Publications by authors named "Mostafa A Sayed"

To address escalating environmental and sustainability concerns of petroleum-based superplasticizers (SPs), this work aims to develop sustainable and eco-friendly starch-based SPs using gamma radiation for maintaining the desired workability of geopolymeric pastes. Specifically, two green SPs were prepared from starch via radiation-induced grafting of two sulfonic group-bearing monomers, namely 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and 4-styrene sulfonic acid sodium salt (Na4SS). The grafting reaction was improved by initial modification of starch with glycidyl methacrylate to insert vinyl groups into the starch backbone.

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Phase-change materials (PCMs) offer a compelling platform for active metaoptics, owing to their large index contrast and fast yet stable phase transition attributes. Despite recent advances in phase-change metasurfaces, a fully integrable solution that combines pronounced tuning measures, i.e.

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As renewable energy sources are either intermittent in nature or remote in location, developing cost-effective, sustainable, modular systems and technologies to store and transport renewables at an industrial scale is imperative. Storing cheap renewable electricity into chemical bonds (i.e.

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Utilizing solar energy for chemical transformations has attracted a growing interest in promoting the clean and modular chemical synthesis approach and addressing the limitations of conventional thermocatalytic systems. Under light irradiation, noble metal nanoparticles, particularly those characterized by localized surface plasmon resonance, commonly known as plasmonic nanoparticles, generate a strong electromagnetic field, excited hot carriers, and photothermal heating. Plasmonic nanoparticles enabling efficient absorption of light in the visible range have moderate catalytic activities.

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Lung failure is the main reason for mortality in COVID-19 patients, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, no drug has been clinically approved for treatment of COVID-19. Nanotechnology has a great potential in contributing significantly to the fight against COVID-19 by developing effective therapies that can selectively eradicate the respiratory virus load.

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Efficient hybrid plasmonic-photonic metasurfaces that simultaneously take advantage of the potential of both pure metallic and all-dielectric nanoantennas are identified as an emerging technology in flat optics. Nevertheless, postfabrication tunable hybrid metasurfaces are still elusive. Here, we present a reconfigurable hybrid metasurface platform by incorporating the phase-change material GeSbTe (GST) into metal-dielectric meta-atoms for active and nonvolatile tuning of properties of light.

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Development of optical nanobiosensors has emerged as one of the most important bioresearch areas of interest over the past decades especially in the modern innovations in the design and utilization of sensing platforms. The application of nanobiosensors has been accelerated with the introduction of plasmonic NPs, which overcome the most of the limitations in the case of conventional optical nanobiosensors. Since the plasmonic AuNPs-based nanobiosensors provide high potential achievements to develop promising platforms in fully integrated multiplex assays, some well-developed investigations are clearly required to improve the current technologies and integration of multiple signal inputs.

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New lanthanide complexes (1-3) of the general formulae [Ln(L)(NO)(HO)] have been synthesized by reaction of Ln(NO) {Ln = La (1), Sm (2) and Yb (3)} with 2,2'-(((1E,1'E)-thiophene-2,5-diylbis(methaneylylidene))bis(azaneylylidene))diphenol (HL). Based on elemental analysis, spectroscopic studies (UV-Vis., FT-IR, ESI-MS, H/C NMR), molar conductance and thermogravimetric analysis, the Schiff base ligand was suggested to coordinate Ln(III) ions through the azomethine nitrogens, deprotonated hydroxyl groups, and thiophene sulphur atom.

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Article Synopsis
  • There is a growing need for a better way to measure how gold nanoparticles (AuNPs) are taken up by cells due to their many uses in biology.
  • Currently, flow cytometry uses a 488 nm laser to detect AuNPs, but this method isn't very effective because it doesn't optimize the detection of these nanoparticles.
  • The study shows that using lasers with a longer wavelength (red-shifted) significantly improves the detection of AuNPs, specifically in triple negative breast cancer cells.
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Background: Gold nanoparticles (AuNPs) with unique physicochemical properties have received a great deal of interest in the field of biological, chemical and biomedical implementations. Despite the widespread use of AuNPs in chemical and biological sensing, catalysis, imaging and diagnosis, and more recently in therapy, no comprehensive summary has been provided to explain how AuNPs could aid in developing improved sensing and catalysts systems as well as medical settings.

Scope Of Review: The chemistry of Au-based nanosystems was followed by reviewing different applications of Au nanomaterials in biological and chemical sensing, catalysis, imaging and diagnosis by a number of approaches, and finally synergistic combination therapy of different cancers.

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We present a systematic study of the effect of higher-multipolar order plasmon modes on the spectral response and plasmonic coupling of silver nanoparticle dimers at nanojunction separation and introduce a coupling mechanism. The most prominent plasmonic band within the extinction spectra of coupled resonators is the dipolar coupling band. A detailed calculation of the plasmonic coupling between equivalent particles suggests that the coupling is not limited to the overlap between the main bands of individual particles but can also be affected by the contribution of the higher-order modes in the multipolar region.

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Over the past two decades, the development of plasmonic nanoparticle (NPs), especially gold (Au) NPs, is being pursued more seriously in the medical fields such as imaging, drug delivery, and theranostic systems. However, there is no comprehensive review on the effect of the physical and chemical parameters of AuNPs on their plasmonic properties as well as the use of these unique characteristic in medical activities such as imaging and therapeutics. Therefore, in this literature the surface plasmon resonance (SPR) modeling of AuNPs was accurately captured toward precision medicine.

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For localized tumors, gold nanorod (AuNR)-assisted plasmonic photothermal therapy (PPTT) is a potentially effective alternative to traditional surgery, in which AuNRs absorb near-infrared light and convert it to heat in order to kill cancer cells. However, for large tumors (volume ≥ 20 cm), an uneven distribution of AuNRs might cause inhomogeneity of the heat distribution inside the tumor. Surgery is frequently recommended for removing large tumors, but it is associated with a high risk of cancer recurrence and metastasis.

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We report for the first time the usage of plasmonically enhanced Raman spectroscopy (PERS) to directly monitor the dynamics of pharmacologically generated hemeoxygenase-1 (HO-1) by evaluating the kinetics of formation of carbon monoxide (CO), one of the metabolites of HO-1 activation, in live cells during cisplatin treatment. Being an endogenous signaling molecule, CO plays an important role in cancer regression. Many aspects of HO-1's and CO's functions in biology are still unclear largely due to the lack of technological tools for the real-time monitoring of their dynamics in live cells and tissues.

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While Li-ion battery cathode-electrolyte interfaces (CEIs) have been extensively investigated in recent decades, accurately identifying the chemical nature and tracking the dynamics of the CEIs during electrochemical cycling still remain a grand challenge. Here we report our findings in the investigation into the dynamic evolution of the interface between a LiNiCoMnO (LNMC) cathode and an ethylene carbonate/dimethyl carbonate (EC/DMC)-based electrolyte using surface-enhanced Raman spectroscopy (SERS) performed on a model cell under typical battery operating conditions. In particular, the strong SERS activity provided by a monolayer of Au nanocubes deposited on a model LNMC electrode (additive-free) enables quasi-quantitative assessment of the CEI evolution during cycling, proving information vital to revealing the dynamics of the species adsorbed on the LNMC surface as a function of cell potential.

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To date, a variety of biological assays such as immunostaining, western blotting, enzyme-linked immunosorbent assay (ELISA), and flow cytometry have been used to analyze and trace important biological events and therapies. In addition to these techniques, the application of microscopic analytical techniques such as matrix-assisted laser desorption/ionization-time of flight (MALDI-ToF) mass spectrometry and Raman spectroscopy is increasing, allowing information to be obtained at the molecular level. In this study, we have conducted real-time tracking of autophagy, a cellular process that has recently been attracting significant attention.

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An electrochemical nitrogen reduction reaction (NRR) could provide an alternative pathway to the Haber-Bosch process for clean, sustainable, and decentralized NH production when it is coupled with renewably derived electricity sources. Developing an electrocatalyst that overcomes sluggish kinetics due to the challenges associated with N adsorption and cleavage and that also produces NH with a reasonable yield and efficiency is an urgent need. Here, we engineer the size and density of pores in the walls of hollow Au nanocages (AuHNCs) by tuning their peak localized surface plasmon resonance (LSPR); in this way, we aim to enhance the rate of electroreduction of N to NH.

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Most cancer-related deaths come from metastasis. It was recently discovered that nanoparticles could inhibit cancer cell migration. Whereas most researchers focus on single-cell migration, the effect of nanoparticle treatment on collective cell migration has not been explored.

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Understanding the nature of interfacial defects of materials is a critical undertaking for the design of high-performance hybrid electrodes for photocatalysis applications. Theoretical and computational endeavors to achieve this have touched boundaries far ahead of their experimental counterparts. However, to achieve any industrial benefit out of such studies, experimental validation needs to be systematically undertaken.

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As a noninvasive molecular analysis technique, ultraviolet resonance Raman (UVRR) spectroscopy represents a label-free method suitable for characterizing biomolecules. Using UVRR spectroscopy, we collected spectral fingerprints of UV absorbing cellular components, including proteins, nucleic acids, and unsaturated lipids. This knowledge was used to guide the assignment of spectra derived from intact human cell lines (i.

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Ultraviolet resonance Raman (UVRR) spectroscopy is a label-free method to define biomacromolecular interactions with anticancer compounds. Using UVRR, we describe the binding interactions of two Pt(II) compounds, cisplatin (cis-diamminedichloroplatinum(II)) and its isomer, transplatin, with nucleotides and genomic DNA. Cisplatin binds to DNA and other cellular components and triggers apoptosis, whereas transplatin is clinically ineffective.

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Despite the important applications of near-infrared (NIR) absorbing nanomaterials in plasmonic photothermal therapy (PPT), their high yield synthesis and nonspecific heating during the active- and passive-targeted cancer therapeutic strategies remain challenging. In the present work, we systematically demonstrate that in situ aggregation of typical non-NIR absorbing plasmonic nanoparticles at the nuclear region of the cells could translate them into an effective NIR photoabsorber in plasmonic photothermal therapy of cancer due to a significant shift of the plasmonic absorption band to the NIR region. We evaluated the potential of nuclear-targeted AuNSs as photoabsorber at various stages of endocytosis by virtue of their inherent in situ assembling capabilities at the nuclear region of the cells, which has been considered as one of the most thermolabile structures within the cells, to selectively destruct cancer cells with minimal damage to healthy cells.

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To conquer cancer, one of the most dangerous and common diseases faced by humanity, many therapeutic approaches have been researched and developed. Discovery of highly effective therapeutic molecules without side effects and novel strategies for their effective delivery are areas receiving recent global interest. Here, we describe a facile one-pot synthetic method for making gold nanoparticles coated with fucoidan, a natural product extracted from brown seaweed and a promising anticancer biopolymer.

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Metastasis is responsible for most cancer-related deaths, but the current clinical treatments are not effective. Recently, gold nanoparticles (AuNPs) were discovered to inhibit cancer cell migration and prevent metastasis. Rationally designed AuNPs could greatly benefit their antimigration property, but the molecular mechanisms need to be explored.

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