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The utilization of nanoparticles to enhance bacterial activity and boost hydrogen production in fermentation processes has gained significant attention due to their unique properties such as high specific surface area and quantum size. This research aimed to improve the biohydrogen yield from food waste by adding iron oxide nanoparticles (Fe 3 O 4) at various concentrations (50, 75, 100, 150, and 200 mg/l) and titanium dioxide (TiO 2) at different amounts (25–150 mg/l) to a single-stage hybrid (dark/photo) fermentation reactor. After obtaining the optimal amount of these two nanoparticles, the effect of synergic addition of nanoparticles on hydrogen production yield, was investigated at ratios of Fe 3 O 4 /TiO 2 = 50/50 and 100/50 mg/mg. At the ratio of Fe 3 O 4 /TiO 2 = 100/50, the cumulative hydrogen production and yield of hydrogen have increased from 1613 to 3392 ml and 101.60 to 213.66 mlH 2 /gVS, respectively, compared to the control experiment. We also found that the COD removal rate has enhanced from 28% to 40.1%. In the optimal value, the bacterial growth lag phase has also remarkably decreased from 8.19 to 4.81 h. • Synergic application of TiO 2 and Fe 3 O 4 significantly increased biohydrogen purity and production yield. • TiO 2 played an important role in the activity of bacteria in the photo fermentation process. • Fe 3 O 4 played an important role in the dark fermentation system. • Nanoparticles may act as a scaffold for enzyme and substrate binding. • Optimal nanoparticle concentration may differ for different bioreactors. [ABSTRACT FROM AUTHOR]

An advanced version of the solution combustion synthesis (SCS) method was developed to prepare iron oxide (IO) nanoparticles, through controlling the agglomeration, size and shape of nanoparticles by assisting a cationic surfactant, "cetyltrimethylammonium bromide (CTAB)" and ethanol. Various IO nanoparticles were prepared in the presence of different CTAB:ethanol molar compositions of 0:0, 0.27:0, 0.55:0, 0.27:17.1, 0.55:17.1 and 0.82:17.1. The morphological evolution from agglomerated-shape particles to the well-dispersed as well as the size- and shape-controlled particles depended directly on the CTAB:ethanol molar composition. A shift from ferromagnetic behavior to superparamagnetic was observed by the application of CTAB along with ethanol, where the lowest blocking temperature (T b , 60 K), highest saturation magnetization (M s , 83.5 emu g−1), zero coercivity and remanance magnetization were revealed for the particles prepared by CTAB:ethanol molar compositions of 0.55:17.1. These particles showed an acceptable specific absorption rate (SAR) value (320 W g−1) as well as no obvious hemolytic and cytotoxic effects. This work provides new insights into advancing the SCS method and thus controlling the morphology, size and shape of metal oxide nanoparticles. [Display omitted] • Controlling the agglomeration, size and shape of nanoparticles in SCS method. • Structural and magnetic properties of particles depended on the CTAB:ethanol ratio. • The agglomerated-free, size- and shape-controlled IO-EC2 structure was developed. • IO-EC2 represented an acceptable SAR value, and no hemolytic and cytotoxic effects. [ABSTRACT FROM AUTHOR]

Multicore magnetic iron oxide nanoparticles, nanoflowers (NFs), have potential biomedical applications as efficient mediators for AC-magnetic field hyperthermia and as contrast agents for magnetic resonance imaging due to their strong magnetic responses arising from complex internal magnetic ordering. To realise these applications amenable surface chemistry must be engineered that maintain particle dispersion. Here a catechol-derived grafting approach is described to strongly bind polyethylene glycol (PEG) to NFs and provide stable hydrogen-bonded hydrated layers that ensure good long-term colloidal stability in buffers and media even at clinical MRI field strength and high concentration. The approach enables the first comprehensive study into the MRI (relaxivity) and hyperthermic (SAR) efficiencies of fully dispersed NFs. The predominant role of internal magnetisation dynamics in providing high relaxivity and SAR is confirmed, and it is shown that these properties are unaffected by PEG molecular weight or corona formation in biological environments. This result is in contrast to traditional single core nanoparticles which have significantly reduced SAR and relaxivity upon PEGylation and on corona formation, attributed to reduced Brownian contributions and weaker NP solvent interactions. The PEGylated NF suspensions described here exhibit usable blood circulation times and promising retention of relaxivity in-vivo due to the strongly anchored PEG layer. This approach to biomaterials design addresses the challenge of maintaining magnetic efficiency of magnetic nanoparticles in-vivo for applications as theragnostic agents. Application of multicore magnetic iron-oxide nanoflowers (NFs) as efficient mediators for AC-field hyperthermia and as contrast agents for MR imaging has been limited by lack of colloidal stability in complex media and biosystems. The optimized materials design presented is shown to reproducibly provide PEG grafted NF suspensions of exceptional colloidal stability in buffers and complex media, with significant hyperthermic and MRI utility which is unaffected by PEG length, anchoring group or bio-molecular adsorption. Deposition in the selected pancreatic tumour model mirrors liposomal formulations providing a quantifiable probe of tissue-level liposome deposition and relaxivity is retained in the tumour microenvironment. Hence the biomaterials design addresses the longstanding challenges of maintaining the in vivo magnetic efficiency of nanoparticles as theragnostic agents. [Display omitted] [ABSTRACT FROM AUTHOR]

Oxide materials are important for gas sensing applications. Unfortunately, most of the synthesis methods use many toxic chemicals and need long calcination at high temperatures. Thus, developing simple and green synthesis processes, which can be performed fast and at low temperatures, is imperative for both industrial manufacturers and our environment. Here, our fast and green synthesis method based on low-power laser sintering for producing FeO x (with Fe 2 O 3 as the main composition) is presented. Besides, FeO x particles were decorated on reduced graphene oxide (RGO) to form a resistive sensor. Notably, our FeO x material can reduce the response of RGO toward acidic gas (NO 2) but it enhances the RGO response toward the basic NH 3 gas. Particularly, our hybrid FeO x /RGO sensor can detect NH 3 gas at above 2 ppm under dry and humidified conditions (<85 % RH). That effect of FeO x is found due to the formation of alpha-phase Fe 2 O 3 which acts as a p-type semiconductor, which is explored and explained in the discussion section. Finally, our findings not only reveal the potential of our hybrid sensing materials for practical NH 3 sensing applications but also confirm the usefulness of laser-sintering to produce catalytic oxide materials environmentally friendly and at low cost. [Display omitted] • Fast and green production method of iron oxides (Fe 3 O 4 or Fe 2 O 3) is reported. • FeO x was directly formed on RGO resistive gas sensors via laser sintering. • p-type FeO x tuned the sensing behavior of RGO materials toward NH 3 basic gas. • The hybrid FeO x /RGO sensor can work at RT and under a wide humidity range. [ABSTRACT FROM AUTHOR]

Nanofluid-based direct absorption of solar heat results in thermal efficiencies superior to conventional solar thermal technology. In addition, convection of nanofluid can be sustained pump-free in the collector. In this article, we study an aqueous magnetic nanofluid capable to establish the photothermal convection in a lab-scale direct absorption solar collector equipped with a solenoid. The nanofluid consisted of 60-nm Fe 2 O 3 particles dispersed in distilled water at concentration in the range 0.5% wt.-2.0% wt. An empirical model of the photothermal convection was developed based on the experiments. The model accounted for magnetic and thermophoretic forces acting within the nanofluid. The nanofluid with up to 2.0% wt. iron oxide nanoparticles obtained the velocity of ∼ 5 mm/s under the magnetic field of up to 28 mT. This resulted in the maximum thermal efficiency of the collector equal to 65%. [Display omitted] • Nanofluid-based direct absorption solar collector is studied. • Nanofluid is produced with 0.5% and 2.0% of Fe 2 O 3 nanoparticles. • Magnetic field up to 28 mT is applied to nanofluid. • Photothermal convection is established in the fluid with the velocity of 2-5 mm/s. • Maximum thermal efficiency of the collector is 65%. [ABSTRACT FROM AUTHOR]

[Display omitted] • In situ iron oxide nanoparticles were synthesized into heavy crude oil. • Magnetite and akaganeite nanoparticles in situ presented sizes of 20–43 nm. • Reaction conditions were at 200 nm3/m3 of H 2 /heavy crude oil ratio, 380 °C and 1 h. • Residue conversion was approximately 20 %. • Spent catalyst showed the iron sulfide phase, although no presulfiding was realized. We proposed a direct in situ synthesis method for iron oxide nanoparticles (NPs) along with catalytic erformance upgrading of heavy crude oil (HCO). Our method compares the upgrading of a HCO where other iron oxide nanoparticles were synthesized by a traditional thermal decomposition method of organometallic compounds in the presence of stabilizing agents and solvents of high boiling points. Furthermore, the in situ nanoparticles were extensively characterized by XRD, Mössbauer spectroscopy and TEM microscopy which confirmed the presence of magnetite and akaganeite phases, with an average diameter of 20−43 nm. Nanoparticles by thermal decomposition method were investigated by XRD, UHR-FE-SEM and HRTEM and showed the formation of magnetite nanoparticles with an average diameter of 6.7 ± 1.4 nm. Subsequently, the nanoparticles were evaluated in a batch reactor using HCO from the Golden Lane of Mexico at 44.1 bar (initial H 2 pressure) and 380 °C, for 1 h at 500 rpm. It was observed that, even under hydrogen limited conditions, there are better physicochemical properties in terms of viscosity, API gravity and heavy fractions decrease, for example, the residue conversion was about 20 % and the kinetic model was adjusted to a five lump model. The formation of the iron sulfide phase (FeS) was detected during the analysis of the spent catalyst. [ABSTRACT FROM AUTHOR]

Controlled spatial arrangements of superparamagnetic iron oxide nanoparticles (SPIONs) in complex nanostructures determine fine tuning of physico-chemical properties which, in turn, may lead to new practical applications. We report here on newly observed properties of hierarchical SPIONs nanostructure with bundle-like morphology, also known as nanobundles. Colloidal chemical processes and sol-gel synthesis were used for the synthesis of nanobundles, i.e. i) self-assembly of SPIONs into magnetic nanoparticle clusters, ii) their magnetic assembly to the nanochains, and finally iii) formation of bundle-like hierarchical nanostructure. An XRPD measurements show spinel crystal structure of maghemite/magnetite nanoparticles, EDS analysis reveals Fe, Si and O as main elements whereas SEM/TEM analysis show silica-coated magnetic nanoclusters (∼100 nm) and their hierarchical assemblies with bundle-like morphology of ∼8 μm length and ∼1 μm width. TEM analysis revealed core-shell nature of iron oxide nanoparticle clusters with their size of around 80 nm that were coated by an amorphous silica shell with thickness of ∼15 nm. The nanoclusters in the core are constructed of maghemite/magnetite nanoparticle assembly with primary iron oxide nanoparticle size about 10 nm. The magnetization M data as a function of an applied external magnetic field H were successfully fitted by the Langevin function, whence the magnetic moment μ p = 19256 μ B , and the diameter d = 9.6 nm of nanoparticles were determined. Microsized bundle-like particles are superparamagnetic, magnetically guidable and possess high transverse relaxivity of r 2 = 397.8 mM−1s−1. Magnetic properties and such high value of transverse relaxivity holds promise for nanobundles application in MRI imaging (MRI contrast agent), as nanobundles may enhance the magnetic field in their surroundings and enhance proton relaxation processes. Our nanobundles can open new opportunities in the biomedical applications, magnetic separation, photonic crystals and magnetic liquid manipulation and can be inspiration for synthesizing novel self-assembled nanoparticle structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanocomposites based on graphene nanoribbons and iron oxide nanoparticles were synthesized by varying the particle size. • Properties such as specific surface area, magnetic response and specific capacitance were investigated as a function of the particle size. • All the properties studied were strongly affected by the particle size. • Nanocomposites with a high specific surface area can be obtained by tuning the particle size. • The specific capacitance of the nanocomposites is increased with the specific surface area. The particle size effect on nanocomposites made of reduced graphene nanoribbons (GNRs) and iron oxide nanoparticles (IONPs) is studied. Three nanocomposites with different particle size were prepared by chemical reduction of IONPs formed by the co-precipitation method on graphene oxide nanoribbons. Several experimental techniques such as transmission electron microscopy, selected area electron diffraction and X-ray diffraction determined the particle size distribution and crystalline phases present in the samples. The specific surface area (SSA) of the nanocomposites was measured and discussed with the mean size of the IONPs. Depending on the mean size and surface distribution of the IONPs, samples with high SSA can be achieved. Magnetic measurements indicated that the particle size affects the magnetic properties of the nanocomposites. These results were discussed considering the effect of particle size, defects, amount of particles and interaction between the IONPs and GNRs surface. The potential application of the samples as supercapacitors was evaluated by calculating their specific capacitance from cyclic voltammetry measurements. The results showed that the specific capacitance increases with the SSA. This work confirms that the size of the IONPs significantly affects the properties of the nanocomposites, specifically the SSA, which is of great interest for various applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • VFAs can be obtained from an aqueous solution derived by the fermentation of food waste; • Their recovery is pivotal for economic and environmental reasons; • Iron oxide NPs with functionalization or not showed low reproducible results; • Liquid-liquid extraction can be used showing higher efficiency; • the use of oleic acid presented extraction capacity up to 97% and good reproducibility. The extraction of volatile fatty acids (VFAs) from an aqueous solution derived by fermentation of food waste is a key challenge in the context of the circular economy, thanks to their high economic and environmental impact due to their wide-ranging use in various industrial fields. In this work, we compared two different extraction methods: one novel and one classical. Firstly, iron oxide nanoparticles of around 10 nm were prepared and used as they are or functionalised using (3-Aminopropyl)triethoxysilane) (APTES) molecules, adipic acid and oleic acid. This was compared with a traditional industrial method (liquid–liquid extraction) that can guarantee high extraction of VFAs with high reproducibility. Indeed the use of dichloromethane, hexane, methyl tert -butyl ether and oleic acid presented extraction values of up to 30 % while iron oxide NPs showed results with low reproducibility. The comparison demonstrated the use of oleic acid as a promising solvent for liquid–liquid extraction of VFAs. [ABSTRACT FROM AUTHOR]

Flexible supercapacitors (SCs) are pivotal in the development of wearable and portable electronic devices because of their exceptional power density, high charge/discharge rates, extended cycle life, lightweight, and flexibility. Graphene (G)-based macroscopic materials, such as one-dimensional fibers, two-dimensional films, and three-dimensional aerogels, exhibit a large specific surface area, low mass, excellent flexibility, and high conductivity. These properties make them highly suitable for use as flexible electrode materials in SCs. However, the low energy density of G-based materials hinders their application in certain fields. Iron oxide (Fe 2 O 3) has garnered considerable attention as a negative electrode material because of its low cost, high theoretical capacity, and environmentally friendly nature. However, its practical application is limited because of its poor cycling stability, easy agglomeration, and low electrical conductivity. The combination of G with Fe 2 O 3 to form a composite material not only addresses the issues of volume change and agglomeration associated with Fe 2 O 3 , but also establishes a robust conductive network that improves the electrochemical performance of composite electrodes. Therefore, the construction of SCs using Fe 2 O 3 /G composite electrodes has gained considerable research attention in recent years. We present a comprehensive review of the recent progress in the design of Fe 2 O 3 /G composites as electrode materials for flexible SCs. In addition, we discuss the current challenges and future prospects associated with the use of Fe 2 O 3 /G composites in flexible SCs. [Display omitted] • Recent progress in the design of iron oxide/graphene composites as electrode materials for flexible SCs is reviewed. • The fabrication methods are discussed in depth to provide insight into various development strategies. • The design strategies of iron oxide/graphene composites with different dimensions were comprehensively discussed. • Challenges in iron oxide/graphene composites-based flexible supercapacitors development were described. [ABSTRACT FROM AUTHOR]

In recent years, suitable bioactive materials coated nanoparticles have attracted substantial attention in the field of biomedical applications. The present study emphasizes experimental details for the synthesis of boiling rice starch extract (BRE) coated iron oxide nanoparticles (IONPs) to treat cancer by photoacoustic imaging (PAI)-guided chemo-photothermal therapy. The solvothermal method was used to synthesize IONPs. The physical immobilization method helps to coat BRE-loaded doxorubicin (DOX) molecules on the iron oxide surface. In vitro drug release was estimated in basic (pH 9.0), neutral (pH 7.2), and acidic (pH 4.5) media for varying time periods using ultraviolet-visible spectroscopy. The chemical and physical properties of the synthesized spherical BRE-IONPs were characterized using sophisticated analytical instrumentation. A magnetic saturation experiment was performed with BRE-IONPs for evaluating possible hyperthermia in targeted drug delivery. The biological activity of the synthesized BRE-IONPs was investigated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and acridine orange/propidium iodide fluorescence cell viability study. BRE-IONPs showed excellent photothermal stability, with a high photothermal conversion efficiency (η = 29.73%), biocompatible property, and high near-infrared region absorption for PAI-guided PTT treatment. This study will provide a better understanding of rice starch as a suitable bioactive coating material for possible theranostic applications. • A facile synthesis technique of natural polymer boiling rice extract-coated IONPs is studied for biomedical applications. • The drug loading (~78% DOX) with pH regulated releasing property (~46% DOX) makes DOX-BRE-IONPs a promising anticancer agent. • The synthesized DOX-BRE-IONPs acts as an excellent photothermal agent with a heat conversion efficiency of ~29.73%. • DOX-BRE-IONPs have potential photoacoustic imaging contrast efficiency for bio-imaging applications. • DOX-BRE-IONPs could be a promising multifunctional imaging-guided chemo-photo-thermal therapeutic agent for cancer treatment. [ABSTRACT FROM AUTHOR]

Salt-assisted solution combustion synthesis (SSCS) method is a promising technique for synthesizing various nanopowders with ultra-fine particle size and high surface area. It is known that the introduced soluble salt into the synthesis process plays a role as a particle separator which leads to the particle size reduction. However, the potential effects of soluble salts on the thermodynamic aspects of SSCS procedure and the other physical and chemical properties of the obtained nanopowders have not been investigated in detail. In this study, various amounts of sodium chloride (1–15mol for obtaining 0.3mol iron oxide) were introduced to the iron nitrate-glycine system to investigate effect of alkali metal salt on the thermodynamics aspects of the synthesis process and the final properties of the prepared nanoparticles. Obtained results indicated that the phase composition of the synthesized nanopowders was varied from a mixture of Fe 3 O 4 +α-Fe 2 O 3 to γ-Fe 2 O 3 +α-Fe 2 O 3 , and eventually to single-phase α-Fe 2 O 3 by increasing the amount of sodium chloride. Such phase transformation suggested that the phase composition of multi-phase compounds prepared via SSCS method can be controlled by sodium chloride. Ultra-fine powders with 9 nm particle size and surface area of 148 m2/g were obtained when 11mol sodium chloride was used in the synthesis process. Magnetization of the synthesized nanoparticles were decreased from 34emu/g to 2.7emu/g due to the decrement of particle size. The combusted single-phase hematite nanopowders were submitted to the 100 mL nickel ion (Ni2+) solution with the ion concentration of 50 mg/L to explore the effect of salt on the adsorption activity of the nanoparticles. 0.4g of the synthesized powders adsorbed ~ 90% of the nickel ions within 120 min. Note that the removal percentage of the nickel ion using the synthesized hematite nanoparticle (90%) was higher than that of prepared hematite powders in the previous studies (35%). [ABSTRACT FROM AUTHOR]

In this work, a novel organic–inorganic hybrid heterogeneous catalyst was fabricated for Knoevenagel condensation. First, the surface of carbon nanotube (CNT) was covalently functionalized with poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) polyelectrolyte (i.e., organic polybase) through the surface-initiated atom transfer radical polymerization (SI-ATRP) method. Subsequently, magnetic iron oxide nanoparticles (Fe 3 O 4 NPs) (i.e., inorganic Lewis acid) are densely and homogeneously grown on the CNT surface using the CNT- g -PDMAEMA template. The as-prepared acid–base bifunctional catalyst (i.e., CNT- g -PDMAEMA/Fe 3 O 4 NPs) was investigated in the model reaction, i.e., Knoevenagel condensation between naphthol, malononitrile and benzaldehyde. The CNT- g -PDMAEMA/Fe 3 O 4 NPs catalyst shows high catalytic activity in the Knoevenagel condensation between naphthol, malononitrile and benzaldehyde due to its unique structure and specific chemical constitution. In addition, this acid–base bifunctional catalyst can be readily recovered with an applied magnetic field and reused with negligible loss in the catalytic activity even after six cycles. [Display omitted] • The acid–base bifunctional CNT- g -PDMAEMA/Fe 3 O 4 NPs catalyst exhibited high activity. • The tiny Fe 3 O 4 NPs on the CNT as acid catalyst can activate the benzaldehyde. • The rich PDMAEMA brushes on the CNT as base catalyst may activate the malononitrile. • One-pot synthesis of 2‐amino‐4 H‐chromene product was achieved under green condition. • The magnetic CNT- g -PDMAEMA/Fe 3 O 4 NPs was a reusable catalyst with ease of separation. [ABSTRACT FROM AUTHOR]

Hybrid polyion complexes (HPICs) obtained from the complexation in aqueous solution of a double hydrophilic block copolymers and metal ions can act as efficient precursors for the controlled synthesis of hybrid nanoparticles. Hence, HPICs based on a mixture of ferrous and ferric ions with poly(ethylene oxide)-block-poly(acrylic acid) were used to initiate, after the addition at 70 °C of a solution of NH 4 OH, the formation of iron oxide nanoparticles. The careful choice of the molar ratio between polymer and metal ions within HPICs enables to tune the morphology and size of the obtained iron oxide nanoparticles while maintaining the same surface composition. This control of size and composition was further used to highlight the relationship between the size of these particles and their catalytic and magnetic properties. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Glucose non-enzymatic electrochemical sensor based on polyaniline, graphene and MOF. • A large surface area, enhanced electron transfer and catalytic properties. • The sensor has a wide linear range and good sensitivity. • Acceptable performance in human fluids real samples including serum and plasma. In this study, a novel highly sensitive and selective non-enzymatic glucose sensor was fabricated by coating simple and cheap graphite sheet (GS) electrodes with a proper conductive nanocomposite containing nitrogen-doped functionalized graphene (NFG), conductive polyaniline (PANI), and core–shell nanoparticles (Fe 3 O 4 @MIL-101-NH 2). The results revealed that the core centers of iron oxide nanoparticles shelled by MIL-101-NH 2 enhanced the electron transfer and led to more conductivity, also their existence caused the limitation of the MOF's low conductivity. In addition, using Fe 3 O 4 @MIL-101-NH 2 in the nanocomposite structure led to more sensitivity and selectivity at glucose monitoring due to its amine groups and unique structure. The results showed that NFG/PANI/Fe 3 O 4 @MIL-101-NH 2 nanocomposite provided a large surface area besides enhanced electron transfer and catalytic properties that lead to proper oxidation of glucose with two linear ranges of 0.5 – 10 µM and 100 µM – 25 mM and a low detection limit of 0.3 µM (S/N = 3). Furthermore, the relative standard deviation (RSD%) in all detection processes was lower than 9 %. Finally, the performance of fabricated non-enzymatic sensor (GS/NFG/PANI/Fe 3 O 4 @MIL-101-NH 2) in human fluids real samples including serum and plasma was acceptable which significantly indicates that it is toward monitoring of glucose in clinical applications. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles in general, and iron oxide nanoparticles in particular, have been studied extensively during the past 20 years for numerous biomedical applications. The main applications of these nanoparticles are in magnetic resonance imaging (MRI), magnetic targeting, gene and drug delivery, magnetic hyperthermia for tumor treatment, and manipulation of the immune system by macrophage polarization for cancer treatment. Recently, considerable attention has been paid to magnetic particle imaging (MPI) because of its better sensitivity compared to MRI. In recent years, MRI and MPI have been combined as a dual or multimodal imaging method to enhance the signal in the brain for the early detection and treatment of brain pathologies. Because magnetic and iron oxide nanoparticles are so diverse and can be used in multiple applications such as imaging or therapy, they have attractive features for brain delivery. However, the greatest limitations for the use of MRI/MPI for imaging and treatment are in brain delivery, with one of these limitations being the brain-blood barrier (BBB). This review addresses the current status, chemical compositions, advantages and disadvantages, toxicity and most importantly the future directions for the delivery of iron oxide based substances across the blood-brain barrier for targeting, imaging and therapy of primary and metastatic tumors of the brain. Magnetic forces could be used in the controlled delivery of injected magnetic iron oxide nanoparticles (IONPs) for imaging, targeting and treatment of brain tumors. Unlabelled Image [ABSTRACT FROM AUTHOR]

• A multiscale modeling framework for fluidized bed reactors is presented. • Chemical looping reforming reactor employing iron oxide nanoparticles is modelled. • Kinetic Monte Carlo simulations provide rates of surface chemistry. • Intra-particle transport model handles competing diffusion and chemical reactions. • Reactive multiphase flow is modeled by fluid-particle flow model. A multiscale modeling framework is described and applied to the reactivity of iron oxide nanoparticles in a chemical looping reforming (CLR) reactor. At the atomic scale/nanoscale, we have performed kinetic Monte Carlo modeling, guided by Density Functional Theory calculations, on the detailed kinetics of the CH 4 conversion to products as a function of temperature. These results have been post-processed for use in macroscopic models with the goal to integrate process information with materials information. Two levels of macroscopic models have been used to evaluate the performance of the nanoparticles in their final application: (1) a pore-unresolved intra-particle transport model that accounts for limitations via an effective diffusivity and an effectiveness factor, and (2) a fluid-particle multiphase flow model that allows the study of the consequences of clustering and intra-particle transport on overall reactor performance. This modeling approach ultimately leads to better descriptors of material performance that can be used in future materials screening activities. [ABSTRACT FROM AUTHOR]

The logical research on fundamentally adjusted iron oxide nanoparticles has turned out to expanded in biomedicine because of the improved activity and best biocompatibility. In this present work upgraded bio-restorative and pharmacotherapeutic property of chitosan‑iron oxide nanocomposite, which was set up by eco-friendly in situ substance technique. Characterisation of the synthesised nanocomposite by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction,(XRD) and Vibrating test magnetometer (VSM) studies reveals that highly stable spherical, electron-dense core shelled rough particles of 50-60 nm. Particle morphology of the synthesised nanocomposite utilising scanning electron microscopy (SEM) uncovers spherical; thick electron centre shelled harsh particles with the size scope of 50-60 nm. FTIR studies show that the specific interaction of practical gatherings of chitosan with iron oxide nanoparticles. Crystalline phase and magnetisation impact of the composite resolved from XRD and VSM studies. Anti-bacterial activity of the nanocomposite examined against human bacterial pathogens which suggest that the readied nanocomposite successfully restrained the development of the tried bacterial strains by recording maximum zone of inhibition, least minimum inhibition concentration (MIC) and biofilm damage against the both tested strains. 100 μg dosages of nanocomposites recorded 20.0 and 21.0 mm of the zone of inhibition against E. coli and S. aureus respectively. Biofilm restraint was additionally observed to be high in nanocomposite treatment by recording lower optical density of ethanol solubilised biofilm of both tested strains. Anticancer activity was examined against the A549 cell line by the assurance of cell feasibility as opposed to oxidative proteins, articulation example of TNF-α, Bax, PARP qualities and apoptosis. Composite prompted 50% of cytotoxicity at 80 μg/mL unmistakably uncovers cytotoxicity against A549 cells. Nanocomposite treatment revealed a high decrease of cell feasibility at all the fixation and most extreme impact seen in 100 μg. Nanocomposite treated cells demonstrated striking changes in cell morphology, the build-up of atomic material related to trademark changes in against oxidative enzymes, quality articulation design which brought about apoptosis-like necrotic cell death. The present findings would propose the conceivable usage of chitosan‑iron oxide nanocomposite as a viable remedial against safe medication pathogens and malignant growth cells. Unlabelled Image • Simple eco-friendly in situ strategy achieved exceedingly stable CS-IO nanocomposite. • Synthesised CS-IONC displayed enhanced antibacterial activity against tested bacterial strains. • Inhibition of cell viability and promoted apoptosis against A 549 cell line reveals distinct anticancer activity. [ABSTRACT FROM AUTHOR]

In this work, we report a ultrahigh specific absorption rate (SAR) performance in Zn-substituted magnetite superparamagnetic (SPM) nanoparticles (NPs) for potential application in magnetic hyperthermia (MHT)-based cancer treatment. Although MHT shows promise in cancer therapy, challenges such as low heating performance, agglomeration of magnetic nanoparticles (MNPs) in blood veins, cytotoxicity, and hemocompatibility have hindered clinical uses. To overcome these challenges, we adopted a reverse-micelles based coprecipitation synthesis approach to prevent MNPs agglomeration and optimized the substitution of Zn ions in magnetite to enhance heating performance. Calorimetric measurements showed SAR values of 118 W/g and 181 W/g for magnetite NPs using the initial slope method (ISM) and Box Lucas method (BLM), respectively. Through our compositional optimizations, we achieved a significant increase in SAR value by consciously substituting Zn2+ ions in the magnetite lattice. Specifically, we obtained SAR values of 325 W/g and 579 W/g (>300% increase) for Zn 0.3 Fe 2.7 O 4 MNPs using ISM and BLM, respectively. This enhancement can be attributed to improved saturation magnetization (174–257 kA/m) and magneto-crystalline anisotropy (12–24 kJ/m3). The increase in saturation magnetization in the magnetite MNPs can be explained by the higher magnetic moment resulting from increased Zn concentration up to Zn x Fe 3-x O 4 (x = 0.3), strengthening the J AB interaction. However, further increases in Zn concentration lead to a decrease in saturation magnetization due to non-collinearity, as described by the Yafet-Kittle model. Our optimized MNPs exhibit improved heating performance, enabling the use of lower MNPs concentrations for cancer treatment, reducing potential toxicity effects. Biocompatibility investigations demonstrated a low hemolysis rate (<5%) in a hemolysis assay with red blood cells and high cytocompatibility (>92% cell viability) in MTT assays for all compositions, confirming their potential suitability for clinical applications. This study offers a promising approach to enhance SAR performance, addressing MHT-based cancer treatment challenges, and improving clinical suitability. • Achieved 300% increase in SAR, indicating enhanced heating performance for cancer treatment. • Optimized magnetic properties through the Zn ions substitution making it suitable for magnetic hyperthermia treatment. • Demonstrated low toxicity and high biocompatibility, ensuring their suitability for clinical treatment. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H 2 O 2) is a vital messenger molecule facilitating signal transmission within cellular systems. The accurate quantification of H 2 O 2 in complex environments, such as human serum, is instrumental in elucidating its diverse biological functions. In this study, we present the development of a robust electrode platform by integrating hemoglobin onto iron oxide (Fe 3 O 4) nanoparticles and reduced graphene oxide (rGO) as a conducting support for the sensitive detection of H 2 O 2 in human serum. The Fe 3 O 4 /rGO nanocomposite was synthesized via a facile single-step thermolysis reaction in the presence of oleylamine. Transmission electron microscopy (TEM) analysis revealed the formation of highly monodisperse Fe 3 O 4 nanoparticles that were uniformly dispersed over the reduced graphene surface. The rGO surface provided abundant active sites (Fe 3 O 4) for H 2 O 2 sensing. Consequently, the resulting Hb/Fe 3 O 4 @rGO modified electrode exhibited a wide linear range of H 2 O 2 concentrations from 1.5 to 2684 µM, demonstrating high sensitivity and low detection limit. Further characterization of the Hb/Fe 3 O 4 @rGO/GC electrode revealed a high surface coverage (τ = 3.0 × 10−9 mol cm−2), charge transfer coefficient (α = 0.83), and electron transfer rate constant (k s = 1.33 s−1). Subsequently, the Hb/Fe 3 O 4 @rGO/GC sensor probe was employed to analyze H 2 O 2 in real human serum samples, demonstrating excellent recovery rates ranging from 99.8 % to 104.0 %. The nanocomposite material, designed through the innovative combination of graphene oxide reduction, Fe 3 O 4 nanoparticle decoration, and oleylamine amide/amine bonding, serves as an excellent electrode material for H 2 O 2 concentration sensing. Thus, this study presents a promising platform for the future determination of H 2 O 2 biomarkers in clinical settings. [Display omitted] [ABSTRACT FROM AUTHOR]

• Iron oxide nanoparticles recovered from the acid mine drainage treatment are suitable to produce nanofluids. • Iron oxide nanoparticles in concentration 0.10–0.75 wt% can be used to produce stable nanofluids. • Additional 7–10% oil recovery is achieved after flooding due to injection of iron oxide-based nanofluids. Oil is one of the most intensively used energy sources in the world and, as a fossil fuel, it is a finite resource. Different methods have been explored to increase oil recovery from mature fields, particularly using enhanced oil recovery (EOR) with the help of nanofluids. This study performed EOR tests using iron oxide nanoparticles added to brine and sodium dodecyl sulfate solutions. Three types of iron oxide nanoparticles were examined: commercial (IO), derived from the acid drainage of an underground coal mine (SIO), and temperature-sensitive functionalized (TSIO). The nanoparticles were well characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, high-resolution X-ray photoelectron spectroscopy, and transmission electron microscopy. The nanofluids were evaluated through dynamic light scattering measurements and determination of the viscosity, turbidity, contact angle and surface tension. There was not significant variation in the surface tension of the samples, which ranged between 25.46 and 28.28 mN m−1. However, the contact angle exhibited notable fluctuations depending on the nanoparticles concentration, ranging from 7.39° to 24.43°. Furthermore, the zeta potential suggests that the stability of the nanofluid samples falls within the moderate to medium range. An improvement in oil recovery reached 10% with the commercial nanoparticles (0.50 wt%), followed by 8.5% using the synthesized (0.25 wt%) and 7.5% using the functionalized (0.25 wt%). Moreover, all nanofluids showed good stability for up to 30 days, and their viscosity showed a direct relationship with the enhancement in oil recovery. [ABSTRACT FROM AUTHOR]

• Experiments are performed in both CSS and MSS at different water depths in coated and uncoated absorber. • Increase in water depth decreases the fresh water generation from both cases. • The fresh water produced from CSS and MSS are 3.85 and 6.03 kg/m2 respectively. • The thermal and exergy efficiencies are found as 47.67 and 4.53 % respectively using the MSS. • CPL of fresh water produced is lowered by 29.96 % than the SS using uncoated absorber. The quantity of drinkable water that is easily accessible is dwindling at an extremely quick pace. An extra degree of complication has been added to the problem as a consequence of the depletion of freshwater resources brought on by human activities. The primary objective of the present study is to enhance the rate of fresh water generation through the low-cost solar desalination unit using iron oxide as coating material using different thickness of water placed in the absorber plate. The experimental results revealed that the influence of metal oxide nanoparticle as absorber coating material improved the rate of fresh water generation by 36.08 % than the conventional solar still at a minimum thickness of water as 1 cm in the absorber. The palatable fresh water generated from the SS without any absorber coating for the thickness of water as 10, 20 and 30 mm is found to be 3.85, 3.09 and 2.90 kg/m2 respectively. However, with effective coating of the absorber plate using Fe 2 O 3 nanoparticle, the cumulative daily palatable water generated from the solar still for different thickness of water as 10, 20 and 30 mm is enhanced to about 6.03, 5.36 and 4.72 kg/m2 respectively. There is a significant enhancement of about 38.47 to 60.15 % and 1.96 to 4.53 % in the daily energy, and exergy efficiencies of the solar still using coated absorber plate in the SS respectively while compared to the SS using uncoated absorber at the lowest thickness of water in the absorber of basin. Similarly, the CPL of fresh water produced from the SS using coated absorber is lowered by 29.96 % than the SS using uncoated absorber. [Display omitted] [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles based on Fe 3 O 4 and their modifications of surface with therapeutic substances are of great interest, especially drug delivery for cancer therapy includes boron-neutron capture therapy. The results of boron-rich compound (carborane borate) attachment to previously aminated by (3-aminopropyl)-trimethoxysilane iron oxide nanoparticles are presented. Energy-dispersive X-ray analysis and Fourier transform infrared spectroscopy with attenuated total reflection (ATR) accessory confirmed change of nanoparticles elemental content after modification and formation of new bond between Fe 3 O 4 and attached molecules. Scanning and transmission electron microscopy showed that Fe 3 O 4 nanoparticles average size is 18.9 nm. Phase parameters were investigated by powder X-ray diffraction, Fe 3 O 4 nanoparticles magnetic behavior was evaluated by Mössbauer spectroscopy. Chemical and colloidal stability was studied using simulated body fluid (phosphate buffer – PBS). Modified nanoparticles have excellent stability in PBS (pH = 7.4), characterized by X-ray diffraction, Mössbauer spectroscopy and dynamic light scattering. Fe 3 O 4 biocompatibility was elucidated in-vitro using cultured mouse embryonic fibroblasts. The obtained results show the increasing of IC 50 from 0.110 mg/ml for Fe 3 O 4 to 0.405 mg/ml for Fe 3 O 4 -Carborane nanoparticles. Obtained data confirm biocompatibility and stability of synthesized nanoparticles and potential to use them in boron-neutron capture therapy. • Fe 3 O 4 nanoparticles (NPs) with 18.9 nm average size were synthesized and modified with APTMS. • NPs were characterized using FTIR, SEM, TEM, XRD, DLS, Mössbauer spectroscopy and VSM methods. • Modified NPs have excellent stability in simulated body fluid. • Carborane borate with 21 boron atoms was immobilized on NPs through the ionic interaction. • Synthesized modifed NPs are excellent candidates for using in boron-neutron capture therapy. [ABSTRACT FROM AUTHOR]

Design of a multifunctional magnetic bionanosystem has become increasingly important towards advancing the future of clinical medicine. While hollow iron oxide nanoparticles with enhanced surface areas allow for more drug molecules to be attached to the particles, their relatively low saturation magnetization (M S) hinders their practicality in medicinal applications such as drug delivery and hyperthermia therapy. We demonstrate that this limitation can be overcome by utilizing 1D magnetic nanotubes that possess both enhanced surface areas and high M S. In this study, highly crystalline, tunable aspect ratio Fe 3 O 4 nanotubes have been successfully synthesized using a hydrothermal method. Magnetic measurements showed a clear Verwey transition (∼120 K) and high M S (∼75 emu/g) at 300 K, confirming the high quality of the synthesized Fe 3 O 4 nanotubes. Calorimetric experiments on randomly dispersed Fe 3 O 4 nanotubes in water with concentration of 1 mg/mL showed a large Specific Absorption Rate (SAR) value of 400 W/g for an AC magnetic field of 800 Oe, which increased to 500 W/g when the nanotubes were aligned parallel to the DC magnetic field and suspended in a 2% agar solution. Our study shows the possibility of using the Fe 3 O 4 nanotubes as a highly effective multifunctional nanoscale tool for targeted hyperthermia and on-demand drug delivery. • Hydrothermal synthesis of highly crystalline, tunable aspect ratio Fe 3 O 4 nanotubes. • Systematic study of the growth mechanism of the nanotubes. • The presence of Verwey transition and high M S (75 emu/g) at 300 K. • Nanotubes exhibited large SAR value compared to their hollow counterparts. • Dual-purpose applications in hyperthermia and on-demand drug delivery. [ABSTRACT FROM AUTHOR]

Abstract This article describes the synthesis, characterization and in vivo cytotoxic evaluation of thiol-functionalized superparamagnetic iron oxide magnetic nanoparticles (SPIONs). They have been employed as potential vehicles for a large number of biomedical applications, such as drug delivery. Fe 3 O 4 nanoparticles were synthesized by coprecipitation of iron salts and coated with L-cysteine. The physicochemical, morphological, and magnetic properties of Cys-Fe 3 O 4 nanoparticles were characterized by different experimental techniques. To evaluate their applicability in nanomedicine we evaluated their cytotoxicity using Balb/C mice. The results show that Cys-SPIONs are good candidates as nanocarriers in biomedical applications. Graphical abstract Unlabelled Image Highlights • Cys-Fe3O4 shows superparamagnetic behavior at room temperature. • Cys-Fe3O4 NPs show good colloidal stability. • Successful application of Cys-Fe3O4 as a biocompatible carrier in in vivo assays • The NPs do not interfere in ferric homeostasis. [ABSTRACT FROM AUTHOR]

Influenza virus is a common human pathogenic agent that has caused serious respiratory illness and death over the past century and in recent year. Treatment options against pandemic influenza strain A/H1N1 are very limited and unsatisfactory. Therefore we have developed iron oxide nanoparticles (IO-NPs) with particle size in the range of 10–15 nm against pandemic influenza strain A/H1N1/Eastern India/66/PR8-H1N1. Cell viability and anti-influenza activity was measured by MTT assay, plaque inhibition and quantifying viral transcripts using quantitative real-time PCR with Iron oxide nanoparticles in a dose- and time-dependent manner. 50% cell viability (TD 50) was observed at 4.25 pg ±.2 pg of Iron oxide nanoparticles. The percentage of plaque inhibition relative to the infection and the IC 50 (50% virus reduction) of PR8-H1N1strain (0.5 moi) were measured in vitro by the plate forming unit (pfu) in MA104 cells. Finding were observed at 01 pg after 72 h. The Antiviral activity determined by change in viral RNA transcripts within 24 h of virus infection by RT-PCR, 08 fold reductions in virus found when treated with Iron oxide nanoparticles Thus; it opens a new avenue for use of IP-NPs against virus infections. [ABSTRACT FROM AUTHOR]

Abstract It is reported the magnetic coating structure has a significant influence on their microwave absorption performance (MAP) for nano-Fe 3 O 4 -coated CNT. However, it is still uncertain which type of coating structure is favorable for Fe 3 O 4 -coated reduced graphene oxides (rGO) to enhance the MAP. In this work, nano-Fe 3 O 4 compact-coated rGO (FCG) and Fe 3 O 4 loose-coated rGO (FLG) are prepared firstly and their MAP have been investigated. A strong coating structure dependent effect is found and the FCG is proved to own much better MAP than FLG. Afterwards, the nano-Fe 3 O 4 compact-coated CNT and rGO mixture (FCCG) are fabricated. It is shown that the MAP could reach as low as −42.9 dB, and the high coverage density of Fe 3 O 4 nanoparticles plays important role on achieving this excellent property. Furthermore, in order to investigate the synergistic effects between CNT and rGO, FCCG with different mass ratios of CNT to rGO have been synthesized and optimized to maximize the effective complementarities between the dielectric loss and the magnetic loss to obtain high MAP. Results show the FCCG with 50 wt% rGO content achieves the best MAP, which can be attributed to the promoted consequent dielectric relaxation process and the magnetic loss induced by the increased multiple interface. Graphical abstract Composite with excellent MAP has been obtained guided by the proposed coating structure-property relationship for nano Fe 3 O 4 coated carbon-based materials. Image 1 [ABSTRACT FROM AUTHOR]

The importance of atherosclerosis is driving research to create improved diagnostic tools based on molecular imaging. Pretargeted imaging is the use of bioorthogonal probes that selectively accumulate upon reaction with a pre-modified biomolecule in vivo. To date, this very promising approach has not been applied to atherosclerosis. Neither has been the use of a single nano-radiomaterial for PET / T 1 -MR imaging of atherosclerosis. Here, we synthesized bioorthogonal nano-radiomaterials for in vivo pretargeted molecular imaging in a mouse model of atherosclerosis. Based on tetrazine-ligation, these functionalized 68Ga iron oxide nano-radiomaterials provide simultaneous PET and T 1 -MRI signals and selectively accumulate in atherosclerotic plaques in mice sequentially injected with trans-cyclooctene-modified antibodies against oxidized LDL followed by the hybrid nano-radiomaterial. Our results demonstrate the ability of this approach to unambiguously detect atherosclerosis. Furthermore, we show the first example of how hybrid imaging can be used for pretargeted bioorthogonal molecular imaging with nanomaterials. Unambiguous detection of atherosclerosis by the in vivo reaction of 68Ga iron oxide nanoparticles with anti-oxidized phospholipids antibody. Unlabelled Image [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Despite the advances in molecularly targeted therapies, delivery across the blood-brain barrier (BBB) and the targeting of brain tumors remains a challenge. Like brain, bone is a common site of metastasis and requires therapies capable of discerning the tumor from its healthy cellular milieu. To tackle these challenges, we made a variation on the previously proposed concept of the earthicle and fabricated an aqueous, surfactant-free ferrofluid containing superparamagnetic iron oxide nanoparticles (SPIONs) coated with silicate mesolayers and carbon shells, having 13 nm in size on average. Nanoparticles were synthesized hydrothermally and characterized using a range of spectroscopic, diffractometric, hydrodynamic and electron microscopy techniques. The double coating on SPIONs affected a number of physicochemical and biological properties, including colloidal stability and cancer targeting efficacy. Nanoparticles decreased the viability of glioblastoma and osteosarcoma cells and tumors more than that of their primary and non-transformed analogues. They showed a greater preference for cancer cells because of a higher rate of uptake by these cells and a pronounced adherence to cancer cell membrane. Even in an ultralow alternate magnetic field, nanoparticles generated sufficient heat to cause tumor death. Nanoparticles in MDCK-MDR1 BBB model caused mislocalization of claudin-1 at the tight junctions, underexpression of ZO-1 and no effect on occludin-1 and transepithelial resistance. Nanoparticles were detected in the basolateral compartments and examination of LAMP1 demonstrated that nanoparticles escaped the lysosome, traversed the BBB transcellularly and localized to the optic lobes of the third instar larval brains of Drosophila melanogaster. The passage was noninvasive and caused no adverse systemic effects to the animals. In conclusion, these nanoparticulate ferrofluids preferentially bind to cancer cells and, hence, exhibit a greater toxicity in these cells compared to the primary cells. They are also effective against solid tumors in vitro , can cross the BBB in Drosophila, and are nontoxic based on the developmental studies of flies raised in ferrofluid-infused media. Statement of Significance We demonstrate that a novel, hydrothermally synthesized composite nanoparticle-based ferrofluid is effective in reducing the viability of osteosarcoma and glioblastoma cells in vitro , while having minimal effects on primary cell lines. In 3D tumor spheroids, nanoparticles greatly reduced the metastatic migration of cancer cells, while the tumor viability was reduced compared to the control group by applying magnetic hyperthermia to nanoparticle-treated spheroids. Both in vitro and in vivo models of the blood-brain barrier evidence the ability of nanoparticles to cross the barrier and localize to the brain tissue. These composite nanoparticles show great promise as an anticancer biomaterial for the treatment of different types of cancer and may serve as an alternative or addendum to traditional chemotherapies. [ABSTRACT FROM AUTHOR]

Highlights • Impact of differently modified dextran coated nanoparticles on HEWL fibrillization. • Nanoparticles inhibit formation of HEWL fibrils in concentration-dependent manner. • Size of nanoparticles influenced the extent of their inhibitory properties. • The highest inhibitory effect was observed for the smallest CMdex NPs. • Dextran coated nanoparticles are not toxic at concentration close to IC 50 values. Abstract More than 50 diseases are associated with a conversion of proteins or peptides from their soluble functional states to highly organized fibrillar aggregates called amyloid fibrils. Due to the specific physico-chemical properties, specifically designed iron oxide nanoparticles may be an effective strategy for inhibiting the amyloid fibrillization of proteins. The inhibitory effect of three types of iron oxide nanoparticles coated with differently modified dextran on lysozyme fibrils formation was studied by Thioflavin T assay and atomic force microscopy. The size and zeta potential of studied nanoparticles were determined by dynamic light scattering. It had been found that nanoparticles are able to inhibit formation of lysozyme amyloid aggregates in concentration-dependent manner. Our results suggest that size of nanoparticles influenced the extent of their inhibitory properties. Moreover, the most effective nanoparticles were not toxic after 48 h incubation with neuroblastoma SH-SY5Y cell line at concentration close to IC 50 values. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fe 2 O 3 nanoparticles were embedded into hypercrosslinked porous polymeric matrix. • An increase in the content of Fe 2 O 3 nanoparticles reduced the specific surface area. • 7%Fe 2 O 3 -Porolas prepared using iron oxalate showed high adsorption capacity. • Almost complete decolorization of MB (96–98%) and >97% TOC were achieved. • Inexpensive and efficient Fe 2 O 3 -Porolas composite can be used in water treatment. Abstract The use of polymer sorbents in wastewater treatment can generate large-scale secondary waste due to the oxidation of the polymer matrix, stemming from the ionogenic functional groups or impurities. In this work, amorphous Fe 2 O 3 nanoparticles were embedded into a porous non-ionogenic polymer matrix (Porolas) using two different Fe(III) salts (iron nitrate and iron oxalate) for designing an easily separable and recyclable photocatalytic system. The Fe 2 O 3 -Porolas composites were prepared by a simple method: an impregnation of the Porolas by Fe(III) salts and calcination at 250 °C for 1 h. The sorption capacity and photocatalytic activity of the Fe 2 O 3 -Porolas composites were evaluated by the removal of methylene blue (MB) from model-contaminated water under UV light irradiation in the presence of oxalic acid. The characterization results, particularly from X-ray photoelectron spectroscopy and Mössbauer spectroscopy, confirmed the formation of highly dispersed amorphous Fe 2 O 3 nanoparticles that are embedded in the Porolas matrix. An increase in the content of the embedded Fe 2 O 3 nanoparticles decreased specific surface area (S BET), MB sorption capacity, and apparent photodegradation rate constant (k app) but increased the photodegradation efficiency of MB. The enhancement in MB removal can be attributed to the photocatalytic activities of the Porolas and Fe 2 O 3 nanoparticles (heterogeneous photocatalysis), sorption effect, and leaching of Fe ions in aqueous solution (homogeneous photocatalysis). The scaffold network of the Porolas and highly dispersed Fe 2 O 3 nanoparticles additionally contributed to the enhancement of photocatalytic activity of the Fe 2 O 3 -Porolas composite. Almost complete decolorization of MB (96–98%) and more than 97% TOC were achieved in this study, confirming simultaneous mineralization of both MB and OA in aqueous solution. The Fe 2 O 3 -Porolas composite can be easily prepared and inexpensive to design an easily separable and recyclable photocatalytic system for wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract We report monodisperse, chain-like particles (nanochains) consisted of silica-coated maghemite (γ-Fe 2 O 3) nanoparticle clusters prepared by colloidal chemistry and magnetic field-induced self-assembly of nanoparticle clusters. In order to quantify the shapes of chain-like particles, we have used the measure for shape convexity which is also called solidity. We functionalize the surface of the nanochains with amino (NH 2) and carboxyl groups (COOH) in order to modify surface charge. These surfaces of nanochains provide better colloidal stability and their potential for practical applications in biomedicine. The enhanced colloidal stability of the surface modified nanochains is confirmed by Zeta potential (ζ-potential) analysis. Magnetic properties of the nanochains show superparamagnetic state at room temperature since the nanochains are composed of tiny nanoparticles as their building blocks. The measured M (H) data at room temperature have been successfully fitted by the Langevin function and magnetic moment μ p = 20,526 μ B for sphere-like nanoparticle clusters and μ p = 20,767 μ B for nanochains are determined. The determined magnetic parameters have revealed that the nanochains show a magnetic moment of the nanoparticles higher than the one of individual nanoparticle clusters. These differences can be attributed to the collective magnetic properties of superparamagnetic iron oxide nanoparticles (SPION) assembled in different morphologies (isotropic and anisotropic morphology). Graphical Abstract Unlabelled Image Highlights • Uniform maghemite nanochains are synthesized by colloidal chemistry. • Shape of the nanochains is quantified by easily computable solidity measure. • Magnetic measurements of the nanochains show superparamagnetic properties. • Magnetic properties point to the shape anisotropy of the nanochains. [ABSTRACT FROM AUTHOR]

Abstract The iron-oxide nanoparticles (IONPs) filled multi-walled carbon nanotubes (IONP-MWCNTs hybrid) were directly synthesized via chemical vapour deposition method with acetylene as a carbon source. The bare IONPs were synthesized by hydrothermal method and the prepared bare IONPs were employed as a catalytic-support as well as a filling agent for the synthesis of IONP-MWCNTs hybrid at about 800 °C under atmospheric pressure. The synthesized IONP-MWCNTs hybrid was characterized by various physicochemical techniques including X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy and high-resolution transmission electron microscopy. The results demonstrate that the carbon nanotubes were successfully generated on the IONPs with the high yield because of unique carbon-iron metal interactions. An average diameter of synthesized IONPs and MWCNTs are around 9 and 50 nm, respectively. In addition, the HRTEM images and Raman spectrum confirms the obtained IONP-MWCNTs hybrid is well graphitic without major carbonaceous impurities. The electrochemical activity of the synthesized IONP-MWCNTs hybrid was performed in 2 M KOH using a three-electrode cell setup with a saturated Ag/AgCl as a reference electrode and a platinum plate as a counter-electrode by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy techniques. This electrode active material (IONP-MWCNTs hybrid) possess excellent supercapacitive behaviour and has excellent cyclic stability, even after 5000 cycles of charge-discharge at 4 A g−1 as current density. Thus, the synthesized IONP-MWCNTs hybrid will be a suitable as well as an economical electrode active material for high-performance supercapacitors. Graphical abstract Image 1 Highlights • IONPs was successfully filled inside of the MWCNTs by a simple CVD method. • Fabricated IONP MWCNTs delivered a high C s about 231 F g−1 at 4 A g−1. • This electrode material has excellent cyclic stability even after 5000 cycles. • Moreover, this method offers an economical way to get high-performance capacitors. [ABSTRACT FROM AUTHOR]

Abstract Magnetic nanoparticles (MNP) have been developed in the recent years for various applications like cell separation, immunoassay, and drug delivery. The present study involves the synthesis of stable, biocompatible Iron oxide MNP by coprecipitation of ferric chloride and ferrous chloride with Polyethylene glycol (PEG) as a surfactant to coat the nanoparticles twice. Scanning electron microscopic (SEM) images confirm the formation of uniform MNPs of size 12–17 nm. The peak at 582.2 cm−1 in the Fourier transform infrared spectrum (FTIR) corresponds to the Fe–O bond and the peak at 1104.1 cm−1 corresponds to a characteristic peak of PEG binding to the iron core. Tumor tissues selectively targeted with MNPs when placed in a magnetic field increases the temperature of the tumor tissues. The phantom study shows that there is a minimum of 1.3 °C and a maximum of 6.7 °C rise in temperature with increasing concentration of the nanoparticles embedded in the phantoms; this proved the possibility of enhancement of thermal images using MNPs and its usage for thermal ablation of cancer. MNPs can also be used as a contrast agent for magnetic resonance imaging (MRI). [ABSTRACT FROM AUTHOR]

Tunable, one-dimensional (1D) nanofiller assembly using oscillating magnetic fields in the low frequency range (<5 Hz) is studied as a scalable and energy-efficient method to structure nanofillers within viscous matrices to deliver anisotropic, multi-functional polymer nanocomposites (PNCs). In this work 1D assembly tailoring was first experimentally studied and demonstrated using the model system of superparamagnetic iron oxide nanoparticles (SPIONs, 15 nm, 0.02–0.08 vol%) in DI water using varying magnetic fields (0–5 Hz frequency, 10–100 G magnetic flux density, and square and sinusoidal waveforms). In addition to lateral assembly of nanofillers, when the field oscillation is turned on, transverse assembly can be introduced as the magnetic moments of the particles respond to the changing fields by Brownian rotation. The degree of transverse assembly, in balance with lateral assembly and the resulting nanofiller patterns, was observed to be determined by the magnetic field parameters, magnetic responsiveness of the nanofillers, and the matrix viscosity. Based on this assembly study, PNCs consisting of ferrimagnetic iron oxide nanofillers in a thermoset polymer, with two different linear nanoparticle patterning, were successfully fabricated using small magnetic fields (<100 G) even in a viscous matrix (70 cP) with a short assembly time of 30 min. This work can contribute to scalable manufacturing and thus bulk application of multi-functional PNCs enabled by more precise nanofiller and interface structuring. [ABSTRACT FROM AUTHOR]

The pure and tin-doped iron oxide nanoparticles were synthesized by using the microwave irradiation method by varying the different wt% of Sn. Samples with better quality were prepared using 0.1 mol of Hexadecyl trimethyl ammonium bromide (HTAB) as surfactant. The influence of Sn levels lead to change in morphology of rhombus shaped platelets at lower doping levels of Sn into spherical shaped particles at higher doping levels. The respective change due to the Sn wt% in iron oxide was also altered the particle size, which was verified with the help of XRD and HR-TEM studies. The diffusion of Sn in an iron oxide lattice by incorporating Fe 3+ sites were confirmed with the help of XPS spectrum. The electrical conductivity change was observed due to Sn doping levels in iron oxide. The tuning of bandgap variations on electrical conductivity was confirmed due to decrease of conductivity of higher doping level of Sn in iron oxide nanoparticles. The bandgap of iron oxide nanoparticle was tuned from 2.21 eV to 2.44 eV due to the incorporation of Sn in an iron oxide lattice. The change in band gap energy due to this reason is highly influenced on degradation of methylene blue dye. Photocatalytic activity under sunlight is clearly identified by the degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The nanoparticles synthesized using Terminalia catappa leaf extract gave a mixture of Fe 2 O 3 and Fe 3 O 4 nanoparticles. • Cytotoxic behavior of the synthesized nanoparticles showed attack on both the normal (HEK 293) and cervical carcinoma (Hela) cell lines. • The effectiveness of nanoparticles towards anticancer properties depends of reaction conditions. In this research, iron oxide nanoparticles were synthesized by plant-mediated method. Their optical nature, crystallinity, composition, microscopy and sizes were characterized using energy dispersive X-ray, X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy. The microscopic studies revealed spherical/polygonal morphologies with average particle size of 19.14 nm. The in-vitro cytotoxic analysis of the nanoparticles against HEK 293 normal cell lines and Human cervical (Hela) cell lines showed cell toxicity with IC 50 values 44.12 μg and 34.94 μg respectively. The antimicrobial tests showed sensitivity to some micro-organisms whereas some were resistant. In general, the nanoparticles displayed broad spectrum activity with Methicillin Resist Staphaureus (MRSA) showing the greatest growth inhibition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel catalytic system consisted of iron oxide magnetic nanoparticle and catechol. • Catechol-generated ROS further converted to hydroxyl radical by iron. • Initiates polymerization of wide ranges of monomers in an oxygenated solution. • Magnetic, bilayer hydrogels were formed with improved mechanical property. Phenol and its derivatives are the most used polymerization inhibitors for vinyl-based monomers. Here, we reported a novel catalytic system composed of mussel inspired adhesive moiety, catechol, in combination with iron oxide nanoparticles (IONPs) to generate hydroxyl radical (OH) at pH 7.4. Catechol-containing microgel (DHM) was prepared by copolymerizing dopamine methacrylamide (DMA) and N -hydroxyethyl acrylamide (HEAA), which generated superoxide (O 2 −) and hydrogen peroxide (H 2 O 2) as a result of catechol oxidation. In the presence of IONPs, the generated reactive oxygen species were further converted to OH, which initiated free radical polymerization of various water-soluble acrylate-based monomers including neutral (acrylamide, methyl acrylamide, etc.), anionic (2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt), cationic ([2-(methacryloyloxy)ethyl]trimethylammonium chloride), and zwitterionic (2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide) monomers. Compared with the typical free radical initiating systems, the reported system does not require the addition of extra initiators for polymerization. During the process of polymerization, a bilayer hydrogel was formed in situ and exhibited the ability to bend during the process of swelling. The incorporation of IONPs significantly enhanced magnetic property of the hydrogel and the combination of DHM and IONPs also improved the mechanical properties of these hydrogels. [ABSTRACT FROM AUTHOR]

Understanding water absorbency in paper is challenging as fibre swelling and out-of-plane deformation occur simultaneously during liquid imbibition. Liquid absorption is commonly accessed by gravimetric tests, which provides limited information on the local spatial and temporal distribution of fluid in the substrate. In this work, we developed iron tracers to map liquid imbibition in paper by in situ precipitation of iron oxide nanoparticles during passage of the wetting front. The iron oxide tracers were found to be robustly attached to the cellulosic fibres. After liquid absorption tests, absorbency was investigated by mapping the distribution of iron in 3D using X-ray micro-computed tomography (μCT) and in 2D using energy-dispersive X-ray spectroscopy. We demonstrate a difference in tracer distribution between the wetting front and the fully saturated region supporting that imbibition proceeds in two phases, i.e. liquid percolation through the cell wall initially prior to filling of the external pore spaces. Critically, we demonstrate that these iron tracers enhance image contrast and allow for new imaging modalities in μCT for fibre networks. [Display omitted] [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles (MNPs) have gained significant attention among several nanoscale materials during the last decade due to their unique properties. These properties make them successful nanofillers for drug delivery and a number of new biomedical applications. MNPs are more useful when combined with biodegradable polymers. In this review, we discussed the synthesis of polycaprolactones (PCL) and the various methods of synthesizing magnetic iron oxide nanoparticles. Then, the synthesis of composites that is made of PCL and magnetic materials (with special focus on iron oxide nanoparticles) were highlighted. In addition, we comprehensively reviewed their application in drug delivery, cancer treatment, wound healing, hyperthermia, and bone tissue engineering. Other biomedical applications of the magnetic PCL such as mitochondria targeting are highlighted. Moreover, biomedical applications of magnetic nanoparticles incorporated into other synthetic polymers apart from PCL are also discussed. Thus, great progress and better outcome with functionalized MNPs enhanced with polycaprolactone has been recorded with the biomedical applications of drug delivery and recovery of bone tissues. [Display omitted] • Methods of synthesizing polycaprolactones (PCL) polymer were discussed. • Composites made from PCL and magnetic nanoparticles were examined. • Biomedical applications of the magnetic composites were comprehensively reviewed. • Performance of other non-PCL polymeric composites were highlighted. [ABSTRACT FROM AUTHOR]

A co-precipitation synthesis method was used to obtain iron oxide nanoparticles coated with Yerba Mate ( Ilex paraguariensis ) extract. These particles have a core–shell structure with the iron oxide phase surrounded by an organic shell provided by an organic component which come from the Yerba Mate extract. Obtained nanoparticles were exhaustively characterized as powders and in aqueous colloidal suspensions using several techniques such as TEM, XRD, SAXS, TGA, ATR-FTIR, Raman and XPS spectroscopy, magnetic moment measurement and specimen ac susceptibility. All results together show that the obtained particles are single-crystal iron oxide particles with magnetite as the most probable phase. Yerba Mate extract shell mass to iron oxide core mass, m S /m c , could be increased up to 6.2 × 10 −2 , depending on the synthesis conditions. As a function of m S /m c the crystallite size of the nanoparticles decreased from about 15 nm to 11 nm, while saturation magnetization Ms and coercive field Hc of powders decreased . Ms. diminution was associated to increasing modification of core surface electronic states due to chemical bond of iron in iron oxide to Yerba Mate extract components; on the other hand, coercivity reduction was modelled on the basis of the increasing interparticle separation and dipolar interaction weakening, which occurs as shell thickness grows. Differences between the particle core mean size obtained with TEM, SAXS, XRD and magnetic measurements are observed. The fact that magnetic size was smaller than particle and crystallite sizes was attributed to the existence of intense dipolar interactions. It was found that low field susceptibility in a colloid sample was about 2.5 times that of the powder specimen, a result that shows that demagnetizing effects prevail in the powder specimen, while they may be absent in the colloid due to the larger interparticle mean separation expected in the latter. Analysis of powder and colloid susceptibility was done based on a recently developed model was in agreement with the one performed for the coercive field behaviour. [ABSTRACT FROM AUTHOR]

The fiber-shaped supercapacitor is a promising energy storage device in wearable and portable electronics because of its high flexibility, small size, and light weight. However, most of the reported fiber-shaped supercapacitors have exhibited low capacitance and energy density due to the limited surface area between the two fiber electrodes and operating voltage range. Herein, we successfully developed a coaxial fiber-shaped asymmetric supercapacitor (CFASC) made from MnO 2 /CNT-web paper as a cathode coupled with Fe 2 O 3 /carbon fiber as an anode with a high operating voltage of 2.2 V. The prepared CFASC device showed a high volumetric energy density of 0.43 mWh cm −3 at a power density of 0.02 W cm −3 , which is comparable to those of previously reported fiber-shaped supercapacitors. Additionally, CFASC exhibited good rate capability, long cycle life, and high volumetric capacitance (0.67 F cm −3 ) with excellent flexibility. The promising performance of CFASC illustrated its potential for portable and wearable energy storage devices. [ABSTRACT FROM AUTHOR]

CNT/GNF/Fe 2 O 3 ternary composites were synthesized via a simple hydrothermal route. The electrochemical findings reveal that the incorporation of iron oxide (Fe 2 O 3 ) into CNT/GNF (174 F g −1 ) boosts the specific capacitance (C s ) to 307 F g −1 at 10 mV s −1 . The system also shows good capacity retention, as it maintained 92% of its original capacitance after 200 cyclic voltammetry cycles. Physicochemical characterization shows that Fe 2 O 3 was anchored randomly on the CNT/GNF sidewalls, forming a network for facile ion diffusion. The improved supercapacitance of CNT/GNF/Fe 2 O 3 can be ascribed to the synergistic effect of the double-layer capacitance of CNT/GNF and the pseudocapacitance of Fe 2 O 3 . [ABSTRACT FROM AUTHOR]

We report a nanoparticulate iron oxide based catalyst for CO 2 conversion with high efficiency at low pressures and on the effect of the presence of copper on the catalyst’s restructuring and its catalytic performance. In situ X-ray scattering reveals the restructuring of the catalyst at the nanometer scale. In situ X-ray absorption near edge structure (XANES) shows the evolution of the composition and oxidation state of the iron and copper components under reaction conditions along with the promotional effect of copper on the chemical transformation of the iron component. X-ray diffraction (XRD), XANES and Raman spectroscopy proved that the starting nanocatalyst is composed of iron oxides differing in chemical nature (α-Fe 2 O 3 , Fe 3 O 4 , FeO(OH)) and dimensionality, while the catalyst after CO 2 conversion was identified as a mixture of α-Fe, Fe 3 C, and traces of Fe 5 C 2 . The significant increase of the rate CO 2 is turned over in the presence of copper nanoparticles indicates that Cu nanoparticles activate hydrogen, which after spilling over to the neighbouring iron sites, facilitate a more efficient conversion of carbon dioxide. [ABSTRACT FROM AUTHOR]

Bionanocomposites fabricated using metal nanoparticles serve a wide range of biomedical applications viz., site targeted drug delivery, imaging etc. Theranostics emerge as an important field of science, which focuses on the use of single entity for both disease diagnosis and treatment. The present work aimed at designing a multifunctional nanocomposite comprising of iron/gold hybrid nanoparticles, coated with oleyl chitosan and conjugated with methotrexate. The HR-TEM images revealed the spherical nature of the composite, while it's nontoxic and biocompatible property was proved by the MTT assay in NIH 3T3 cells and hemolysis assay. Though the VSM results exhibited the magnetic property, the MRI phantom images and X-ray contrast images demonstrated the potential of the composite to be used as contrast agent. Thus the prepared nanocomposite possess good cytocompatibility, magnetic property and also high X-ray attenuation, wherein it could serve as a novel platform for both MRI and CT diagnosis, as well as drug conjugation could aid in targeted drug delivery. [ABSTRACT FROM AUTHOR]

Nitrogen-doped carbon-coated and graphene oxide-wrapped Fe 3 O 4 nanoparticles were prepared using the electrostatic force between polyethyleneimine-functionalized Fe 3 O 4 nanoparticles and graphene oxide layers, followed by annealing in an N 2 atmosphere (Fe 3 O 4 @NCG). The electrochemical performance of Fe 3 O 4 @NCG was superior to that of graphene oxide- or reduced graphene oxide-wrapped Fe 3 O 4 nanoparticles and carbon-coated Fe 3 O 4 nanoparticles. Fe 3 O 4 @NCG exhibited stable specific capacity of ∼895 mAh g −1 after 350 cycles over the voltage range 0.001–3.0 V vs. Li/Li + . The superior performance of Fe 3 O 4 @NCG was attributed to the presence of a nitrogen-doped carbon layer and networks of reduced graphene oxide. The chemical route-derived Fe 3 O 4 @NCG may be a promising anode material for high-performance lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The effects of polyvinylpyrrolidone (PVP) on the formation of iron oxide nanoparticles during polyol synthesis are described. The addition of PVP during synthesis changes the particle morphology from compact to porous with chains of small iron oxide nanocrystals at the surface of the particles due to the steric repulsion of PVP ligands. The addition of PVP also reduces average particle size from 857 nm to 225 nm by preventing agglomeration. In addition, the presence of PVP restricts crystal growth of iron oxide and limits oxidation. The high-surface areas achieved for the powders can be useful for catalytic applications. [ABSTRACT FROM AUTHOR]

Currently, considerable effort is being made towards synthesis and characterization of iron oxide nanoparticles. In this article, we report on the preparation and characterization of iron oxide nanoparticle (NP) arrays supported on natively oxidized Si(100) surface. The NPs are synthesized by reverse micelle nanolithography technique and are then deposited onto natively oxidized Si(100) surface via spin-coating. Plasma oxidation followed by high temperature annealing results in a unimodal size distribution of pseudohexagonally-ordered array of iron oxide NPs (with ∼14 nm mean diameter and ∼5 nm mean height). High temperature annealing does not fragment the NPs. Particles are sinter-resistant: the unimodal arrays are robust with respect to thermal treatment. X-ray absorption spectroscopy (XAS), including X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS), reveals that structure of the iron oxide particle resembles closely the hematite α-Fe 2 O 3 structure. Furthermore, with the help of EXAFS spectra, we eliminate the possibility of γ-Fe 2 O 3 , Fe 3 O 4 , FeO and FeO(OH) structures for the NPs. [ABSTRACT FROM AUTHOR]