Modified Fe3O4 Nanoparticles Research Articles

Tannic acid and trivalent iron modified Fe3O4 nanoparticles as a new adsorbent to remove uranium from wastewater

This study reports the preparation and application of Fe3O4 nanoparticles modified by tannic acid and trivalent iron for U(Ⅵ) removal. The phenolic hydroxyl group on the tannic acid molecule can be complexed with U(Ⅵ), so as to achieve the goal of adsorping uranium from wastewater, and the maximum adsorption capacity of TA-FeIII@Fe3O4 can reach 98.2 mg/g. Through the research on pH, dosage, adsorption kinetics and adsorption thermodynamics indicted that it were excepting as a new green adsorbent for removing U(Ⅵ) from wastewater.

Durable microstructure-based superhydrophobic composite with photothermal performance for multifunctional application

Nowadays, multifunctional superhydrophobic coating has drawn widespread attention by virtue of its great water-repellent property, whereas the fragile mechanical and chemical durability of superhydrophobic coating greatly limits its practical application. Herein, a robust and multifunctional superhydrophobic composite coating (CFRE-SP@Fe3O4) with anti-corrosion, delay-icing and self-deicing performance is constructed via simple imprinting-demolding process on the carbon fiber reinforced epoxy resin (CFRE) surface and post-deposition modification with polydimethylsiloxane (PDMS) and epoxy resin modified Fe3O4 nanoparticles. The obtained CFRE-SP@Fe3O4 coating displays a superhydrophobic property with a WCA of 155° ± 1.2°. By virtue of the protection effect of the robust micro-grid structures for the inner superhydrophobic Fe3O4 nanoparticles (SP@Fe3O4), the CFRE-SP@Fe3O4 coating still maintains great superhydrophobicity after linear friction for 100 times. Additionally, compared with the carbon steel treated with CFRE, the impedance modulus at lowest frequency of CFRE-SP@Fe3O4 coating treated group further increase with a value of 107 Ω·cm2, confirming the excellent anti-corrosion performance. Owing to the air pocket captured by the micro-/nanostructure on the superhydrophobic surface, the icing time of the CFRE-SP@Fe3O4 surfaces extends from 60 s to 2130 s. Moreover, combined with the photothermal conversion performance of carbon fiber and Fe3O4 nanoparticles, the ice on the CFRE and CFRE-SP@Fe3O4 coatings surfaces begin to melt 137 s, displaying the excellent self-deicing performance.

Fabrication of fluorinated superhydrophobic oil-absorption cabins with controllable movement, elasticity, and wear resistance

Superhydrophobic materials that can withstand harsh environments are critical in oil spills. Here, fluorinated superhydrophobic monoliths were prepared in one step based on a high internal phase emulsion (HIPE) templating method. γ-methacryloyloxypropyltrimethoxysilane (KH570)-modified Fe3O4 nanoparticles were added into the emulsion as co-stabilizers and participated in the composition of micro-nano hierarchical structures. The fluorinated alkyl backbone and rough structure enabled the foam to exhibit excellent superhydrophobicity with a water contact angle (WCA) of 153.5° and a sliding angle (SA) of 5.92°. The unique structure and composition of the foam allowed it to maintain stable superhydrophobicity (153.97°) even after severe sandpaper abrasion tests (Drawn 10 m at 7.1 kPa on P400 grit sandpaper). It also demonstrated exceptional hydrophobicity to strong acids, bases, and UV light. The oil-saturated material can be regenerated through a simple extrusion process, showing outstanding reusability. After ten cycles of oil adsorption, the adsorption capacity remains above 90 % of the initial value. The additional magnetic properties of the material enable it to remove oil in confined or hazardous conditions. More importantly, with the assistance of a vacuum pump, the material permits continuous separation of organic solvents from the water. These excellent properties of the foam make it a potential material for treating wastewater.

Foam drainage agent with enhanced foam stability through modified Fe3O4 nanoparticles

A nanofoam drainage agent was developed to address the challenges of inadequate foam stability and foaming efficiency in the gas recovery process of foam drainage. The formulation of the primary foam drainage agent was obtained by screening and combining conventional anionic and amphoteric surfactants. Experimental results revealed a synergistic interaction between α-olefin sulfonate (AOS) and lauramidopropyl betaine (LAB-35). Specifically, when a mixture of 0.4 wt.% AOS and 0.1 wt.% LAB-35 was used, the surface tension of the primary foam drainage agent was measured to be 23.32 mN/m. Furthermore, modification of Fe3O4 nanoparticles with the silane coupling agent γ-(methacryloxy)propyl trimethoxysilane (KH-570) was performed to improve the dispersibility in aqueous solutions and enhance foam stability. The results of infrared spectroscopy, x-ray diffraction, thermogravimetric analysis, and contact angle measurements revealed the effective bonding of KH-570 to the surface of Fe3O4 nanoparticles. Additionally, the particle size distribution in the aqueous solution showed the excellent dispersion of the modified Fe3O4 nanoparticles. Through the incorporation of the modified Fe3O4 nanoparticles into the primary foam drainage agent, a nanofoam drainage agent with a half-life of 989 ± 6.5 s was developed. Microscopic observations of foam coarsening behavior revealed the mechanism behind foam stability. Performance testing of the foam drainage agent demonstrated the agent’s outstanding resistance against salinity, temperature, and oil and its remarkable liquid-carrying capacity.

Magnetic Hyperporous Elastic Material with Excellent Fatigue Resistance and Oil Retention for Oil-Water Separation.

Oily wastewater has caused serious threats to the environment; thus, high-performance absorbing materials for effective oil-water separation technology have attracted increasing attention. Herein, we develop a magnetic, hydrophobic, and lipophilic hyperporous elastic material (HEM) templated by high internal phase emulsions (HIPE), in which free-radical polymerization of butyl acrylate (BA) and divinylbenzene (DVB) is employed in the presence of poly(dimethylsiloxane) (PDMS), lecithin surfactant, and modified Fe3O4 nanoparticles. The adoption of the emulsion template with nanoparticles as both stabilizers and cross-linkers endows the HEM with biomimetic hierarchical open-cell micropores and elastic cross-linked networks, generating an oil absorbent with outstanding mechanical stability. Compressive fatigue resistance of the HEM is demonstrated to endure 2000 mechanical cycles without plastic deformation or strength degradation. By exploiting the synergistic effect of hierarchical structures and low-surface-energy components, the resulting HEM also possesses excellent and robust hydrophobicity (water contact angle of 164°) and good oil absorption capacity, in which Fe3O4 nanoparticles lead to convenient magnetically controlled oil recyclability as well. Notably, the unique biomimetic microporous structure demonstrates superior oil retention capacity (>95% at 1000 rpm and >60% at 10,000 rpm) over the state-of-the-art porous materials for a diverse variety of oils to reduce the risk of secondary oil leakage, along with good recoverability by squeezing owing to the excellent compression resilience. These excellent performances of our HEM provide broad prospects for practical applications in oil-water separation, energy conversion, and smart soft robotics.

Supported of gold nanoparticles on carboxymethyl lignin modified magnetic nanoparticles as an efficient catalyst for reduction of nitroarenes and treatment of human melanoma

This article represents the synthesis and characterizations of Au NPs immobilized and carboxymethyl lignin (CML) modified Fe3O4 nanoparticles (Fe3O4@CML/Au NPs) following a bio-inspired protocol without the participation of any toxic and harmful reductant or stabilizers. Following various physicochemical methodologies, such as FT-IR, FE-SEM, TEM, EDX, XRD, VSM, and ICP-OES, the textural characteristics and different structural aspects were evaluated. The Fe3O4@CML/Au NPs nanocomposite was subsequently explored towards the catalytic reduction of diverse aromatic nitro functions using green conditions. An excellent yield were achieved within very short reaction time. Nine recycling runs of the nanocatalyst were completed without a discernible loss of catalytic activity, thanks to its easy magnetic recovery. The DPPH assay was carried out to examine the antioxidant effectiveness. The Fe3O4@CML/Au NPs nanocomposite inhibited half of the DPPH in a 250 μg/mL solution. To measure the anti-human melanoma efficacy of Fe3O4@CML/Au NPs nanocomposite, MTT assay was applied on HT144, MUM2C, IPC-298 and SKMEL24 cell lines. Fe3O4@CML/Au NPs nanocomposite had high anti-human melanoma efficacy on above tumor cells. The best finding of anti-human melanoma properties of Fe3O4@CML/Au NPs nanocomposite was seen in the case of the SKMEL24 cell line. The IC50 of Fe3O4@CML/Au NPs nanocomposite was 137, 145, 185, and 125 μg/mL against HT144, MUM2C, IPC-298 and SKMEL24 cells, respectively. This research exhibited remarkable anti-human melanoma and antioxidant efficacies of Fe3O4@CML/Au NPs nanocomposite in the in vitro condition.

Preparation of stable colloidal dispersion of surface modified Fe3O4 nanoparticles for magnetic heating applications

The effect of surface modification on enhancing the magnetic heating behavior of magnetic nano fluids were investigated, for this purpose Fe3O4 nanoparticles were synthesized using co-precipitation method and surface modification was done using citric acid, ascorbic acid, tetraethyl orthosilicate (TEOS), polyvinyl alcohol (PVA) and polyethylene glycol (PEG). Experimental heating tests using AC magnetic field were done in the frequency of 100 kHz and different magnetic field (H) intensities. Theoretically the specific absorption rate (SAR) in magnetic nano fluids is independent of nanoparticles concentration but the experimental results showed different behavior. The theoretical SAR value @ H = 12kA.m–1 for Nano fluids containing bare Fe3O4 nanoparticles was 11.5 W/g but in experimental tests the obtained value was 9.72 W/g for nano fluid containing 20,000 ppm of dispersed nanoparticles. The experimental SAR calculation was repeated for sample containing 10,000 ppm of nanoparticles and the results showed increase in experimental SAR that is an evidence of nanoparticles agglomeration in higher concentrations. The surface modification has improved the dispersion ability of the nanoparticles. The Ratio of SAR, experimental, 20000ppm to SAR, experimental, 10000ppm was 0.85 for bare Fe3O4 nanoparticles dispersion but in case of surface modified nanoparticles this ratio has increased up to 0.98 that shows lower agglomeration of nanoparticles as a result of surface modification, although on the other hand the surface modification agents were magnetically passive and so it is expected that in constant concentration the SAR for bare Fe3O4 nanoparticles to be higher than this variable for surface modified nanoparticles. At lower concentrations the dispersions containing bare Fe3O4 nanoparticles showed higher SAR values but at higher concentrations the surface modified Fe3O4 nanoparticles showed better results although the active agent amount was lower at them. Finally, it should be noted that the nanoparticles that were surface modified using polymeric agents showed the highest decrease in experimental SAR amounts comparing theoretical results that was because of the large molecules of polymers comparing other implemented surface modification agents.

Enhancing Enzyme Stability and Functionality: Covalent Immobilization of Trypsin on Magnetic Gum Arabic Modified Fe3O4 Nanoparticles.

This study aimed to fabricate gum Arabic (GA)-coated Fe3O4 nanoparticles bearing numerous active aldehyde groups on their surface, followed by an assessment of their capability as a magnetic support for the covalent immobilization of the trypsin enzyme for the first time. FT-IR, XRD, TGA, and SEM results demonstrated the successful synthesis of GA-coated Fe3O4 nanoparticles, along with the covalent immobilization of the enzyme onto the support. Immobilization enhanced the relative enzymatic activity across a range of aqueous solution pH levels (ranging from 4 to 11) and temperatures (ranging from 20 to 80 °C) without altering the optimum pH and temperature for trypsin activity. Kinetic studies using Michaelis-Menten plots revealed changes in kinetic parameters, including a lower Vmax and higher Km for immobilized trypsin compared to the free enzyme. The immobilization onto magnetic gum Arabic nanoparticles resulted in an improved stability of trypsin in the presence of various solvents, maintaining a stability order comparable to that of the free enzyme due to the stabilizing effect of the support. The reusability results showed that the immobilized enzyme can retain over 93% of its activity for up to 15 cycles.

Magnetically recyclable polydopamine-polyquaternium modified Fe3O4 nanoparticles for demulsification of asphaltene-rich ASP flooding produced water

The asphaltene-rich alkaline-surfactant-polymer (ASP) flooding produced water has been identified with high interfacial stability and severe secondary emulsification, which poses great difficulties in its demulsification process. This leads to an urgent need to develop targeted and efficient demulsifiers. In this research, a novel polydopamine-polyquaternium modified Fe3O4 (PQA-PDA@Fe3O4) nanoparticle integrates the electrical neutralization, interfacial adsorption and magnetic aggregation functionalities was prepared to dispose this emulsion. Primarily, structural and surface properties of the PQA-PDA@Fe3O4 demulsifier were systemically characterized by a series of analytical techniques, which presents its core-shell, hydrophilic and positively charged characters. When employing PQA-PDA@Fe3O4 to treat the produced water that contained 500 mg/L emulsified oil, a demulsification efficiency of 90.5 % was achieved at 200 mg/L dosage. It was found that the PQA-PDA@Fe3O4 nanoparticles could coalesce the fine oil droplets into large and dense aggregates, as demonstrated by the raised fractal dimension values. By monitoring the interfacial properties (interfacial tension, zeta potential and interfacial film elastic modulus) variations, the demulsification mechanism was further explored. The PQA-PDA@Fe3O4 nanoparticle could spontaneously migrate to the oil/water interface and reassemble a loose interfacial film, thus leading the oil droplets destabilization and aggregation. Notably, the magnetic force between the PQA-PDA@Fe3O4 nanoparticles significantly accelerates the oil droplets aggregation and inhibits the secondary emulsification process, so as to achieve the outstanding demulsification efficiency. Moreover, this PQA-PDA@Fe3O4 nanoparticle exhibited acceptable magnetic recyclability. These results provided an effective and alternative protocol to demulsify the asphaltene-rich ASP flooding emulsions.

Chitosan-gelatin/cetyltrimethylammonium bromide magnetic polymer composites as reusable high performance adsorbent for AR 18 removal

Magnetic chitosan (CS) cross-linked gelatin (Gel) polymer composites (MCGC) were fabricated by reacting CS with Gel in the present of carboxyl modified Fe3O4 nanoparticles and cetyltrimethylammonium bromide using glutaraldehyde as a crosslinking agent. MCGC possessed high zeta potential, abundant active functional groups including amino and hydroxyl groups and facile magnetic separation properties. The prepared MCGC exhibited excellent adsorption performance for AR 18 and the adsorption capacity reached as high as 344.63 mg/g. The adsorption kinetics was fitted well with the pseudo-second order model, while the adsorption isotherms followed the Redlich-Peterson equation best. The thermodynamic studies indicated the adsorption process was exothermic and spontaneous. The adsorption mechanism was studied including electrostatic interaction, hydrogen-bond interaction and π-π stacking between dyes and MCGC. Desorption and renewable experiments proved MCGC possessed high regeneration properties and reusability as an adsorbent.

A magnetic “Band-Aid” incorporated with Fe3O4 NPs modified epoxy binder for in-situ repair of organic coating under seawater

To repair the anti-corrosive coatings directly under seawater is an up-and-coming approach, which can effectively prolong the service life of coated steel structures once the coatings suffered from unexpected scratches. Inspired by the design of Band-Aid for the healing of wound, a magnetic “Band-Aid” (MB) combined with oleic acid modified Fe3O4 nanoparticles (OMNPs) was designed to realize the in-situ repair of anti-corrosion coatings under seawater and the experimental results indicated that this coating repair method by MB incorporated with OMNPs modified epoxy binder is satisfying and effective when the addition of OMNPs epoxy binder was more than 1.0 wt%. Furthermore, the penetration of seawater in the vertical direction of the coating can be prevented by MB during the curing process of epoxy binder, the formation of permeation channels parallel to the coating can be blocked with the aid of OMNPs, which mainly based on the magnetic force between the MB and substrate steel, as well as the competitive-wetting and target-driving functions of OMNPs. The current work may provide a feasible approach to repair the organic anti-corrosion coating directly, which coated on the steel structures under seawater.

Preparation of Hydrophobic Octadecylphosphonic Acid-Coated Magnetite Nanoparticles for the Demulsification of n-Hexane-in-Water Nanoemulsions.

To design more environmentally friendly, economical, and efficient demulsifiers for oily wastewater treatment, hydrophobic octadecylphosphonic acid (ODPA)-modified Fe3O4 nanoparticles (referred to as Fe3O4@ODPA) were prepared by condensation of hydroxyl groups between ODPA and Fe3O4 nanoparticles using the co-precipitation method. The prepared magnetite nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric/differential thermogravimetric (TG/DTG) analysis. The water contact angles (θW) of Fe3O4@ODPA nanoparticles were more than 120°, indicating hydrophobic nature, and the diameter of the obtained spherical-shaped magnetite nanoparticles was 12-15 nm. The ODPA coating amount (AO) (coating weight per gram Fe3O4) and specific surface area (SO) of Fe3O4@ODPA were 0.124-0.144 g·g-1 and 78.65-91.01 m2·g-1, respectively. To evaluate the demulsification ability, stability, and reusability, the magnetite nanoparticles were used to demulsify an n-hexane-in-water nanoemulsion. The effects of the magnetite nanoparticle dosage (CS), pH value of nanoemulsion, and NaCl or CaCl2 electrolytes on the demulsification efficiency (RO) were investigated. The RO of Fe3O4@ODPA samples was found to be higher than that of bare Fe3O4 samples (S0, ST, and SN) under all CS values. With the increase in CS, the RO of Fe3O4@ODPA samples initially increased and then approached equilibrium value at Cs = 80.0 g·L-1. A maximum RO of ~93% was achieved at CS = 100.0 g·L-1 for the Fe3O4@ODPA sample S2. The pH and two electrolytes had a minor effect on RO. The Fe3O4@ODPA nanoparticles maintained high RO even after being reused for demulsification 11 times. This indicates that the hydrophobic Fe3O4@ODPA samples can be used as an effective magnetite demulsifer for oil-in-water nanoemulsions.

Efficient magnetic capture of PE microplastic from water by PEG modified Fe3O4 nanoparticles: Performance, kinetics, isotherms and influence factors

Due to their resistance to degradation, wide distribution, easy diffusion and potential uptake by organisms, microplastics (MPs) pollution has become a major environmental concern. In this study, PEG-modified Fe3O4 magnetic nanoparticles demonstrated superior adsorption efficiency against polyethylene (PE) microspheres compared to other adsorbents (bare Fe3O4, PEI/Fe3O4 and CA/Fe3O4). The maximum adsorption capacity of PE was found to be 2203 mg/g by adsorption isotherm analysis. PEG/Fe3O4 maintained a high adsorption capacity even at low temperature (5°C, 2163 mg/g), while neutral pH was favorable for MP adsorption. The presence of anions (Cl−, SO42−, HCO3−, NO3−) and of humic acids inhibited the adsorption of MPs. It is proposed that the adsorption process was mainly driven by intermolecular hydrogen bonding. Overall, the study demonstrated that PEG/Fe3O4 can potentially be used as an efficient control against MPs, thus improving the quality of the aquatic environment and of our water resources.

Facile and selective separation of anthraquinones by alizarin-modified iron oxide magnetic nanoparticles

Anthraquinones are widely distributed in higher plants and possess broad biological activities. The conventional separation procedures for isolating anthraquinones from the plant crude extracts require multiple extraction, concentration, and column chromatography steps. In this study, we synthesized three alizarin (AZ)-modified Fe3O4 nanoparticles (Fe3O4@AZ, Fe3O4@SiO2-AZ, and Fe3O4@SiO2-PEI-AZ) by thermal solubilization method. Fe3O4@SiO2-PEI-AZ showed strong magnetic responsiveness, high methanol/water dispersion, good recyclability, and high loading capacity for anthraquinones. To evaluate the feasibility of using Fe3O4@SiO2-PEI-AZ for separating various aromatic compounds, we employed molecular dynamics simulations to predict the adsorption/desorption effects of PEI-AZ for various aromatic compounds in different methanol concentrations. The results showed that the anthraquinones could be efficiently separated from the monocyclic and bicyclic aromatic compounds by adjusting the methanol/water ratio. The Fe3O4@SiO2-PEI-AZ nanoparticles were then used to separate the anthraquinones from the rhubarb extract. At 5% methanol, all the anthraquinones were adsorbed by the nanoparticles, thus allowing their separation from other components in the crude extract. Compared with the conventional separation methods, this adsorption method has the advantages of high adsorption specificity, simple operation, and solvent saving. This method sheds light on the future application of functionalized Fe3O4 magnetic nanoparticles to selectively separate desired components from complex plant and microbial crude extracts.

Biomimetic ultra-strong, ultra-tough, degradable cellulose-based composites for multi-stimuli responsive shape memory

Fabrication of ultra-strong, ultra-tough, sustainable, and degradable bio-based composites is urgently needed but remains challenging. Here, a biomimetic sustainable, degradable, and multi-stimuli responsive cellulose/PCL/Fe3O4 composite with ultra-strong mechanical strength and ultra-high toughness was developed. To prepare the proposed composites, the soft poly(ε-caprolactone) (PCL) side chain was grafted onto the rigid cellulose backbone, then the cellulose graft copolymer (EC-g-PCL) reacted with rigid hexamethylenediamine modified Fe3O4 nanoparticle (Fe3O4-NH2) to construct the crosslinking network using MDI-50 as a crosslinker. Given by the construction of crosslinking network and the “hard” and “soft” interactive structure, the composites showed ultra-strong mechanical strength (25.7 MPa) and ultra-high toughness (107.0 MJ/m3), and the composite specimen could lift a weight of approximately 21,200 times its mass. The composites also exhibited rapid degradation ability with high degradation efficiency. In addition, the composites showed excellent thermal responsive shape memory property with a shape recovery ratio above 96 %. Most importantly, the Fe3O4 nanoparticles endowed the composites with photothermal conversion property, the composites exhibited superior NIR light-triggered shape memory capability. The EC-g-PCL/Fe3O4 composites with ultra-strong mechanical strength and ultra-high toughness have promising applications in heavy-lift, object transportation, and self-tightening knots.

Removal and Degradation of Microplastics Using the Magnetic and Nanozyme Activities of Bare Iron Oxide Nanoaggregates.

Removal and degradation of microplastics are often carried out separately. In this work, hydrophilic bare Fe3 O4 nanoaggregates allowed efficient removal of the most common microplastics including high-density polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyethylene terephthalate. Full extraction was achieved using Fe3 O4 at 1 % of the mass of microplastics. Hydrogen bonding is the main force for the adsorption of Fe3 O4 . Unlike the more commonly used hydrophobically modified Fe3 O4 nanoparticles, the bare Fe3 O4 benefitted from the peroxidase-like activity of its exposed surface, enabling further catalytic degradation of microplastics with nearly 100 % efficiency and easy recovery of the Fe3 O4 .

Removal and Degradation of Microplastics Using the Magnetic and Nanozyme Activities of Bare Iron Oxide Nanoaggregates

AbstractRemoval and degradation of microplastics are often carried out separately. In this work, hydrophilic bare Fe3O4 nanoaggregates allowed efficient removal of the most common microplastics including high‐density polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyethylene terephthalate. Full extraction was achieved using Fe3O4 at 1 % of the mass of microplastics. Hydrogen bonding is the main force for the adsorption of Fe3O4. Unlike the more commonly used hydrophobically modified Fe3O4 nanoparticles, the bare Fe3O4 benefitted from the peroxidase‐like activity of its exposed surface, enabling further catalytic degradation of microplastics with nearly 100 % efficiency and easy recovery of the Fe3O4.

The extraction of polycyclic aromatic hydrocarbons from water samples with aromatic-dithiocarbamate modified magnetic nanoparticles.

Considering the urgent need for the analysis of trace-level pollutants in water samples, the pre-concentration of micropollutants in water samples has been the focus of extensive research. Among current pretreatment methods, the solid phase extraction (SPE) technique has received enormous attention because of its low cost, ease of operation and high efficiency. In this work, a new adsorbent (Fe3O4@Au@DTC NPs) was acquired through modification of Fe3O4 nanoparticles (NPs) with gold (Au) and dithiocarbamate (DTC). To investigate their application ability, the adsorbent were utilized as an SPE adsorbent to enrich polycyclic aromatic hydrocarbons in water (PAHs, fluoranthene, pyrene, benzo anthracene, benzo fluoranthene, benzo pyrene). The obtained Fe3O4@Au@DTC NPs were confirmed by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and UV-Vis spectrum. Under optimal conditions, the calibration curves were obtained in the range of 10-500 ng L-1, while the limit of detection (LOD) ranged in 1.17-2.31 ng L-1. Furthermore, 50 mg of Fe3O4@Au@DTC NPs could extract trace PAHs from 500 mL real water samples into 1 mL eluent, and the spiked recoveries of five PAHs in river water and tap water reached 72-106% with relative standard deviations varying between 3.3-5.18%. Through the conversion of amines into DTC, we acquire desiring group modified Fe3O4 NPs, which showed great prospects in magnetic solid-phase extraction sphere and environmental field.

Exploiting CMC@Fe3O4 nanoparticles as a multi-functional component for hydrogel fabrication

Hydrogels have been widely applied in the fields of biology, medicine, soft materials and flexible/wearable devices owing to their superior biocompatibility and their versatile physicochemical properties. Although multiple chemical and physical methods have been proposed to functionalize hydrogels, endowing hydrogels with multi-properties/functionalities utilizing few components is still a challenge. This paper describes a simple and effective method to functionalize polymeric hydrogels with carboxymethyl cellulose (CMC) modified Fe3O4 nanoparticles (CMC@Fe3O4 NPs). The as-prepared metallogels exhibit good self-healing ability, ionic conductivity, photo-thermal transformability and magnetic field responsiveness. A triple functional sensor was built up to prove the universal viability of this metallogel toward functional devices.

Changes of physico-chemical properties of nano-biomaterials by digestion fluids affect the physiological properties of epithelial intestinal cells and barrier models

BackgroundThe widespread use of nano-biomaterials (NBMs) has increased the chance of human exposure. Although ingestion is one of the major routes of exposure to NBMs, it is not thoroughly studied to date. NBMs are expected to be dramatically modified following the transit into the oral-gastric-intestinal (OGI) tract. How these transformations affect their interaction with intestinal cells is still poorly understood. NBMs of different chemical nature—lipid-surfactant nanoparticles (LSNPs), carbon nanoparticles (CNPs), surface modified Fe3O4 nanoparticles (FNPs) and hydroxyapatite nanoparticles (HNPs)—were treated in a simulated human digestive system (SHDS) and then characterised. The biological effects of SHDS-treated and untreated NBMs were evaluated on primary (HCoEpiC) and immortalised (Caco-2, HCT116) epithelial intestinal cells and on an intestinal barrier model.ResultsThe application of the in vitro SDHS modified the biocompatibility of NBMs on gastrointestinal cells. The differences between SHDS-treated and untreated NBMs could be attributed to the irreversible modification of the NBMs in the SHDS. Aggregation was detected for all NBMs regardless of their chemical nature, while pH- or enzyme-mediated partial degradation was detected for hydroxyapatite or polymer-coated iron oxide nanoparticles and lipid nanoparticles, respectively. The formation of a bio-corona, which contains proteases, was also demonstrated on all the analysed NBMs. In viability assays, undifferentiated primary cells were more sensitive than immortalised cells to digested NBMs, but neither pristine nor treated NBMs affected the intestinal barrier viability and permeability. SHDS-treated NBMs up-regulated the tight junction genes (claudin 3 and 5, occludin, zonula occludens 1) in intestinal barrier, with different patterns between each NBM, and increase the expression of both pro- and anti-inflammatory cytokines (IL-1β, TNF-α, IL-22, IL-10). Notably, none of these NBMs showed any significant genotoxic effect.ConclusionsOverall, the results add a piece of evidence on the importance of applying validated in vitro SHDS models for the assessment of NBM intestinal toxicity/biocompatibility. We propose the association of chemical and microscopic characterization, SHDS and in vitro tests on both immortalised and primary cells as a robust screening pipeline useful to monitor the changes in the physico-chemical properties of ingested NBMs and their effects on intestinal cells.