Trehalose-FunctionalizedMagnetic Affinity Probe ProvidesBiochemical Evidence of Nanoparticle Internalization in Mycobacteria

A new trehalose-grafted poly(2-hydroxyethyl methacrylate) (HEMA) glycopolymer was synthesized via the perfluorophenyl azide (PFPA)-mediated Staudinger reaction between poly(HEMA-co-HEMA-PFPA) and a diphenylphosphine-derivatized trehalose. The reaction occurred rapidly at room temperature without the use of any catalyst, giving the trehalose glycopolymers over 68% yield after 1 h. The grafting density of trehalose can be controlled by the copolymer composition in poly(HEMA-co-HEMA-PFPA), resulting in 6.1% (TP1) or 37% (TP2) at 10:1 and 1:1 HEMA/HEMA-PFPA feed ratio, respectively. The trehalose glycopolymer was covalently attached on glass slides or silicon wafers using a thin film of poly(HEMA-co-HEMA-PFPA) as the adhesion layer, achieved through the C-H insertion reaction of the photogenerated singlet perfluorophenyl nitrene. To demonstrate the ability of the trehalose glycopolymer to capture mycobacteria, arrays of the trehalose glycopolymer were fabricated and treated with Mycobacterium smegmatis. Results from the optical, fluorescence, and scanning electron microscopy showed that mycobacteria were indeed captured on the trehalose glycopolymer. The amount of mycobacteria captured increased with the percent trehalose in the trehalose glycopolymer and also with the concentration of the trehalose glycopolymer. In addition, the captured bacteria could be visualized by the naked eye under the illumination of a hand-held UV lamp.

Synergistic activities of magnetic iron-oxide nanoparticles and stabilizing ligands containing ferrocene moieties in selective oxidation of benzyl alcohol

Background:: Magnetic materials like iron, nickel, and cobalt have been a subject of interest among the scientific and research community for centuries. Owing to their unique properties, they are prevalent in the mechanical and electronic industries. In recent times, magnetic materials have undeniable applications in biotechnology and nanomedicine. Bacteria like Salmonella enterica, Clostridium botulinum, Bacillus subtilis, etc, pose a hazard to human health and livestock. This ultimately leads to huge yields and economic losses on a global scale. Antimicrobial resistance has become a significant public health concern in recent years, with the increasing prevalence of drugresistant infections posing a significant threat to global health. Many coherent studies have successfully reported magnetic metal oxide nanoparticles to be highly selective, specific, and effective in neutralizing pathogens through various mechanisms like cell membrane disruption, direct contact-mediated killing, or by generating Reactive Oxygen Species (ROS) and numerous costimulatory and inflammatory cytokines. Therefore, we explored the inhibitory effects of iron oxide nanoparticles (NPs) on various pathogenic bacteria via an in-silico approach. This method helped us to understand the active sites where the iron oxide NPs bind with the bacterial proteins. Methods:: The 3D crystal structures of all the pathogenic proteins of Streptococcus pneumoniae, Pseudomonas aeruginosa, Vibrio cholerae, Salmonella enterica, Shigella flexneri, Clostridium botulinum and nanoparticles (Fe2O3 and Fe3O4) under study were downloaded from RCSB PDB and ChemSpider official websites respectively. It was followed by the in-silico molecular Docking using PyRx and AutoDock Vina and analyzed on LigPlot. Results:: This study interprets the efficacy of the Fe2O3 and Fe3O4 nanoparticles against all the test bacteria. At the same time, Fe2O3 and Fe3O4 formed the most stable complexes with cholera enterotoxin subunit B and lectin II (PA-IIL) mutant S23A of Pseudomonas aeruginosa, respectively. Conclusion:: As in this era of AMR, researchers have been exploring alternative strategies to combat bacterial infections, including using magnetic nanoparticles as a potential treatment. They possess unique physical and chemical properties that make them attractive candidates for antimicrobial therapy, including their ability to penetrate bacterial biofilms and selectively target pathogenic bacteria while leaving healthy cells unharmed. This study examined the inhibitory effects of iron oxide (magnetic) nanoparticles, namely Fe2O3 and Fe3O4, on various bacterial proteins involved in cell-to-cell interactions and pathogenesis.

In this study, magnetic polymeric nanoparticles were prepared use in for targeted drug delivery. First, iron oxide (Fe3O4) magnetic nanoparticles (MNPs) were synthesized by coprecipitation with ferrous and ferric chloride salts. Then, to render the MNPs hydrophobic, the surfaces were covered with oleic acid. Finally, the hydrophobic MNPs (H-MNPs) were encapsulated with polymer. The emulsion evaporation technique was used for the preparation of polymer-coated H-MNP. Poly(dl-lactide-co-glycolide) (PLGA) and chitosan-modified PLGA were used as polymers. The polymeric nanoparticles were characterized and compared. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, small-angle X-ray scattering, size distribution, ζ potential, magnetic properties, and magnetite entrapment efficiency measurements were performed to investigate the properties of the nanoparticles. The XTT assay was performed to understand the biocompatibility (i.e., toxicity) of MNPs and magnetic polymeric nanoparticles to MCF-7 cells.

Applications of magnetic targeting in diagnosis and therapy--possibilities and limitations: a mini-review.

Nitric oxide (NO) is involved in several physiological and pathophysiological processes, such as control of vascular tone and immune responses against microbes. Thus, there is great interest in the development of NO-releasing materials to carry and deliver NO for biomedical applications. Magnetic iron oxide nanoparticles have been used in important pharmacological applications, including drug-delivery. In this work, magnetic iron oxide nanoparticles were coated with thiol-containing hydrophilic ligands: mercaptosuccinic acid (MSA) and dimercaptosuccinic acid (DMSA). Free thiol groups on the surface of MSA- or DMSA- coated nanoparticles were nitrosated, leading to the formation of NO-releasing iron oxide nanoparticles. The cytotoxicity of MSA- or DMSA-coated magnetic nanoparticles (MNP) (thiolated nanoparticles) and nitrosated MSA- or nitrosated DMSA- coated MNPs (NO-releasing nanoparticles) were evaluated towards human lymphocytes. The results showed that MNP-MSA and MNP-DMSA have low cytotoxicity effects. On the other hand, NO-releasing MNPs were found to increase apoptosis and cell death compared to free NO-nanoparticles. Therefore, the cytotoxicity effects observed for NO-releasing MNPs may result in important biomedical applications, such as the treatment of tumors cells.

Magnetic iron oxide nanoparticles (MNPs) have been under intense investigation for at least the last five decades as they show enormous potential for many biomedical applications, such as biomolecule separation, MRI imaging and hyperthermia. Moreover, a large area of research on these nanostructures is concerned with their use as carriers of drugs, nucleic acids, peptides and other biologically active compounds, often leading to the development of targeted therapies. The uniqueness of MNPs is due to their nanometric size and unique magnetic properties. In addition, iron ions, which, along with oxygen, are a part of the MNPs, belong to the trace elements in the body. Therefore, after digesting MNPs in lysosomes, iron ions are incorporated into the natural circulation of this element in the body, which reduces the risk of excessive storage of nanoparticles. Still, one of the key issues for the therapeutic applications of magnetic nanoparticles is their pharmacokinetics which is reflected in the circulation time of MNPs in the bloodstream. These characteristics depend on many factors, such as the size and charge of MNPs, the nature of the polymers and any molecules attached to their surface, and other. Since the pharmacokinetics depends on the resultant of the physicochemical properties of nanoparticles, research should be carried out individually for all the nanostructures designed. Almost every year there are new reports on the results of studies on the pharmacokinetics of specific magnetic nanoparticles, thus it is very important to follow the achievements on this matter. This paper reviews the latest findings in this field. The mechanism of action of the mononuclear phagocytic system and the half-lives of a wide range of nanostructures are presented. Moreover, factors affecting clearance such as hydrodynamic and core size, core morphology and coatings molecules, surface charge and technical aspects have been described.Graphical

Magnetic iron oxide nanoparticles were obtained for the first time via the green chemistry approach, starting from two aqueous extracts of wormwood (Artemisia absinthium L.), both leaf and stems. In order to obtain magnetic nanoparticles suitable for medical purposes, more precisely with hyperthermia inducing features, a synthesis reaction was conducted, both at room temperature (25 °C) and at 80 °C, and with two formulations of the precipitation agent. Both the quality and stability of the synthesized magnetic iron oxide nanoparticles were physiochemically characterized: phase composition (X-ray powder diffraction (XRD)), thermal behavior (thermogravimetry (TG) and differential scanning calorimetry (DSC)), electron microscopy (scanning (SEM) and transmission (TEM)), and magnetic properties (DC and HF-AC). The magnetic investigation of the as-obtained magnetic iron oxide nanoparticles revealed that the synthesis at 80 °C using a mixture of NaOH and NH3(aq) increases their diameter and implicitly enhances their specific absorption rate (SAR), a mandatory parameter for practical applications in hyperthermia.

Nitration of aromatic compounds is an important industrial process, which creates significant environmental pollution because of the harsh mineral acid catalysts. In this work, we report the synthesis and application of magnetic iron oxide nanoparticles as green catalysts for aromatic nitration. Magnetic iron oxide nanoparticles were synthesized by co-precipitation method and tested for nitration reactions on selected aromatic substrates, phenol, benzaldehyde, methylbenzoate, [Formula: see text]-cresol and [Formula: see text]-cresol. For the nitration reactions, sodium nitrite was used as the nitro-source and hydrogen peroxide as the oxidant. Effect of reaction conditions like, solvent, temperature and microwave treatment were studied. The magnetic nanoparticles were found to be more stable after coating with a carbon shell by a one-pot carbonization method. The reactions were fast with good product yield under solvent-free microwave conditions. The nano-catalyst was recovered magnetically after the reaction and reused for three batches of nitration, without significant loss in catalytic activity. The nanoparticles were characterized using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometry (XRD) and FTIR spectroscopy.

Magnetic nanoparticles have been intensively investigated due to their magnetic characteristics, quantum dot effects, as well as their potential applications in the area of bioscience and medicine. Very promising nanoparticles are magnetic iron oxide nanoparticles with appropriate surface modification which have been widely used experimentally for masses of in vivo applications such as magnetic resonance imaging contrast enhancement, drug delivery, and hyperthermia, etc.. All these biomedical applications require that these nanoparticles have effective magnetic values and suitable sizes. On the other hand, these applications need special surface modification of these particles, which not only have to be non-toxic and biocompatible, but also allow a targetable drug delivery in a specific area. This review summarizes the current research situation and development of magnetic iron oxide nanoparticles, and the biomedical applications ranging from drug delivery to hyperthermia for tumor-targeted therapy.

Recent advances in nanoscience suggest that the existing issues involving water quality could be resolved or greatly improved using nanomaterials, especially magnetic iron oxide nanoparticles. Magnetic nanoparticles have been synthesized for the development and use, in association with natural coagulant protein for water treatment. The nanoparticles size, morphology, structure, and magnetic properties were characterized by transmission electron microscope, X-ray diffraction, and superconducting quantum interference device magnetometry. Purified Moringa oleifera protein was attached onto microemulsions-prepared magnetic iron oxide nanoparticles (ME-MION) to form stable protein-functionalized magnetic nanoparticles (PMO+ME-MION). The turbidity removal efficiency in both synthetic and surface water samples were investigated and compared with the commonly used synthetic coagulant (alum) as well as PMO. More than 90 % turbidity could be removed from the surface waters within 12 min by magnetic separation of PMO+ME-MION; whereas gravimetrically, 70 % removal in high and low turbid waters can be achieved within 60 min. In contrast, alum requires 180 min to reduce the turbidity of low turbid water sample. These data support the advantage of separation with external magnetic field (magnetophoresis) over gravitational force. Time kinetics studies show a significant enhancement in ME-MION efficiency after binding with PMO implying the availability of large surface of the ME-MION. The coagulated particles (impurities) can be removed from PMO+ME-MION by washing with mild detergent or cleaning solution. To our knowledge, this is the first report on surface water turbidity removal using protein-functionalized magnetic nanoparticle.

The fluorescent probes having complete spectral separation between absorption and emission spectra (large Stokes shift) are highly useful for solar concentrators and bioimaging. In bioimaging application, NIR fluorescent dyes have a greater advantage in tissue penetration depth compared to visible-emitting organic dyes or inorganic quantum dots. Here we report the design, synthesis, and characterization of an amphiphilic polymer, poly(isobutylene-alt-maleic anhyride)-functionalized near-infrared (NIR) IR-820 dye and its conjugates with iron oxide (Fe3O4) magnetic nanoparticles (MNPs) for optical and magnetic resonance (MR) imaging. Our results demonstrate that the Stokes shift of unmodified dye can be tuned (from ~106 to 208 nm) by the functionalization of the dye with polymer and MNPs. The fabrication of bimodal probes involves (i) the synthesis of NIR fluorescent dye (IR-820 cyanine) functionalized with ethylenediamine linker in high yield, >90%, (ii) polymer conjugation to the functionalized NIR fluorescent dye, and (iii) grafting the polymer-conjugated dyes on iron oxide MNPs. The resulting uniform, small-sized (ca. 6 nm) NIR fluorescent dye-magnetic hybrid nanoparticles (NPs) exhibit a wider emissive range (800-1000 nm) and minimal cytotoxicity. Our preliminary studies demonstrate the potential utility of these NPs in bioimaging by means of direct labeling of cancerous HeLa cells via NIR fluorescence microscopy and good negative contrast enhancement in T2-weighted MR imaging of a murine model.

Magnetic iron oxide nanoparticles are relatively advanced nanomaterials, and are widely used in biology, physics and medicine, especially as contrast agents for magnetic resonance imaging. Characterization of the properties of magnetic nanoparticles plays an important role in the application of magnetic particles. As a contrast agent, the relaxation rate directly affects image enhancement. We characterized a series of monodispersed magnetic nanoparticles using different methods and measured their relaxation rates using a 0.47 T low-field Nuclear Magnetic Resonance instrument. Generally speaking, the properties of magnetic nanoparticles are closely related to their particle sizes; however, neither longitudinal relaxation rate nor transverse relaxation rate changes monotonously with the particle size . Therefore, size can affect the magnetism of magnetic nanoparticles, but it is not the only factor. Then, we defined the relaxation rates (i = 1 or 2) using the induced magnetization of magnetic nanoparticles, and found that the correlation relationship between relaxation rate and relaxation rate is slightly worse, with a correlation coefficient of = 0.8939, while the correlation relationship between relaxation rate and relaxation rate is very obvious, with a correlation coefficient of = 0.9983. The main reason is that relaxation rate is related to the magnetic field inhomogeneity, produced by magnetic nanoparticles; however relaxation rate is mainly a result of the direct interaction of hydrogen nucleus in water molecules and the metal ions in magnetic nanoparticles to shorten the relaxation time, so it is not directly related to magnetic field inhomogeneity.

<p>Nanoparticles are smaller than 100nm. Size of particle depends upon the method that is used for synthesis of nanoparticles. Magnetic nanoparticles consist of iron, cobalt and nickel and their chemical compounds. Their safety or toxicity is major concern for use in food. Magnetite, hematite and meghemite are types of magnetic nanoparticles. Magnetite (Fe3O4) common among the magnetic iron oxide nanoparticle that is used in food industry. Magnetite is getting popular due to its super paramagnetic properties and lack of toxicity to humans. Different methods are used to synthesize magnetic nanoparticles. Upon contact with air these particles loses magnetism and mono-dispersibility. To overcome this problem these nanoparticles are coated with natural or synthetic polymers, metals, organic and inorganic substances to create stable and hydrophilic nanostructures. Due to easy separation with magnet these magnetic nanoparticles are used as an affinity probe to remove bacteria from different food samples and have food related applications e.g, protein purification, enzyme immobilization and food analysis. These magnetic nanoparticles also used for removal of heavy metals and used in medical field.</p>

Nanoparticles are theranostic agents exerting both therapeutic and diagnostic purposes. Metallic nanoparticles can image tumor tissues by means of active and passive targeting. Many magnetic nanoparticles are currently approved by FDA. Hydrogel magnetic nanoparticle can carry chemotherapeutic agents and tumor-associated biomolecular binding with good magnetic susceptibility. Dextran-coated magnetic nanoparticles caused accurate cancer nodal staging. Many chemotherapeutics, e.g., methotrexate, doxorubicin, and paclitaxel were formulated with metallic nanoparticles. The uptake of gold and iron oxide nanoparticles conjugated with antibody against cancer antigens increased the precise cancer cells targeting. Multimodal multifunctional nanoparticles (as magnetic nanoparticles) are nanoparticles having different functional abilities in a single stable unit, e.g., a core nanoparticle attached to specific targeting ligands (for the surface molecules on target cells) and an imaging agent to trace the transport progress. Magnetic nanoparticles are excellent biosensors and bioimaging (contrast agents) agents upon using multiple imaging modalities. We suggest using multimodal multifunctional magnetic nanoparticles formed of magnetic nanoparticles conjugated with anti-ferritin antibody (to target surface cancer cells’ ligands), positive charges (to target lactate of Warburg’s effect), and anti-integrin antibodies (to target integrins on cancer cells surface) and to be coupled with high MRI resolution. Adjusting the size and surface coatings of magnetic nanoparticles using future research may reduce toxicity and improve magnetic behaviors. By focusing on improving their drug loading capacity, and increasing their specificity and affinity to target cancer cells, magnetic and multimodal nanoparticles may become suitable for clinical use with integrated imaging and multimodal therapy in the near future and dramatically impact the treatment of cancer.KeywordsTheranostic agentsMetallic nanoparticlesMultimodal multifunctional magnetic nanoparticlesTumour imagingAnimal modelWarburg effect