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This study's main objective was to fabricate an innovative three-dimensional microfluidic platform suitable for well-controlled chemical syntheses required for producing fine-tuned nanostructured materials. This work proposes using vortex mixing principles confined within a 3D multilayered microreactor to synthesize magnetic core-shell nanoparticles with tailored dimensions and polydispersity. The newly designed microfluidic platform allowed the simultaneous obtainment of Fe3O4 cores and their functionalization with a salicylic acid shell in a short reaction time and under a high flow rate. Synthesis optimization was also performed, employing the variation in the reagents ratio to highlight the concentration domains in which magnetite is mainly produced, the formation of nanoparticles with different diameters and low polydispersity, and the stability of colloidal dispersions in water. The obtained materials were further characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM), with the experimental results confirming the production of salicylic acid-functionalized iron oxide (Fe3O4-SA) nanoparticles adapted for different further applications. [ABSTRACT FROM AUTHOR]

Metal pollution has become a worldwide problem, mainly because of the toxicity, effects on living organisms, and the impact on the food chain and the quality of drinking water. Researchers have been focusing on developing new materials through green chemistry methods in order to remove these pollutants from the environment. In the recent decades, due to their unique properties, magnetic nanostructures containing functionalized polymers as shells have been demonstrated to be useful in water and wastewater treatment for this application. In this study, we report the synthesis and characterization of hybrid magnetic core-shell nanostructures including magnetite as the inorganic core and poly(benzofuran-co-arylacetic acid) functionalized with Nα, Nα'–bis(carboxymethyl)-L-lysine as the organic shell. These nanomaterials were used in the adsorption of different metal ions from aqueous solutions and contaminated water samples collected from Roșia River (Roșia Montană, Romania), representing attractive alternatives for water and/or wastewater treatment. The properties of the magnetic hybrid nanostructures were investigated by Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), magnetization measurements. The heavy metal concentrations in aqueous solutions were determined by flame atomic absorption spectrometry (FAAS). [ABSTRACT FROM AUTHOR]

New support was fabricated to enhance the enzyme activity of cellulase following immobilization. Functionalized core-shell magnetic gold nanoparticles were prepared and characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cellulase enzyme was immobilized on support via covalent bonding. The successful binding of the enzyme was chemically confirmed by Fourier-transform infrared spectroscopy (FTIR). The binding efficiency was 84% determined by Bradford assay. Filter Paper Activity (FPase) method was used to measure the enzyme activity at different temperatures (35–75 °C) and pH (2–8). The immobilized cellulase maintained 73% of its initial catalytic activity after 9 h and its activity is 0.78 mmol.ml−1. The newly designed nano-system also enhanced the thermal stability of immobilized cellulase in comparison to free cellulase and facilitated its long term storage. [ABSTRACT FROM AUTHOR]

This work describes a new synthesis method for core–shell magnetite nanoparticles with a secondary silica shell, functionalized with a linker system (Fe3O4-PABA-SiO2-linker) using a microwave-assisted heating technique. The functionalized solid nanomaterial was used for the nanophase synthesis of peptides (Fmoc route) as a solid support. The co-precipitation method was selected to obtain magnetite nanoparticles and sol–gel technique for silica coating using a microwave-assisted (MW) procedure. The magnetic properties of the nanoparticle core offer the advantage of a quick and easy alternative for the magnetic separation of the product from the reaction mixture, facilitating all the intermediary washing and separation operations. The intermediate and final materials were analyzed by advanced characterization methods. The effectiveness of the nanophase peptide synthesis using this nanostructured material as solid support was demonstrated for a short peptide sequence.

• Dual-tumor targeting theranostic platform based on magnetic nitric oxide-releasing nanoparticles was described. • External force guidance as well as internal active synergetic targeting strategy achieved targeting diagnosis and therapy. • In vitro and in vivo investigation confirmed the effective theranostic system. The external force guided targeting strategy, as well as the in vivo active targeting strategy based on "ligands-receptors" on the targeting cells and tissues have attracted much research interest. Herein, a kind of hyaluronic acid (HA) and folic acid (FA) modified magnetic S -nitrosothiols core-shell nanoparticles for nitric oxide (NO) control release as dual-tumor targeting theranostic platform were described, combining the external guidance and internal active targeting properties. Confocal microscopy assay and cells cytotoxicity experiments confirmed the active tumor cells targeting recognition, cells uptake, and NO initiated cytotoxicity of the HA-FA external functional layer modified S -nitrosothiols nanoparticles in vitro. In vivo magnetic resonance imaging (MRI) characterization, bio-distribution assay in organs and tumor, significant tumor inhibition efficacy, survival units of the mice bearing tumor, as well as the systemic toxicity assay demonstrated the efficiency of cooperative tumor targeting diagnosis and controlled NO-releasing chemotherapy. To the best of our knowledge, this is the first time of the external magnet and HA-FA actively induced synergistic effect tumor targeting systems based on NO chemotherapy in vivo , serving as a new theranostic system. [ABSTRACT FROM AUTHOR]

• Core-shell (CS) magnetic hexagonal mesoporous silica (HMS) nanoparticles were synthesized. • The magnetite core improved CO 2 adsorption. • CS and HMS were impregnated with tetraethylenepentamine. • Amine-impregnated CS showed much higher CO 2 uptakes than the corresponding HMS without magnetic core. • The magnetite core promoted finer dispersion of amine functionalities inside the silica pore. Post-combustion capture technology appears a suitable approach to reduce the emission of CO 2 by power plants. The use of solid sorbents would permit to overcome the limitations of the well-established liquid amine-based absorption process. In particular, mesoporous silica materials have been proposed as suitable sorbents especially if functionalized with amines. The properties of as-synthesized (by using dodecylamine as synthesis amine) and calcined hexagonal mesoporous silica (HMS), impregnated or not with tetraethylenepentamine (TEPA), were studied. Magnetite (Fe 3 O 4) nanoparticles were specifically used to obtain HMS core-shell nanoparticles in order to investigate the effect of the magnetite core on CO 2 uptake capability. CO 2 uptake measurements were carried out on all HMS and core-shell particles. Furthermore, Transmission Electron Microscopy (TEM) images, Fourier Transform Infrared (FTIR) spectra and N 2 adsorption/desorption measurements allowed analyzing some important properties of the sorbent particles, such as particle aggregation, incorporation and dispersion of amines, surface area, pore volume and pore size distribution. The best performance in terms of chemical CO 2 uptake was obtained on core-shell material, calcined and impregnated with TEPA (about 89 mg/g), but also the as prepared core-shell sample impregnated with TEPA seems promising since the synthesis dodecylamine sites can be activated during the impregnation process. [Display omitted] [ABSTRACT FROM AUTHOR]

A magnetoelastic (ME) biosensor for wireless detection of analytes in liquid is described. The ME biosensor was tested against human IgG in the range 0–20 μg∙mL−1. The sensing elements, anti-human IgG produced in goat, were immobilized on the surface of the sensor by using a recently introduced photochemical immobilization technique (PIT), whereas a new amplification protocol exploiting gold coated magnetic nanoparticles (core-shell nanoparticles) is demonstrated to significantly enhance the sensitivity. The gold nanoflowers grown on the magnetic core allowed us to tether anti-human IgG to the nanoparticles to exploit the sandwich detection scheme. The experimental results show that the 6 mm × 1 mm × 30 μm ME biosensor with an amplification protocol that uses magnetic nanoparticles has a limit of detection (LOD) lower than 1 nM, works well in water, and has a rapid response time of few minutes. Therefore, the ME biosensor is very promising for real-time wireless detection of pathogens in liquids and for real life diagnostic purpose.

In recent decades, it has been shown that magnetic nanomaterials, especially those formed by metal oxides, can be used in various fields due to their unique properties. To improve the efficiency of these nanoparticles, they have been covered by polymers or functionalized. In this work, we report the synthesis and characterization of hybrid magnetic core-shell nanostructures with inorganic cores consisting of magnetite surface-functionalized by o-phosphorylethanolamine and an organic shell formed by poly(benzofurane-co-arylacetic acid). For the attachment of the polymer chain on the preformed functionalized magnetite, the "grafting-from" strategy was applied, where the opening of the lactone ring is caused by amino groups at the nanoparticle surface. The properties of the magnetic-polymer hybrid nanostructures were investigated by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, thermogravimetric analysis, and magnetization measurements. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles have been extensively explored for the development of platforms for drug delivery and imaging probes. In this work, we have used a modular capping strategy to produce magnetic gold-coated Fe 3 O 4 (Fe 3 O 4 @Au) nanoparticles, which have been decorated with a copper (II) complex containing a thioether derivative of clip-phen (Fe 3 O 4 @Au@Cu), where the complex [Cu(2CP-Bz-SMe)] 2+ has affinity to bind DNA and proven nuclease activity (2CP-Bz-SMe=1,3-bis((1,10-phenanthrolin-2-yl)oxy)- N -(4-(methylthio)benzylidene)propan-2-imine). The functionalization of Fe 3 O 4 @Au with the copper complex occurs through the sulfur atom of the thioether moiety, as indicated by Raman scattering on surface. The magnetic measurements showed the nanomaterial Fe 3 O 4 @Au@Cu is still magnetic although the gold shell and the functionalization with the copper complex have diminished the magnetization due to the dilution of the magnetic core. The nuclease assays performed with Fe 3 O 4 @Au@Cu indicate that the nuclease activity of the nanomaterial toward the plasmid DNA involves an oxidative pathway in which H 2 O 2 species is involved as intermediate in a Fenton-like reaction. Based on the electron paramagnetic resonance spectra (a N  = 15.07 G, a H  = 14.99 G), such nuclease activity is assigned, essentially, to the HO species indicating that the radical production property of [Cu(2CP-Bz-SMe)] 2+ is successfully transferred to the core-shell gold-coated Fe 3 O 4 magnetic nanoparticles. To the best of our knowledge, this is the first study reporting nuclease activity due to the reactive oxygen species generated by a copper complex immobilized on a gold-coated magnetic nanoparticle. [ABSTRACT FROM AUTHOR]

The paper reports on the first successful fabrication of Co-graphene composites by electrochemical deposition of Co nanoparticles (NPs) on the sheets of twisted graphene. Characterization of the surface morphology and element mapping of twisted graphene decorated with Co NPs by transmission and scanning electron microscopy in combination with the energy-dispersive X-ray spectroscopy reveals the formation of isolated quasi-spherical oxidized Co NPs with the mean diameter 〈  d 〉 ≈ 220 nm and core-shell structure. X-ray photoelectron spectroscopy indicates that the core of deposited NPs consists of metal Co while the shell is CoO. Composite Co-graphene samples containing core-shell NPs reveal an exchange bias field up to 160 Oe at 4 K as detected by vibrating sample magnetometry after the field cooling procedure. [ABSTRACT FROM AUTHOR]

Background. Cerium oxide nanoparticles present the mimetic activity of superoxide dismutase, being able to inactivate the excess of reactive oxygen species (ROS) correlated with a large number of pathologies, such as stents restenosis and the occurrence of genetic mutations that can cause cancer. This study presents the synthesis and biological characterisation of nanoconjugates based on nanoparticles of iron oxide interconnected with cerium oxide conjugates. Methods. The synthesis of magnetite-nanoceria nanoconjugates has been done in several stages, where the key to the process is the coating of nanoparticles with polyethyleneimine and its chemical activation-reticulation with glutaraldehyde. The nanoconjugates are characterised by several techniques, and the antioxidant activity was evaluated in vitro and in vivo. Results. Iron oxide nanoparticles interconnected with cerium oxide nanoparticles were obtained, having an average diameter of 8 nm. Nanoconjugates prove to possess superparamagnetic properties and the saturation magnetisation varies with the addition of diamagnetic components in the system, remaining within the limits of biomedical applications. In vitro free-radical scavenging properties of nanoceria are improved after the coating of nanoparticles with polyethylenimine and conjugation with magnetite nanoparticles. In vivo studies reveal increased antioxidant activity in all organs and fluids collected from mice, which demonstrates the ability of the nanoconjugates to reduce oxidative stress. Conclusion. Nanoconjugates possess magnetic properties, being able to scavenge free radicals, reducing the oxidative stress. The combination of the two properties mentioned above makes them excellent candidates for theranostic applications.

Core–shell magnetic molecularly imprinted polymers (MIPs) nanoparticles (NPs), in which a Rhodamine B-imprinted layer was coated on Fe 3 O 4 NPs. were synthesized. First, Fe 3 O 4 NPs were prepared by a coprecipitation method. Then, amino-modified Fe 3 O 4 NPs (Fe 3 O 4 @SiO 2 -NH 2 ) was prepared. Finally, the MIPs were coated on the Fe 3 O 4 @SiO 2 -NH 2 surface by the copolymerization with functional monomer, acrylamide, using a cross-linking agent, ethylene glycol dimethacrylate; an initiator, azobisisobutyronitrile and a template molecule, Rhodamine B. The Fe 3 O 4 @MIPs were characterized using a scanning electron microscope, Fourier transform infrared spectrometer, vibrating sample magnetometer, and re-binding experiments. The Fe 3 O 4 @MIPs showed a fast adsorption equilibrium, a highly improved imprinting capacity, and significant selectivity; they could be used as a solid-phase extraction material and detect illegal addition Rhodamine B in food. A method was developed for the selective isolation and enrichment of Rhodamine B in food samples with recoveries in the range 78.47–101.6% and the relative standard deviation was <2%. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new generation of green, magnetic, reusable, and cost effective nano-catalyst is introduced. [•] Two heterogeneous, solid sulfonic acids, 1 and 2, are synthesized and compared in catalytic water-generating reactions. [•] Catalyst 2 was superior due to its bifunctionality, higher water-tolerance and hydrophobicity. [ABSTRACT FROM AUTHOR]

Abstract: The non-equilibrium dynamics of a single cubic core–shell ferrimagnetic nanoparticle system under a time dependent oscillating magnetic field is elucidated by making use of a classical Monte Carlo simulation technique with a standard Metropolis algorithm. Many interesting and unusual thermal and magnetic behaviors are observed, for instance, the locations of dynamic phase transition points change significantly depending upon amplitude and period of the external magnetic field as well as other Hamiltonian parameters in related planes. Much effort has also been devoted to the influences of the varying shell thickness on the thermal and magnetic properties of the particle, and outstanding physical findings are reported in order to better understand the dynamic process of the studied nanoparticle system. [Copyright &y& Elsevier]

Abstract: Previous attempts to review the literature on magnetic nanomaterials for hyperthermia-based therapy focused primarily on magnetic fluid hyperthermia (MFH) using mono metallic/metal oxide nanoparticles. The term “hyperthermia” in the literature was also confined only to include use of heat for therapeutic applications. Recently, there have been a number of publications demonstrating magnetic nanoparticle-based hyperthermia to generate local heat resulting in the release of drugs either bound to the magnetic nanoparticle or encapsulated within polymeric matrices. In this review article, we present a case for broadening the meaning of the term “hyperthermia” by including thermotherapy as well as magnetically modulated controlled drug delivery. We provide a classification for controlled drug delivery using hyperthermia: Hyperthermia-based controlled drug delivery through bond breaking (DBB) and hyperthermia-based controlled drug delivery through enhanced permeability (DEP). The review also covers, for the first time, core–shell type magnetic nanomaterials, especially nanoshells prepared using layer-by-layer self-assembly, for the application of hyperthermia-based therapy and controlled drug delivery. The highlight of the review article is to portray potential opportunities for the combination of hyperthermia-based therapy and controlled drug release paradigms -towards successful application in personalized medicine. [Copyright &y& Elsevier]

The synthesis of core-shell (Fe 3 O 4 @SiO 2) magnetic nanoparticles (MNP) functionalized using a Schiff base ligand (bis(3-methoxysalicylaldehyde)-o-phenylenediimine; MeOSalophen) for uranium extraction is reported. Extractive performances with respect to pH, adsorption kinetics, chemical nature of the equilibration phase, and elemental selectivity were evaluated and a maximal adsorption capacity of 92 mg g−1 at pH 6 in presence of sulfate ions for an equilibration time of 4 h was determined. The functionalized MNP offer very high affinity for uranyl ion (K d > 11,000 mL g−1) as well as a high degree of selectivity for this element over several metal ions present in leach liquors containing rare earth elements. While Th was also extracted with the functionalized MNP, equivalent extractive performances were achieved with the non-functionalized counterpart, suggesting that this element is most likely adsorbed on the surface of the silica coating layer. The Schiff base-functionalized core-shell nanoparticles also exhibited a high degree of reusability in the conditions tested. • Synthesis of a new functional magnetic nanomaterial (Fe 3 O 4 @SiO 2 -MeoSalophen) • High degree of selectivity for U(VI) in H 2 SO 4 leach liquor over several heavy metals and rare earth elements. • Experimental capacity at pH = 6 of 92 mg g−1 for an extraction time of 4 h. • Quantitative stripping is possible using (NH 4) 2 C 2 O 4 and reusability is possible for up to at least 5 cycles. [ABSTRACT FROM AUTHOR]

This work describes a new synthesis method for core–shell magnetite nanoparticles with a secondary silica shell, functionalized with a linker system (Fe3O4-PABA-SiO2-linker) using a microwave-assisted heating technique. The functionalized solid nanomaterial was used for the nanophase synthesis of peptides (Fmoc route) as a solid support. The co-precipitation method was selected to obtain magnetite nanoparticles and sol–gel technique for silica coating using a microwave-assisted (MW) procedure. The magnetic properties of the nanoparticle core offer the advantage of a quick and easy alternative for the magnetic separation of the product from the reaction mixture, facilitating all the intermediary washing and separation operations. The intermediate and final materials were analyzed by advanced characterization methods. The effectiveness of the nanophase peptide synthesis using this nanostructured material as solid support was demonstrated for a short peptide sequence. [ABSTRACT FROM AUTHOR]

A magnetoelastic (ME) biosensor for wireless detection of analytes in liquid is described. The ME biosensor was tested against human IgG in the range 0–20 μg∙mL−1. The sensing elements, anti-human IgG produced in goat, were immobilized on the surface of the sensor by using a recently introduced photochemical immobilization technique (PIT), whereas a new amplification protocol exploiting gold coated magnetic nanoparticles (core-shell nanoparticles) is demonstrated to significantly enhance the sensitivity. The gold nanoflowers grown on the magnetic core allowed us to tether anti-human IgG to the nanoparticles to exploit the sandwich detection scheme. The experimental results show that the 6 mm × 1 mm × 30 μm ME biosensor with an amplification protocol that uses magnetic nanoparticles has a limit of detection (LOD) lower than 1 nM, works well in water, and has a rapid response time of few minutes. Therefore, the ME biosensor is very promising for real-time wireless detection of pathogens in liquids and for real life diagnostic purpose. [ABSTRACT FROM AUTHOR]

• A new class microwave absorption coating was prepared by spraying method. • It showed robust microwave absorption properties under various damage environments. • It showed wide absorption bandwidth (ca.9.2 GHz). A new class microwave absorption coating based on assemblies of core-shell magnetic nanoparticles was facile preparation to improve absorption bandwidth and durability. The microwave absorption coating with a thickness of ca.1.5mm exhibited a wide bandwidth (ca.9.2GHz). Furthermore, the durability of microwave absorption coating was further evaluated. It showed good water-shedding ability and mechanical stability. The excellent performance was mainly attributed to special surface rough structure and low surface energy of coating, resulting from assemblies of core-shell magnetic nanoparticles. These provide a new idea to design and preparation of microwave absorption coating with high performance for application in stealth technology. [ABSTRACT FROM AUTHOR]

Background. Cerium oxide nanoparticles present the mimetic activity of superoxide dismutase, being able to inactivate the excess of reactive oxygen species (ROS) correlated with a large number of pathologies, such as stents restenosis and the occurrence of genetic mutations that can cause cancer. This study presents the synthesis and biological characterisation of nanoconjugates based on nanoparticles of iron oxide interconnected with cerium oxide conjugates. Methods. The synthesis of magnetite-nanoceria nanoconjugates has been done in several stages, where the key to the process is the coating of nanoparticles with polyethyleneimine and its chemical activation-reticulation with glutaraldehyde. The nanoconjugates are characterised by several techniques, and the antioxidant activity was evaluated in vitro and in vivo. Results. Iron oxide nanoparticles interconnected with cerium oxide nanoparticles were obtained, having an average diameter of 8 nm. Nanoconjugates prove to possess superparamagnetic properties and the saturation magnetisation varies with the addition of diamagnetic components in the system, remaining within the limits of biomedical applications. In vitro free-radical scavenging properties of nanoceria are improved after the coating of nanoparticles with polyethylenimine and conjugation with magnetite nanoparticles. In vivo studies reveal increased antioxidant activity in all organs and fluids collected from mice, which demonstrates the ability of the nanoconjugates to reduce oxidative stress. Conclusion. Nanoconjugates possess magnetic properties, being able to scavenge free radicals, reducing the oxidative stress. The combination of the two properties mentioned above makes them excellent candidates for theranostic applications. [ABSTRACT FROM AUTHOR]

Surface functionalization of human red blood cells (hRBCs) with fluorescent and magnetic silica core-shell nanoparticles is used to design a carrier suitable for multimodal imaging with a long circulating time. The coated magnetic hRBCs show no hemolytic activity, while the advantage of the affinity of proteins for silica allows a further coating., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)