Browsing by Author "Sabri, YM"

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    Mercury diffusion in gold and silver thin film electrodes on quartz crystal microbalance sensors.
    (Elsevier, 2009-03-28) Sabri, YM; Ippolito, SJ; Tardio, J; Atanacio, AJ; Sood, DK; Bhargava, SK
    Diffusion behavior of mercury into both gold and silver electrodes of polished and roughened quartz crystal microbalances (QCMs) is presented. Several QCM devices were exposed to mercury vapor for 8 h and allowed to desorb for 5 h under controlled nitrogen atmosphere. The process was repeated for different Hg concentrations of 1.02, 1.87 and 3.65mg/m3 at an elevated temperature of 40 °C. The chemical composition and surface morphology of each QCM surface was characterized by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS), Secondary Ion Mass Spectroscopy (SIMS), Atomic Force Microscope (AFM) and Field Emission Secondary Electron Microscope (FE-SEM). The Ag electrodeswere found to contain up to 16% more adsorbed/amalgamated Hg by mass than the Au samples. It was found that the ratio of amalgamated to adsorbed Hg is less for Au than Ag. SIMS analysis confirmed high Hg diffusion through rough substrates, 40 days after Hg exposure. In situ sticking probability of the tested mercury vapor concentrations to Au and Ag surfaces at 40 °C was found to drop at quicker rates than the reported Hg–Au and Hg–Ag room temperature values. Overall, in the context of Hg vapor phase gas sensing applications, the rougher gold substrate was found to outperform the other samples due to its superior adsorption/desorption properties. © 2008, Elsevier Ltd.
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    Mercury vapor sensor enhancement by nanostructured gold deposited on nickel surfaces using galvanic replacement reactions
    (Royal Society of Chemistry, 2012-07-16) Sabri, YM; Ippolito, SJ; Atanacio, AJ; Bansal, V; Bhargava, SK
    Anthropogenic mercury emission is a serious global environmental problem because of its toxicity to humans, plants and wildlife. In order to control these emissions, accurate and reliable online continuous mercury monitoring systems (CMMs) are critical. Such systems can notify appropriate authorities or provide feedback signals to a process control system in time, thus making them an integral part of monitoring and controlling Hg emissions. We demonstrate how nanostructured gold can easily be deposited in small quantities on nickel electrode based QCMs using galvanic replacement (GR) reactions with the resultant surface having excellent Hg monitoring properties. The developed GR surfaces were observed to have higher sensitivity and selectivity in the presence of interfering gas species (NH3 and H2O), as well as to have ∼80% higher mercury sorption capacity than the most efficient mercury sorbents reported to date. Investigations towards the Hg-sensing capabilities of the resultant Ni–Au surface based Hg sensors showed ∼50% better sensitivity and detection limit over control Au films. Furthermore, the GR based QCMs were found to self-regenerate without changing the operating temperature of the sensor, undergoing Hg desorption with sensor recoveries of 93.7–99.3% following Hg exposure at an operating temperature of 90 °C. Surface depth profile analysis of the Ni–Au electrode surfaces showed that the high recovery rate of the sensors was primarily due to the Ni–Au structures, which unlike continuous Au thin-films more commonly used for Hg sensing applications, do not accumulate Hg at the sensitive-layer–substrate interface. Furthermore, the GR Ni–Au surfaces were found to be highly selective towards Hg vapor in the presence of NH3 and H2O interfering gas species which makes them potentially suitable for operating in harsh industrial effluent environments.© The Royal Society of Chemistry 2012
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    Silver─gallium nano-amalgamated particles as a novel, biocompatible solution for antibacterial coatings
    (Wiley, 2023-11-05) Nguyen, TT; Zhang, PF; Bi, JW; Nguyen, NH; Dang, Y; Xu, ZN; Wang, H; Ninan, N; Bright, R; Pham, T; Nguyen, CK; Sabri, YM; Nguyen, MT; Vingsvivut, JP; Zhao, YP; Vasilev, K; Truong, VK
    Bacterial infections account for countless deaths globally. Antibiotics are the primary countermeasure; however, the alarming spread of antibiotic-resistant strains necessitates alternative solutions. Silver and silver compounds have emerged as promising antibacterial agents. However, issues related to cytotoxicity and genotoxicity of silver remain concern. To overcome these challenges, this proposes an easy-to-control and straightforward method to synthesize novel Silver─gallium (Ag─Ga) nano-amalgamated particles. Gallium liquid metal (GaLM) is used to facilitate the galvanic deposition of silver nanocrystals (Ag) on oxide layer. The GaLM not only serves as a carrier for silver through the galvanic replacement process, but also provides a controlled-release mechanism for silver, in this way improving biocompatibility, reducing inflammation, and stimulating bone growth. Notably, Ag─Ga suspensions can be conveniently deposited by spray-coating on a range of devices and material surfaces, effectively eliminating pathogenic bacteria with efficacy comparable to that of silver ions. In vivo studies in rat models affirm the antibacterial capabilities, especially against methicillin-resistant Staphylococcus aureus and Escherichia coli, when placed on implants such as titanium rods and magnesium discs. Furthermore, Ag─Ga promotes bone matrix formation and collagen growth without eliciting an inflammatory response, indicating a major promise for coatings on a wide variety of biomedical devices and materials. © 2023 The Authors. Published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License.
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    Transforming spirulina maxima biomass into ultrathin bioactive coatings using an atmospheric plasma jet: a new approach to healing of infected wounds
    (Wiley, 2023-09-15) Pham, T; Nguyen, TT; Nguyen, NH; Hayles, A; Li, WS; Pham, DQ; Nguyen, CK; Nguyen, T; Vongsvivut, JP; Ninan, N; Sabri, YM; Zhang, W; Vasiliev, K; Truong, VK
    The challenge of wound healing, particularly in patients with comorbidities such as diabetes, is intensified by wound infection and the accelerating problem of bacterial resistance to current remedies such as antibiotics and silver. One promising approach harnesses the bioactive and antibacterial compound C-phycocyanin from the microalga Spirulina maxima. However, the current processes of extracting this compound and developing coatings are unsustainable and difficult to achieve. To circumvent these obstacles, a novel, sustainable argon atmospheric plasma jet (Ar-APJ) technology that transforms S. maxima biomass into bioactive coatings is presented. This Ar-APJ can selectively disrupt the cell walls of S. maxima, converting them into bioactive ultrathin coatings, which are found to be durable under aqueous conditions. The findings demonstrate that Ar-APJ-transformed bioactive coatings show better antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Moreover, these coatings exhibit compatibility with macrophages, induce an anti-inflammatory response by reducing interleukin 6 production, and promote cell migration in keratinocytes. This study offers an innovative, single-step, sustainable technology for transforming microalgae into bioactive coatings. The approach reported here has immense potential for the generation of bioactive coatings for combating wound infections and may offer a significant advance in wound care research and application. © 2023 The Authors. Small published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License.