly for bone repair. However, the low toughness of CS limits its application in load-bearing conditions. Recent findings indicating the promising biocompatibility of graphene imply that graphene can be used as an additive to improve the mechanical properties of composites. Here, we report a simple method for the synthesis of calcium silicate/reduced graphene oxide (CS/rGO) composites using a hydrothermal approach followed by hot isostatic pressing (HIP). Adding rGO to pure CS increased the hardness of the material by ∼40%, the elastic modulus by ∼52%, and the fracture toughness by ∼123%. Different toughening mechanisms were observed including crack bridging, crack branching, crack deflection, and rGO pull-out, thus increasing the resistance to crack propagation and leading to a considerable improvement in the fracture toughness of the composites. The formation of bone-like apatite on a range of CS/rGO composites with rGO weight percentages ranging from 0 to 1.5 has been investigated in simulated body fluid (SBF). The presence of a bone-like apatite layer on the composite surface after soaking in SBF was demonstrated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The biocompatibility of the CS/rGO composites was characterized using methyl thiazole tetrazolium (MTT) assays in vitro. The cell adhesion results showed that human osteoblast cells (hFOB) can adhere to and develop on the CS/rGO composites. In addition, the proliferation rate and alkaline phosphatase (ALP) activity of cells on the CS/rGO composites were improved compared with the pure CS ceramics. These results suggest that calcium silicate/reduced graphene oxide composites are promising materials for biomedical applications.
    Matched MeSH terms: Oxides/chemistry
  3. Enhancing the Efficiency of a Dye-Sensitized Solar Cell Based on a Metal Oxide Nanocomposite Gel Polymer Electrolyte
    Saidi NM, Omar FS, Numan A, Apperley DC, Algaradah MM, Kasi R, et al.
    ACS Appl Mater Interfaces, 2019 Aug 21;11(33):30185-30196.
    PMID: 31347822 DOI: 10.1021/acsami.9b07062
    To overcome the critical limitations of liquid-electrolyte-based dye-sensitized solar cells, quasi-solid-state electrolytes have been explored as a means of addressing long-term device stability, albeit with comparatively low ionic conductivities and device performances. Although metal oxide additives have been shown to augment ionic conductivity, their propensity to aggregate into large crystalline particles upon high-heat annealing hinders their full potential in quasi-solid-state electrolytes. In this work, sonochemical processing has been successfully applied to generate fine Co3O4 nanoparticles that are highly dispersible in a PAN:P(VP-co-VAc) polymer-blended gel electrolyte, even after calcination. An optimized nanocomposite gel polymer electrolyte containing 3 wt % sonicated Co3O4 nanoparticles (PVVA-3) delivers the highest ionic conductivity (4.62 × 10-3 S cm-1) of the series. This property is accompanied by a 51% enhancement in the apparent diffusion coefficient of triiodide versus both unmodified and unsonicated electrolyte samples. The dye-sensitized solar cell based on PVVA-3 displays a power conversion efficiency of 6.46% under AM1.5 G, 100 mW cm-2. By identifying the optimal loading of sonochemically processed nanoparticles, we are able to generate a homogenous extended particle network that effectively mobilizes redox-active species through a highly amorphous host matrix. This effect is manifested in a selective 51% enhancement in photocurrent density (JSC = 16.2 mA cm-2) and a lowered barrier to N719 dye regeneration (RCT = 193 Ω) versus an unmodified solar cell. To the best of our knowledge, this work represents the highest known efficiency to date for dye-sensitized solar cells based on a sonicated Co3O4-modified gel polymer electrolyte. Sonochemical processing, when applied in this manner, has the potential to make meaningful contributions toward the ongoing mission to achieve the widespread exploitation of stable and low-cost dye-sensitized solar cells.
    Matched MeSH terms: Oxides
  4. Targeted Surface Doping with Reversible Local Environment Improves Oxygen Stability at the Electrochemical Interfaces of Nickel-Rich Cathode Materials
    Steiner JD, Cheng H, Walsh J, Zhang Y, Zydlewski B, Mu L, et al.
    ACS Appl Mater Interfaces, 2019 Oct 16;11(41):37885-37891.
    PMID: 31589393 DOI: 10.1021/acsami.9b14729
    Elemental doping represents a prominent strategy to improve interfacial chemistry in battery materials. Manipulating the dopant spatial distribution and understanding the dynamic evolution of the dopants at the atomic scale can inform better design of the doping chemistry for batteries. In this work, we create a targeted hierarchical distribution of Ti4+, a popular doping element for oxide cathode materials, in LiNi0.8Mn0.1Co0.1O2 primary particles. We apply multiscale synchrotron/electron spectroscopy and imaging techniques as well as theoretical calculations to investigate the dynamic evolution of the doping chemical environment. The Ti4+ dopant is fully incorporated into the TMO6 octahedral coordination and is targeted to be enriched at the surface. Ti4+ in the TMO6 octahedral coordination increases the TM-O bond length and reduces the covalency between (Ni, Mn, Co) and O. The excellent reversibility of Ti4+ chemical environment gives rise to superior oxygen reversibility at the cathode-electrolyte interphase and in the bulk particles, leading to improved stability in capacity, energy, and voltage. Our work directly probes the chemical environment of doping elements and helps rationalize the doping strategy for high-voltage layered cathodes.
    Matched MeSH terms: Oxides
  5. A Direct n-Butane Solid Oxide Fuel Cell Using Ba(Zr0.1Ce0.7Y0.1Yb0.1)0.9Ni0.05Ru0.05O3-δ Perovskite as the Reforming Layer
    Wang D, Wong SI, Sunarso J, Xu M, Wang W, Ran R, et al.
    ACS Appl Mater Interfaces, 2021 May 05;13(17):20105-20113.
    PMID: 33886260 DOI: 10.1021/acsami.1c02502
    Hydrocarbon-fueled solid oxide fuel cells (SOFCs) that can operate in the intermediate temperature range of 500-700 °C represent an attractive SOFC device for combined heat and power applications in the industrial market. One of the ways to realize such a device relies upon exploiting an in situ steam reforming process in the anode catalyzed by an anti-carbon coking catalyst. Here, we report a new Ni and Ru bimetal-doped perovskite catalyst, Ba(Zr0.1Ce0.7Y0.1Yb0.1)0.9Ni0.05Ru0.05O3-δ (BZCYYbNRu), with enhanced catalytic hydrogen production activity on n-butane (C4H10), which can resist carbon coking over extended operation durations. Ru in the perovskite lattice inhibits Ni precipitation from perovskite, and the high water adsorption capacity of proton conducting perovskite improves the coking resistance of BZCYYbNRu. When BZCYYbNRu is used as a steam reforming catalyst layer on a Ni-YSZ-supported anode, the single fuel cell not only achieves a higher power density of 1113 mW cm-2 at 700 °C under a 10 mL min-1 C4H10 continuous feed stream at a steam to carbon (H2O/C) ratio of 0.5 but also shows a much better operational stability for 100 h at 600 °C compared with those reported in the literature.
    Matched MeSH terms: Oxides
  6. Photoelectrical Dynamics Uplift in Perovskite Solar Cells by Atoms Thick 2D TiS2 Layer Passivation of TiO2 Nanograss Electron Transport Layer
    Alias N, Ali Umar A, Malek NAA, Liu K, Li X, Abdullah NA, et al.
    ACS Appl Mater Interfaces, 2021 Jan 20;13(2):3051-3061.
    PMID: 33410652 DOI: 10.1021/acsami.0c20137
    A deficiency in the photoelectrical dynamics at the interface due to the surface traps of the TiO2 electron transport layer (ETL) has been the critical factor for the inferiority of the power conversion efficiency (PCE) in the perovskite solar cells. Despite its excellent energy level alignment with most perovskite materials, its large density of surface defect as a result of sub lattice vacancies has been the critical hurdle for an efficient photovoltaic process in the device. Here, we report that atoms thick 2D TiS2 layer grown on the surface of a (001) faceted and single-crystalline TiO2 nanograss (NG) ETL have effectively passivated the defects, boosting the charge extractability, carrier mobility, external quantum efficiency, and the device stability. These properties allow the perovskite solar cells (PSCs) to produce a PCE as high as 18.73% with short-circuit current density (Jsc), open-circuit voltage (Voc), and fill-factor (FF) values as high as 22.04 mA/cm2, 1.13 V, and 0.752, respectively, a 3.3% improvement from the pristine TiO2-NG-based PSCs. The present approach should find an extensive application for controlling the photoelectrical dynamic deficiency in perovskite solar cells.
    Matched MeSH terms: Oxides
  7. Metal-Polydopamine Framework as an Effective Fluorescent Quencher for Highly Sensitive Detection of Hg(II) and Ag(I) Ions through Exonuclease III Activity
    Ravikumar A, Panneerselvam P, Morad N
    ACS Appl Mater Interfaces, 2018 Jun 20;10(24):20550-20558.
    PMID: 29792319 DOI: 10.1021/acsami.8b05041
    In this paper, we propose a metal-polydopamine (MPDA) framework with a specific molecular probe which appears to be the most promising approach to a strong fluorescence quencher. The MPDA framework quenching ability toward various organic fluorophore such as aminoethylcoumarin acetate, 6-carboxyfluorescein (FAM), carboxyteramethylrhodamine, and Cy5 are used to establish a fluorescent biosensor that can selectively recognize Hg2+ and Ag+ ions. The fluorescent quenching efficiency was sufficient to achieve more than 96%. The MPDA framework also exhibits different affinities with ssDNA and dsDNA. In addition, the FAM-labeled ssDNA was adsorbed onto the MPDA framework, based on their interaction with the complex formed between MPDA frameworks/ssDNA taken as a sensing platform. By taking advantage of this sensor, highly sensitive and selective determination of Hg2+ and Ag+ ions is achieved through exonuclease III signal amplification activity. The detection limits of Hg2+ and Ag+ achieved to be 1.3 and 34 pM, respectively, were compared to co-existing metal ions and graphene oxide-based sensors. Furthermore, the potential applications of this study establish the highly sensitive fluorescence detection targets in environmental and biological fields.
    Matched MeSH terms: Oxides
  8. Fulltext Electrochemical Sodiation/Desodiation into Mn3O4 Nanoparticles
    Mahamad Yusoff NF, Idris NH, Md Din MF, Majid SR, Harun NA, Rahman MM
    ACS Omega, 2020 Nov 17;5(45):29158-29167.
    PMID: 33225147 DOI: 10.1021/acsomega.0c03888
    Mn3O4 is considered to be a promising anode material for sodium-ion batteries (SIBs) because of its low cost, high capacity, and enhanced safety. However, the inferior cyclic stability of the Mn3O4 anode is a major challenge for the development of SIBs. In this study, a one-step solvothermal method was established to produce nanostructured Mn3O4 with an average particle size of 21 nm and a crystal size of 11 nm. The Mn3O4 obtained exhibits a unique architecture, consisting of small clusters composed of numerous tiny nanoparticles. The Mn3O4 material could deliver high capacity (522 mAh g-1 at 100 mA g-1), reasonable cyclic stability (158 mAh g-1 after 200 cycles), and good rate capability (73 mAh g-1 at 1000 mA g-1) even without further carbon coating, which is a common exercise for most anode materials so far. The sodium insertion/extraction was also confirmed by a reversible conversion reaction by adopting an ex situ X-ray diffraction technique. This simple, cost-effective, and environmentally friendly synthesis technique with good electrochemical performance shows that the Mn3O4 nanoparticle anode has the potential for SIB development.
    Matched MeSH terms: Oxides
  9. Fulltext Growth and Characterization of Ternary Hf x Ta y O z Films via Nitrogen-Infused Wet Oxidation
    Quah HJ, Ahmad FH, Lim WF, Hassan Z
    ACS Omega, 2020 Oct 20;5(41):26347-26356.
    PMID: 33110962 DOI: 10.1021/acsomega.0c02120
    Nitrogen-infused wet oxidation at different temperatures (400-1000 °C) was employed to transform tantalum-hafnia to hafnium-doped tantalum oxide films. High-temperature wet oxidation at 1000 °C marked an onset of crystallization occurring in the film, accompanied with the formation of an interfacial oxide due to a reaction between the inward-diffusing hydroxide ions, which were dissociated from the water molecules during wet oxidation. The existence of nitrogen has assisted in controlling the interfacial oxide formation. However, high-temperature oxidation caused a tendency for the nitrogen to desorb and form N-H complex after reacting with the hydroxide ions. Besides, the presence of N-H complex implied a decrease in the passivation at the oxide-Si interface by hydrogen. As a consequence, defect formation would happen at the interface and influence the metal-oxide-semiconductor characteristics of the samples. In comparison, tantalum-hafnia subjected to nitrogen-infused wet oxidation at 600 °C has obtained the highest dielectric constant, the largest band gap, and the lowest slow trap density.
    Matched MeSH terms: Hydroxides; Nitrogen Oxides; Oxides
  10. Fulltext Hierarchical Bimetallic AgPt Nanoferns as High-Performance Catalysts for Selective Acetone Hydrogenation to Isopropanol
    Mawarnis ER, Ali Umar A, Tomitori M, Balouch A, Nurdin M, Muzakkar MZ, et al.
    ACS Omega, 2018 Sep 30;3(9):11526-11536.
    PMID: 31459253 DOI: 10.1021/acsomega.8b01268
    A combinative effect of two or more individual material properties, such as lattice parameters and chemical properties, has been well-known to generate novel nanomaterials with special crystal growth behavior and physico-chemical performance. This paper reports unusually high catalytic performance of AgPt nanoferns in the hydrogenation reaction of acetone conversion to isopropanol, which is several orders higher compared to the performance shown by pristine Pt nanocatalysts or other metals and metal-metal oxide hybrid catalyst systems. It has been demonstrated that the combinative effect during the bimetallisation of Ag and Pt produced nanostructures with a highly anisotropic morphology, i.e., hierarchical nanofern structures, which provide high-density active sites on the catalyst surface for an efficient catalytic reaction. The extent of the effect of structural growth on the catalytic performance of hierarchical AgPt nanoferns is discussed.
    Matched MeSH terms: Oxides
  11. Fulltext Electron-phonon coupling constants of two-dimensional copper oxide-based high temperature superconductors
    R. Abd-Shukor, W.Y. Lim
    ASM Science Journal, 2013;7(1):18-22.
    MyJurnal
    The electron-phonon coupling constant of the copper oxide-based high temperature superconductors in the van Hove scenario was calculated using three known models and by employing various acoustic data. Three expressions for the transition temperature from the models were used to calculate the constants. All three models assumed a logarithmic singularity in the density of states near the Fermi surface. The calculated electron-phonon coupling constant ranged from 0.06 to 0.28. The constants increased with the transition temperature indicating a strong correlation between electron-phonon coupling and superconductivity in these materials. These values were smaller than the values estimated for the conventional three-dimensional BCS theory. The results were compared with previous reports on direct measurements of electron-phonon coupling constants in the copper oxide based superconductors.
    Matched MeSH terms: Oxides
  12. Nanostructuring Mixed-Dimensional Perovskites: A Route Toward Tunable, Efficient Photovoltaics
    Koh TM, Shanmugam V, Schlipf J, Oesinghaus L, Müller-Buschbaum P, Ramakrishnan N, et al.
    Adv Mater, 2016 May;28(19):3653-61.
    PMID: 26990287 DOI: 10.1002/adma.201506141
    2D perovskites is one of the proposed strategies to enhance the moisture resistance, since the larger organic cations can act as a natural barrier. Nevertheless, 2D perovskites hinder the charge transport in certain directions, reducing the solar cell power conversion efficiency. A nanostructured mixed-dimensionality approach is presented to overcome the charge transport limitation, obtaining power conversion efficiencies over 9%.
    Matched MeSH terms: Oxides
  13. Recent Progress on Advanced Materials for Solid-Oxide Fuel Cells Operating Below 500 °C
    Zhang Y, Knibbe R, Sunarso J, Zhong Y, Zhou W, Shao Z, et al.
    Adv Mater, 2017 Dec;29(48).
    PMID: 28628239 DOI: 10.1002/adma.201700132
    Solid-oxide fuel cells (SOFCs) are electricity generators that can convert the chemical energy in various fuels directly to the electric power with high efficiency. Recent advances in materials and related key components for SOFCs operating at ≈500 °C are summarized here, with a focus on the materials, structures, and techniques development for low-temperature SOFCs, including the analysis of most of the critical parameters affecting the electrochemical performance of the electrolyte, anode, and cathode. New strategies, such as thin-film deposition, exsolution of nanoparticles from perovskites, microwave plasma heating, and finger-like channeled electrodes, are discussed. These recent developments highlight the need for electrodes with higher activity and electrolytes with greater conductivity to generate a high electrochemical performance at lower temperatures.
    Matched MeSH terms: Oxides
  14. Nanoparticle-Hydrogel Composites: Concept, Design, and Applications of These Promising, Multi-Functional Materials
    Thoniyot P, Tan MJ, Karim AA, Young DJ, Loh XJ
    Adv Sci (Weinh), 2015 02;2(1-2):1400010.
    PMID: 27980900
    New technologies rely on the development of new materials, and these may simply be the innovative combination of known components. The structural combination of a polymer hydrogel network with a nanoparticle (metals, non-metals, metal oxides, and polymeric moieties) holds the promise of providing superior functionality to the composite material with applications in diverse fields, including catalysis, electronics, bio-sensing, drug delivery, nano-medicine, and environmental remediation. This mixing may result in a synergistic property enhancement of each component: for example, the mechanical strength of the hydrogel and concomitantly decrease aggregation of the nanoparticles. These mutual benefits and the associated potential applications have seen a surge of interest in the past decade from multi-disciplinary research groups. Recent advances in nanoparticle-hydrogel composites are herein reviewed with a focus on their synthesis, design, potential applications, and the inherent challenges accompanying these exciting materials.
    Matched MeSH terms: Oxides
  15. Fulltext Profile of The Betel/Tobacco Quid Chewers In six Malaysian Estates
    Tan, B.S., Rosman, A., Ng, K.H., Ahmad, N.
    Ann Dent, 2000;7(1):-.
    MyJurnal
    The aim of the study was to determine the characteristics and pattern of the betel/tobacco quid chewing habit in the estate Indian community. The study was conducted in 6 randomly selected estates. It involved oral mucosal examination and an interview to solicit personal data as well as history and details of oral habits. Of a total of 618 subjects studied, 19.3 % (n= 119; 89 females and 30 males) were betel !tobacco quid chewers. The youngest age of onset of betel quid chewing is 10 years. The mean frequency of chewing quid is 4.3 times/day and the mean duration of chewing is 8.1 minutes. Initiation to the habit occur at a young age and a major role is played by family and friends in initiation to the habit. Practises of adding tobacco and lime appear to have adverse effects and are associated with higher occurrences of precancer lesions in this study (p
    Matched MeSH terms: Oxides
  16. Fulltext Alkaline phosphatase activity assessment of two endodontic materials: a preliminary study
    Rajan, S., Awang, H., Pooi, A.H., Hassan, H., Devi, S.
    Ann Dent, 2008;15(1):5-10.
    MyJurnal
    Objective: An in vitro assessment of MG-63 human osteosarcoma cells' alkaline phosphatase (ALP) activity when in contact with calcium hydroxide powder (CH), paste (CHP) and grey mineral trioxide aggregate (MTA). Methods: MG-63 cells were seeded to the three selected materials for durations of 0.25, 0.5, 1, 24, 48 and 72 hours. BCIP-NBT assay was used and ALP activity quantified using ELISA reader at 410 nm. Results: The overall analysis for ALP activity indicated significant interaction between test materials and control (maintenance medium). Subsequently, the test materials were paired and analysed for initial (0.25, 0.5, 1 hour) and delayed response (24, 48 and 72 hours). During the initial response, CH exhibited an increased ALP activity compared to MTA. This interaction was not dependant on duration. The delayed response exhibited elevated ALP activity with CHP when compared to MTA and CH. The interaction of CHP was dependant on duration. Conclusion: All three materials exhibited increased ALP activity.
    Matched MeSH terms: Oxides
  17. Anti-cancer Application of Nat-ZnFe2O4 Nanoparticles on 2D Tumor Models
    Chabattula SC, Patra B, Gupta PK, Govarthanan K, Rayala SK, Chakraborty D, et al.
    Appl Biochem Biotechnol, 2024 Feb;196(2):1058-1078.
    PMID: 37318689 DOI: 10.1007/s12010-023-04582-y
    Metal/Metal Oxide nanoparticles (M/MO NPs) exhibit potential biomedical applications due to their tunable physicochemical properties. Recently, the biogenic synthesis of M/MO NPs has gained massive attention due to their economical and eco-friendly nature. In the present study, Nyctanthes arbor-tristis (Nat) flower extract-derived Zinc Ferrite NPs (Nat-ZnFe2O4 NPs) were synthesized and physicochemically characterized by FTIR, XRD, FE-SEM, DLS, and other instruments to study their crystallinity, size, shape, net charge, presence of phytocompounds on NP's surface and several other features. The average particle size of Nat-ZnFe2O4 NPs was approx. 25.87 ± 5.67 nm. XRD results showed the crystalline nature of Nat-ZnFe2O4 NPs. The net surface charge on NPs was -13.28 ± 7.18 mV. When tested on mouse fibroblasts and human RBCs, these NPs were biocompatible and hemocompatible. Later, these Nat-ZnFe2O4 NPs exhibited potent anti-neoplastic activity against pancreatic, lung, and cervical cancer cells. In addition, NPs induced apoptosis in tested cancer cells through ROS generation. These in vitro studies confirmed that Nat-ZnFe2O4 NPs could be used for cancer therapy. Moreover, further studies are recommended on ex vivo platforms for future clinical applications.
    Matched MeSH terms: Oxides
  18. Antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite against pathogenic bacteria and parasite
    Masri A, Abdelnasir S, Anwar A, Iqbal J, Numan A, Jagadish P, et al.
    Appl Microbiol Biotechnol, 2021 Apr;105(8):3315-3325.
    PMID: 33797573 DOI: 10.1007/s00253-021-11221-1
    BACKGROUND: Conducting polymer based nanocomposites are known to be effective against pathogens. Herein, we report the antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite (PPy-Co3O4-AgNPs) for the first time. Antibacterial activities were tested against multi-drug-resistant Gram-negative Escherichia coli (E. coli) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) bacteria, while antiamoebic effects were assessed against opportunistic protist Acanthamoeba castellanii (A. castellanii).

    RESULTS: The ternary nanocomposite containing conducting polymer polypyrrole, cobalt oxide, and silver nanoparticles showed potent antimicrobial effects against these pathogens. The antibacterial assay showed that PPy-Co3O4-AgNPs exhibited significant bactericidal activity against neuropathogenic E. coli K1 at only 8 μg/mL as compared to individual components of the nanocomposite, whereas a 70 % inhibition of A. castellanii viability was observed at 50 μg/mL. Moreover, PPy-Co3O4-AgNPs were found to have minimal cytotoxicity against human keratinocytes HaCaT cells in vitro even at higher concentration (50 μg/mL), and also reduced the microbes-mediated cytopathogenicity against host cells.

    CONCLUSION: These results demonstrate that PPy-Co3O4-AgNPs hold promise in the development of novel antimicrobial nanomaterials for biomedical applications.

    KEY POINTS: •Synthesis of polypyrrole-cobalt oxide-silver (PPy-Co3O4-AgNPs) nanocomposite. •Antimicrobial activity of nanocomposite. •PPy-Co3O4-AgNPs hold promise for biomedical applications.

    Matched MeSH terms: Oxides
  19. Fulltext A comparative analysis of microleakage of three root end filling materials - an in vitro study
    Saini, D., Nadig, G., Saini, R.
    Archives of Orofacial Sciences, 2008;3(2):43-47.
    MyJurnal
    The main objective of a root end filling material is to provide an apical seal that prevents the movement of bacteria and the diffusion of bacterial products from the root canal system into periapical tissues. The aim of this study was to compare the microleakage of three root end filling materials Mineral trioxide aggregate (MTA), Glass ionomer cement (GIC) and Silver GIC (Miracle Mix) using dye penetration technique under stereomicroscope. Forty-five extracted human maxillary central incisors were instrumented and obturated with gutta percha using lateral compaction technique. Following this, the teeth were stored in saline. After one week, teeth were apically resected at an angle of 90ï° to the long axis of the root and root end cavities were prepared. The teeth were divided into three groups of fifteen specimens each and were filled with Group I -MTA, Group II - GIC and Group III - Miracle Mix. The samples were coated with varnish and after drying, they were immersed in 1% methylene blue dye for 72 hours. The teeth were then rinsed, sectioned longitudinally and observed under stereomicroscope. The depth of dye penetration was measured in millimeters. Microleakage was found to be significantly less in MTA (0.83 mm) when compared to GIC (1.32 mm) (p < 0.001) and with Miracle Mix (1.39 mm) (p < 0.001) No significant difference was found when microleakage in Miracle Mix was compared to that of GIC (p = 0.752). Thus we concluded that MTA is a better material as root end filling material to prevent microleakage, in comparison to GIC and Miracle Mix.
    Matched MeSH terms: Oxides
  20. Stimulation of Innate and Adaptive Immune Cells with Graphene Oxide and Reduced Graphene Oxide Affect Cancer Progression
    Yunus MA, Ramli MM, Osman NH, Mohamed R
    Arch Immunol Ther Exp (Warsz), 2021 Jul 29;69(1):20.
    PMID: 34327598 DOI: 10.1007/s00005-021-00625-6
    Sole nanomaterials or nanomaterials bound to specific biomolecules have been proposed to regulate the immune system. These materials have now emerged as new tools for eliciting immune-based therapies to treat various cancers. Graphene, graphene oxide (GO) and reduced GO (rGO) are the latest nanomaterials among other carbon nanotubes that have attracted wide interest among medical industry players due to their extraordinary properties, inert-state, non-toxic and stable dispersion in a various solvent. Currently, GO and rGO are utilized in various biomedical application including cancer immunotherapy. This review will highlight studies that have been carried out in elucidating the stimulation of GO and rGO on selected innate and adaptive immune cells and their effect on cancer progression to shed some insights for researchers in the development of various GO- and rGO-based immune therapies against various cancers.
    Matched MeSH terms: Oxides
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