Fe3O4 NP Research Articles

Magnetite Nanoparticle Assemblies and Their Biological Applications: A Review.

Magnetite nanoparticles (Fe3O4 NPs) have garnered significant attention over the past twenty years, primarily due to their superparamagnetic properties. These properties allow the NPs to respond to external magnetic fields, making them particularly useful in various technological applications. One of the most fascinating aspects of Fe3O4 NPs is their ability to self-assemble into complex structures. Research over this period has focused heavily on how these nanoparticles can be organized into a variety of superstructures, classified by their dimensionality-namely one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) configurations. Despite a wealth of studies, the literature lacks a systematic review that synthesizes these findings. This review aims to fill that gap by providing a thorough overview of the recent progress made in the fabrication and organization of Fe3O4 NP assemblies via a bottom-up self-assembly approach. This methodology enables the controlled construction of assemblies at the nanoscale, which can lead to distinctive functionalities compared to their individual counterparts. Furthermore, the review explores the diverse applications stemming from these nanoparticle assemblies, particularly emphasizing their contributions to important areas such as imaging, drug delivery, and the diagnosis and treatment of cancer.

Green synthesis of metal nanoparticles from Codium macroalgae for wastewater pollutants removal by adsorption

AbstractAlgae have adsorption properties and reducing agents due to their rich content. In this study, palladium nanoparticles (Pd NP), platinum nanoparticles (Pt NP), and iron oxide nanoparticles (Fe3O4 NP) were prepared from Codium macroalgae using green synthesis. The structure of the synthesized nanoparticles was elucidated by X‐ray diffractometry, Fourier transforms infrared spectroscopy, Brunauer–Emmett–Teller analysis, transmission electron microscopy, ultraviolet‐visible spectroscopy and scanning electron microscopy‐energy dispersive X‐ray spectrometry and their use as nanoadsorbents for the removal of pollutants from aqueous media was investigated in detail. Naproxen (NPX), an anti‐inflammatory drug, and the dyes methylene blue (MB) and cresol red (CR) were selected as pollutants for this study. Batch adsorption experiments were conducted using both real wastewater obtained from the Organised Industrial Zone of Isparta Province and synthetic water samples prepared with tap water from Burdur Province and pure water. Under optimum adsorption conditions, Pd NP showed significant efficiency in the real wastewater sample, with an adsorption capacity of 37.19 and 50.03 mg g–1 for CR and NPX, respectively, within 150 min. In comparison, Pt NP showed an adsorption capacity of 40.01 mg g–1 for MB within the same timeframe. These findings indicate that while Pd NP showed the highest adsorption capacity for both CR and NPX, Pt NP showed the highest adsorption capacity for MB. The Langmuir model and the pseudo‐second‐order equation were more suitable to describe the adsorption behavior of CR, MB, and NPX. In addition, studies on the desorption and reusability of the nanoadsorbents were carried out under the same optimum experimental conditions.

Inhibition of biofilm, quorum-sensing, and swarming motility in pathogenic bacteria by magnetite, manganese ferrite, and nickel ferrite nanoparticles.

Resistance to antibiotics by pathogenic bacteria constitutes a health burden and nanoparticles (NPs) are being developed as alternative and multipurpose antimicrobial substances. Magnetite (Fe3O4 np), manganese ferrite (MnFe2O4 np) and nickel ferrite (NiFe3O4 np) NPs were synthesized and characterized using thermogravimetric analysis, transmission electron microscopy, Fourier transformed infra-red, and X-ray diffraction. The minimal inhibitory concentrations (MIC) ranged from 0.625 to 10mg/mL against gram-positive (Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212), gram-negative (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853) and candida (Candida albicans ATCC 10239 and Candida tropicalis ATCC 13803) species. The NPs exhibited violacein inhibition against Chromobacterium violaceum CV12472 of 100% at MIC and reduced to 27.2%±0.8% for magnetite NPs, 12.7%±0.3% for manganese ferrite NPs and 43.1%±0.2% for nickel ferrite NPs at MIC/4. Quorum-sensing (QS) inhibition zones against C. violaceum CV026 were 12.5±0.6mm for Fe3O4 np, 09.1±0.5mm for MnFe3O4 NP and 17.0±1.2mm for NiFe3O4 np. The NPs inhibited swarming motility against P. aeruginosa PA01 and biofilm against six pathogens and the gram-positive biofilms were more susceptible than the gram-negative ones. The NiFe2O4 np had highest antibiofilm activity against gram-positive and gram-negative bacteria as well as highest QS inhibition while Fe3O4 NP had highest biofilm inhibition against candida species. The synthesized magnetic NPs can be used in developing anti-virulence drugs which reduce pathogenicity of bacteria as well as resistance.

Investigating the transport and colloidal behavior of Fe3O4 nanoparticles in aqueous and porous media under varying solution chemistry parameters.

The possible adverse effects of engineered iron oxide nanoparticles, especially magnetite (Fe3O4 NP), on human health and the environment, have raised concerns about their transport and behavior in soil and water systems. Accumulating these NPs in the environment can substantially affect soil and water quality and the well-being of aquatic and terrestrial organisms. Therefore, it is essential to examine the factors that affect Fe3O4 NP transportation and behavior in soil and water systems to determine their possible environmental fate. In this work, experiments were conducted in aqueous and porous media using an environmentally relevant range of pH (5, 7, 9), ionic strength (IS) (10, 50, 100 mM), and humic acid (HA) (0.1, 1, 10 mg L-1) concentrations. Fe3O4 NPs exhibited severe colloidal instability at pH 7 (⁓ = pHPZC) and showed an improvement in apparent colloidal stability at pH 5 and 9 in aquatic and terrestrial environments. HA in the background solutions promoted the overall transport of Fe3O4 NPs by enhancing the colloidal stability. The increased ionic strength in aqueous media hindered the transport by electron double-layer compression and electrostatic repulsion; however, in porous media, the transport was hindered by ionic compression. Furthermore, the transport behavior of Fe3O4 NPs was investigated in different natural waters such as rivers, lakes, taps, and groundwater. The interaction energy pattern in aquatic systems was estimated using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. This study showed the effects of various physical-chemical conditions on Fe3O4 NP transport in aqueous and porous (sand) media.

Propelling Multi-Modal Therapeutics of PEEK Implants through the Power of NO evolving Covalent Organic Frameworks (COFs).

The design and fabrication of NO-evolving core-shell nanoparticles (denoted as NC@Fe), comprised of BNN6-laden COF@Fe3 O4 nanoparticles, are reported. This innovation extends to the modification of 3D printed polyetheretherketone scaffolds with NC@Fe, establishing a pioneering approach to multi-modal bone therapy tailored to address complications such as device-associated infections and osteomyelitis. This work stands out prominently from previous research, particularly those relying on the use of antibiotics, by introducing a bone implant capable of simultaneous NO gas therapy and photothermal therapy (PPT). Under NIR laser irradiation, the Fe3 O4 NP core (photothermal conversion agent) within NC@Fe absorbs photoenergy and initiates electron transfer to the loaded NO donor (BNN6), resulting in controlled NO release. The additional heat generated through photothermal conversion further propels the NC@Fe nanoparticles, amplifying the therapeutic reach. The combined effect of NO release and PPT enhances the efficacy in eradicating bacteria over a more extensive area around the implant, presenting a distinctive solution to conventional challenges. Thorough in vitro and in vivo investigations validate the robust potential of the scaffold in infection control, osteogenesis, and angiogenesis, emphasizing the timeliness of this unique solution in managing complicated bone related infectious diseases.

Fabrication of a simple and sensitive mitoxantrone electrochemical sensor based on topdown recycling of iron wool and tissue paper

The development of rapid, sensitive detection and quantification techniques for mitoxantrone is crucial for monitoring treatment, cancer research and pharmaceutical analysis. In this context, The aim was to research an electrochemical sensor with a cheaper source of electrode material through recycling. The current study successfully recycled domestically used iron wool and tissue paper wastes into functional electrode materials: iron oxide nanoparticles (Fe3O4 NP) and black carbon (BC). The synthesis of BC was achieved by completely charring used tissue paper in sulphuric acid followed by ultrasonic disintegration. Also, Fe3O4 NP was synthesised through a simple, rapid rusting of iron chippings with hydrogen peroxide. The current research is the first to report this synthetic approach to obtain iron oxide and black carbon composite. The materials were then mixed to produce nanocomposite Fe3O4 NP:BC. Cyclic voltammetry and differential pulse voltammetry were used to study the behaviour of the modified electrodes towards the drug. The result showed the combination of the two materials in a Fe3O4 NP:BC = 1:2 ratio improved the active surface area of the glassy carbon electrode and conferred superior electrocatalytic properties compared to the individual materials. The Fe3O4 NP:BC modified electrode was highly sensitive towards mitoxantrone with a linear range of 5 × 10−6 to 1.0 × 10−4 M and a detection limit of 2.55 × 10−10 M. The current electrode's detection limit is lower than all but one of the electrodes reported for the drug whiles being the simplest and cheapest.

Thermal Fabrication of Magnetic Fe3O4 (Nanoparticle)@Carbon Sheets from Waste Resources for the Adsorption of Dyes: Kinetic, Equilibrium, and UV–Visible Spectroscopy Investigations

Thermal treatment is applied for the direct conversion of palm stalk waste to Fe3O4 (np)@carbon sheets (Fe3O4 (np)@CSs). The effect of conversion temperature was investigated. The TEM examination of the prepared magnetic Fe3O4 (np)@CSs showed the formation of Fe3O4 (np) in a matrix of carbon sheets as a coated layer with surface functional groups including carbonyl and hydroxyl groups. Removal of dyes such as methyl orange, methylene blue, and neutral red was achieved using fabricated Fe3O4 (np)@CSs which were prepared at 250 °C, 400 °C, and 700 °C in a weak acidic medium. By studying the contact time effect for the adsorption of methylene blue, neutral red, and methyl orange, using the fabricated Fe3O4 (np)@CSs which were prepared at 250 °C and 400 °C, equilibrium occurred between 120 min and 180 min. In addition, the first-order and second-order kinetic models were applied to the adsorption data. The results revealed that the adsorption data fit better with the second-order kinetic model. Furthermore, the Freundlich model was found to be more suitable for describing the process of the separation of the dyes onto Fe3O4 (np)@CSs which were prepared at 250 °C and 400 °C, suggesting heterogenous surfaces and multi-layer adsorption.

Magnetic delivery and ultrasound-responsive release of chelating microcapsules for selective removal of urolithiasis.

A novel urolithiasis treatment in which a chelating solution encapsulated in poly(lactic-co-glycolic acid); PLGA-based microcapsules was delivered magnetically to specific urolithiasis sites and then subjected to ultrasound (US) to release the chelating solution and dissolve the stones. Using a double-droplet microfluidics method, a hexametaphosphate (HMP) chelating solution was encapsulated in an Fe3O4 nanoparticle (Fe3O4 NP)-loaded PLGA polymer shell with a thickness of <15 μm, forming homogenous microcapsules of 319 ± 14 μm in size. The obtained microcapsules (HMP/Fe3O4@PLGA) exhibited efficient magnetic mobility and US-responsive solution release. Moreover, in a Ψ-shaped flow chip, selective delivery of HMP from the microcapsules was achieved with high magnetic delivery efficiency (>90%), and an effective removal efficacy (>95%, 7 repeat cycles) of artificial calcium oxalate (5 mm in size) via a chelating effect. Eventually, the potential removal of urolithiasis in the body was verified using a PDMS-based kidney urinary flow-imitating chip with a human kidney stone (CaOx 100%, 5-7 mm in size) located in the minor calyx under an artificial urine counter flow (0.5 mL min-1). In the end, more than 50% of the stone, even in surgically tricky regions, was removed by 10 repeated treatments. Therefore, the selective approach of stone-dissolution capsules will help to develop alternative urolithiasis treatments to conventional surgical and systemic dissolution approaches.

Extracellular matrix sheet modified with VEGF-loaded nanoparticles for bladder regeneration

Extracellular matrix (ECM) bioscaffolds have been widely studied to repair bladder tissue defects; however, insufficient angiogenesis and weak mechanical strength limit their applicability for tissue regeneration. In this work, ECM bioscaffolds were derived from decellularized sheets and then modified with vascular endothelial growth factor (VEGF)-conjugated superparamagnetic iron oxide nanoparticles (Fe3O4 NP–VEGF) to promote angiogenesis. Electrospun silk fibroin (SF) is a natural biocompatible protein with excellent mechanical properties. To further improve the mechanical properties of ECM bioscaffolds, SF was added to the Fe3O4 NP–VEGF-modified ECM bioscaffolds to develop a biomimetic ECM-like proangiogenic scaffold. In vitro characterization with endothelial cells revealed that the proangiogenic scaffold supports cell adhesion and proliferation. Furthermore, the biomimetic proangiogenic scaffold significantly accelerated vascularization in vivo in a rat bladder augmentation model. Importantly, these improvements in vascularization promoted urothelium and smooth muscle regeneration. These findings demonstrate that the developed biomimetic proangiogenic scaffold possesses great potential for bladder regeneration applications.

Alkyl gallate derived magnetic clusters and photothermal controlled release lipid carrier

In this study, hydrophobic driving formation of Fe3O4 nanoparticle clusters for photothermal controlled release was developed employing alkyl gallate. The identities and structures of the clustered Fe3O4 nanoparticles were investigated by FT-IR and SEM. The light absorption spectra unveiled strong absorption of Fe3O4 NP clusters from UV to NIR region (200–1424 nm). Incorporation of Fe3O4 nanoparticle clusters into a temperature-sensitive cocoa butter carrier realized efficient photothermal controlled release of the loaded curcumin under near-infrared (808 nm) irradiation. The strong photothermal effect could be attributed to the small absorption band gap of the Fe3O4 nanoparticle clusters owing to the π conjugation enlargement effect of alkyl gallates. Further investigations in yeast cell model revealed good biocompatibility of the Fe3O4 nanoparticle clusters and validity of photothermal release treatment of oxidative stress. The established strategies of construction of magnetic clusters and solid lipid carrier will facilitate photothermal controlled release of bioactives in food industry.

Corrosion resistant coating with passive protection and self-healing property based on Fe3O4-MBT nanoparticles

This work synthesized novel Fe3O4 nanoparticles loaded with 2-mercaptobenzothiazole corrosion inhibitors (Fe3O4-MBT NPs), which possessed not only photothermal conversion property but also corrosion inhibition ability. The loading percentage of MBT inhibitors in the Fe3O4-MBT NPs was 9.69 wt.%. The obtained Fe3O4-MBT NPs were incorporated into a shape memory epoxy coating to achieve passive protection and self-healing property. The passive protection property of intact Fe3O4-MBT/epoxy coating was assessed using electrochemical impedance spectroscopy (EIS) measurement during immersion in 3.5 wt.% NaCl solution. The low-frequency impedance modulus at 0.01 Hz of the composite coating containing 3 wt.% Fe3O4-MBT NPs was approximately 5 times higher than that of the blank epoxy coating after 240 h of immersion, indicating the superior barrier property of the composite coating. As for the self-healing property, the scratch width on the coating surface could narrow from 80 µm to ∼5 µm after near-infrared (NIR) light irradiation for 30 s, which was ascribed to the excellent photothermal conversion property of Fe3O4 NPs. EIS results verified that both the scratch closure triggered by the photothermal conversion of Fe3O4 NP and the release of MBT inhibitors are beneficial for the suppression of corrosion activity within the coating scratch. The Fe3O4-MBT/epoxy coating with outstanding passive protection and self-healing property holds great potential to achieve long-term corrosion protection.

PCL/Col I-based magnetic nanocomposite scaffold provides an osteoinductive environment for ADSCs in osteogenic cues-free media conditions

BackgroundThe bone tissue engineering (BTE) approach has been introduced as an alternative to conventional treatments for large non-healing bone defects. Magnetism promotes stem cells' adherence to biocompatible scaffolds toward osteoblast differentiation. Furthermore, osteogenic differentiation media are expensive and any changes in its composition affect stem cells differentiation. Moreover, media growth factors possess a short half-life resulting in the rapid loss of their functions in vivo. With the above in mind, we fabricated a multilayered nanocomposite scaffold containing the wild type of Type I collagen (Col I) with endogenous magnetic property to promote osteogenesis in rat ADSCs with the minimum requirement of osteogenic differentiation medium.MethodsFe3O4 NPs were synthesized by co-precipitation method and characterized using SEM, VSM, and FTIR. Then, a PCL/Col I nanocomposite scaffold entrapping Fe3O4 NPs was fabricated by electrospinning and characterized using SEM, TEM, AFM, VSM, Contact Angle, tensile stretching, and FTIR. ADSCs were isolated from rat adipose tissue and identified by flow cytometry. ADSCs were loaded onto PCL/Col I and PCL/Col I/Fe3O4-scaffolds for 1–3 weeks with/without osteogenic media conditions. The cell viability, cell adhesion, and osteogenic differentiation were evaluated using MTT assay, SEM, DAPI staining, ALP/ARS staining, RT-PCR, and western blotting, respectively.ResultsSEM, VSM, and FTIR results indicated that Fe3O4 was synthesized in nano-sized (15–30 nm) particles with spherical-shaped morphology and superparamagnetic properties with approved chemical structure as FTIR revealed. According to SEM images, the fabricated magnetic scaffolds consisted of nanofiber (500–700 nm). TEM images have shown the Fe3O4 NPs entrapped in the scaffold's fiber without bead formation. FTIR spectra analysis confirmed the maintenance of the natural structure of Col I, PCL, and Fe3O4 upon electrospinning. AFM data have shown that MNPs incorporation introduced stripe-like topography to nanofibers, while the depth of the grooves has decreased from 800 to 500 nm. Flow cytometry confirmed the phenotype of ADSCs according to their surface markers (i.e., CD29 and CD105). Additionally, Fe3O4 NP improved nanocomposite scaffold strength, wettability, porosity, biocompatibility and also facilitates the ALP activity, calcium-mineralization. Finally, magnetic nanocomposite scaffolds upregulated osteogenic-related genes or proteins’ expression (e.g., Col I, Runx2, OCN, ON, BMP2) in seeded ADSCs with/without osteo-differentiation media conditions.ConclusionsTogether, these results indicate that Fe3O4 NPs within the natural structure of Col I increase osteogenic differentiation in osteogenic cues-free media conditions. This effect could be translated in vivo toward bone defects healing. These findings support the use of natural ECM materials alongside magnetic particles as composite scaffolds to achieve their full therapeutic potential in BTE treatments.Graphical

Facile synthesis and high-performance dielectric properties of polyethylene oxide-chitosan- iron oxide nano-composite for electrical applications

The use of polymer mixtures to create ternary nanocomposites with customized features is receiving greater attention around the world. Polyethylene oxide/chitosan/iron oxide NPs form a novel ternary nanocomposite in our research. In one step, iron oxide nanoparticles were produced using laser ablation at various times and distributed in a PEO/CS. XRD, FTIR, FESEM, and UV–Vis methods were used to study the produced PEO/CS/Fe3O4 NPs films. The produced samples' dielectric characteristics and electrical conductivity were measured. The XRD data showed a significant reduction in crystallinity, which enhanced Fe3O4 NP interactions with the PEO/CS matrix. The size of the Fe3O4 NPs created by laser ablation is 45 nm. At varied laser ablation times, FT-IR measurements confirm the specific interaction in PEO/CS/Fe3O4. The FESEM images show that the distribution of Fe3O4 NPs has appeared as bright spots on the surfaces of the samples. The optical characteristics of the produced materials provide an absorption edge at 218 nm, which was shifted to a high wavelength via raising the laser ablation time. The energy gap of nanocomposite samples decreased as laser ablation time increased, ranging from 5.35 eV to 4.43 eV for the direct transition and from 4.91 eV to 2.49 eV for the indirect transition. With an increase in Fe3O4 NPs, A.C electrical conductivity of PEO/CS/Fe3O4 samples increased. The PEO/CS/Fe3O4 NPs at 20 min laser ablation time achieve a high conductivity of ∼8.47 × 10−6 S/cm. The study showed that PEO/CS/Fe3O4 samples have good electrical characterization, which may motivate the use of these nanocomposites in varied electrical applications.

A novel Fe 3 O 4 magnetic nanoparticles functionalized by glutamic acid and conjugated with thiosemicarbazide alter the expression of norB gene, in Staphylococcus aureus

Here, the improved efficacy of a novel composite of iron oxide (Fe3O4) magnetic nanoparticles (MNPs) functionalized by glutamic acid (Glu) and conjugated with thiosemicarbazide (TSC), evaluated on the expression of norB efflux pump gene in S. aureus strains. The proper synthesis of Fe3O4@Glu–TSC NP was confirmed and characterized by Fourier transform infrared spectroscopy (FTIR), scanning and transmission electron microscopy, Brunauer–Emmett–Teller (BET), energy dispersive X-Ray spectroscopy (EDX), X-ray diffraction (XRD), and UV–vis spectroscopy. The effect of NP on the expression of norB gene was studied using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The physical analysis of NP revealed proper synthesis, dispersion, and stability, as well as the spherical/cubic morphology with a mean size of 35–60 nm. The minimum inhibitory concentration (MIC) value of the functionalized nanoparticle decreased by two folds towards each respected strain in contrast with the Fe3O4 NP (alone). Additionally, in the presence of NP, the norB gene expression was reduced by up to 50% in comparison with the control group. In conclusion, the functionalized NP can be considered as a promising inhibitor of bacterial efflux pump genes against antibiotic-resistant bacteria. However, further studies should be conducted to determine the safety of these nanoparticles for medicinal applications.

Highly Efficient Electrogenerated Chemiluminescence Quenching on Lipid-Coated Multifunctional Magnetic Nanoparticles for the Determination of Proteases.

This work reports a highly efficient electrogenerated chemiluminescence (ECL) quenching on lipid-coated multifunctional magnetic nanoparticles (MMNP) for the determination of proteases incorporating membrane-confined quenching with a specific cleavage reaction for the first time. A new ruthenium complex [Ru(bpy)2(ddcbpy)](PF6)2 (bpy = 2,2'-bipyridine, ddcbpy = 4,4'-didodecyl-carbonyl-2,2'-bipyridine with two hydrophobic long alkyl chains) was synthesized as a signal probe, while [cholesterol-(CH2)6-HSSKLQK(peptide)-ferrocene (quencher)] was designed as a specific peptide-quencher probe. The MMNP were prepared by inserting both the signal probe and the peptide-quencher probe into the cholesterol-phospholipid-coated Fe3O4 magnetic nanoparticles (Fe3O4 NP, ∼200 nm). When prostate specific antigen (PSA) taken as a model analyte was introduced into the suspension of MMNP, PSA cleaved the amide bond of SK in cholesterol-(CH2)6-HSSKLQK-Fc, and then the cleaved peptide-motif-Fc-quencher was deviated from the MMNP, resulting in the increase in the ECL intensity. It was found that the ECL quenching constant of [Ru(bpy)2(ddcbpy)]2+ on MMNP (KSV,NP/lipECL =2.68 × 107 M-1) is 137-folds higher than that on the lipid-coated electrode (KSV,lipECL=1.95 × 105 M-1) and 391-folds higher than that in the solution (KSV,aqECL =6.86 × 104 M-1). The ECL emission of Ru(bpy)32+ derivative-attached Fe3O4 NP was observed at ∼1.2 V, involving the tunnel-electron transfer pathway (TPA• + Ru(bpy)33+ = Ru(bpy)32+*). Based on the highly efficient ECL quenching of the ruthenium complex by ferrocene on the MMNP, a new ECL method was developed for PSA with a linear range from 0.01 to 1.0 ng/mL and a limit of detection of 3.0 pg/mL. This work demonstrates that the approach of ECL quenching by ferrocene on lipid-coated Fe3O4 NP is promising and could be easily extended to determine other proteases.

Insight into the influence of morphology and structure of Fe3O4 nanoparticles on demulsification efficiencies

Functional Fe3O4 nanoparticle (Fe3O4 NP) is one of the most attractive candidates in the demulsification field because of its outstanding recycling ability, low cytotoxicity, and good biocompatibility. However, the lack of research on their interfacial properties greatly inhibits further development in the industrial demulsification process. The main aim of this work is to explore interfacial properties of functional Fe3O4 NPs from their intrinsic natures, namely morphologies and structures. Three Fe3O4 NPs with different morphologies, including triangle-shaped Fe3O4 NPs (TF NPs), octahedron-shaped Fe3O4 NPs (OF NPs) and truncated octahedron-shaped Fe3O4 NPs (TOF NPs), were prepared by using the solvothermal reaction. Their demulsification capacities of water-in-cyclohexane (W/C) emulsion were evaluated and the TOF NPs had best performance. The demulsification process including diffusion, adsorption and phase separation stages of these Fe3O4 NPs were investigated in detail by interfacial experiments and mathematical models for explain the demulsification result. The diffusion coefficient was calculated at both the early and late stages of the demulsification process, along with their adsorption energy and the elastic modulus of oil-water interfaces. TOF NPs had the largest diffusion coefficient of 1.777 × 10−6 and 2.443 × 10−6 m2/s at the early and late stages, respectively. The W/C interface adsorption energy of TOF NPs were much lower than that of the others and the elastic modulus of W/C interface reduced by TOF NPs was also more effective than that by the others.

Recent Breakthroughs and Advancements in NOx and SOx Reduction Using Nanomaterials-Based Technologies: A State-of-the-Art Review.

Nitrogen and sulpher oxides (NOx, SOx) have become a global issue in recent years due to the fastest industrialization and urbanization. Numerous techniques are used to treat the harmful exhaust emissions, including dry, traditional wet and hybrid wet-scrubbing techniques. However, several difficulties, including high-energy requirement, limited scrubbing-liquid regeneration, formation of secondary pollutants and low efficiency, limit their industrial utilization. Regardless, the hybrid wet-scrubbing technology is gaining popularity due to low-costs, less-energy consumption and high-efficiency removal of air pollutants. The removal/reduction of NOx and SOx from the atmosphere has been the subject of several reviews in recent years. The goal of this review article is to help scientists grasp the fundamental ideas and requirements before using it commercially. This review paper emphasizes the use of green and electron-rich donors, new breakthroughs, reducing GHG emissions, and improved NOx and SOx removal catalytic systems, including selective/non-catalytic reduction (SCR/SNCR) and other techniques (functionalization by magnetic nanoparticles; NP, etc.,). It also explains that various wet-scrubbing techniques, synthesis of solid iron-oxide such as magnetic (Fe3O4) NP are receiving more interest from researchers due to the wide range of its application in numerous fields. In addition, EDTA coating on Fe3O4 NP is widely used due to its high stability over a wide pH range and solid catalytic systems. As a result, the Fe3O4@EDTA-Fe catalyst is projected to be an optimal catalyst in terms of stability, synergistic efficiency, and reusability. Finally, this review paper discusses the current of a heterogeneous catalytic system for environmental remedies and sustainable approaches.

Remote Spatiotemporal Control of a Magnetic and Electroconductive Hydrogel Network via Magnetic Fields for Soft Electronic Applications.

Multifunctional hydrogels are a class of materials offering new opportunities for interfacing living organisms with machines due to their mechanical compliance, biocompatibility, and capacity to be triggered by external stimuli. Here, we report a dual magnetic- and electric-stimuli-responsive hydrogel with the capacity to be disassembled and reassembled up to three times through reversible cross-links. This allows its use as an electronic device (e.g., temperature sensor) in the cross-linked state and spatiotemporal control through narrow channels in the disassembled state via the application of magnetic fields, followed by reassembly. The hydrogel consists of an interpenetrated polymer network of alginate (Alg) and poly(3,4-ethylenedioxythiophene) (PEDOT), which imparts mechanical and electrical properties, respectively. In addition, the incorporation of magnetite nanoparticles (Fe3O4 NPs) endows the hydrogel with magnetic properties. After structural, (electro)chemical, and physical characterization, we successfully performed dynamic and continuous transport of the hydrogel through disassembly, transporting the polymer–Fe3O4 NP aggregates toward a target using magnetic fields and its final reassembly to recover the multifunctional hydrogel in the cross-linked state. We also successfully tested the PEDOT/Alg/Fe3O4 NP hydrogel for temperature sensing and magnetic hyperthermia after various disassembly/re-cross-linking cycles. The present methodology can pave the way to a new generation of soft electronic devices with the capacity to be remotely transported.

Manufacture of high sensitive Ag-Fe3O4-PDMS nanocomposite pressure sensor through morphology control of conductive filler

Silver nanowire (AgNW) has been proposed as a promising conductive filler candidate based on its excellent electrical and thermal conductivity properties. However, residual PVP (polyvinylpyrrolidone) exists on the surface of AgNW synthesized through the polyol process. As a result, there is a problem in that the contact resistance (RC) is increased. This problem can be solved by improving the contact area between AgNWs. Therefore, in this study, the electrical conductivity characteristics of AgNW were to be improved by etching which can increase the contact area of AgNW. The concentration of etchant was adopted as the main parameter, and ideal etching parameter was derived by analyzing the microstructure and electrical conductivity characteristics of the etched AgNW. The etched AgNW showed a minimum resistance of 0.034 kΩ/□, and the etched AgNW showed about 23% improved surface area compared to the as-prepared AgNW. In addition, by controlling the ultrasonic milling parameters, it was intended to produce Fe3O4 nanoparticles (Fe3O4 NP) that make the conductive structure less dense and prevent stacking between AgNWs by acting as a nano-spacer. The prepared Fe3O4 NP showed an average particle size distribution of 150 nm or less. Ag-Fe3O4-PDMS (Polydimethylsiloxane) nanocomposite was prepared through such a conductive filler. As a result of analyzing the response characteristics of Ag-Fe3O4-PDMS nanocomposite, the resistance decreased linearly as the applied pressure increased, and the root-mean-square was 0.99 or higher.

Dual-recognition colorimetric sensing of thrombin based on surface-imprinted aptamer-Fe3O4.

Thrombin plays an essential role in blood coagulation and some physiological and pathological processes. The convenient, rapid, sensitive, and specific detection of thrombin is of great significance in clinical research and diagnosis. Herein, surface molecularly imprinted polymer (MIP) was modified on aptamer-functionalized Fe3O4 nanoparticles (MIP-aptamer-Fe3O4 NP) for thrombin colorimetric assay by taking advantage of the peroxidase-like activity of Fe3O4 NP. With the adsorption of thrombin into imprinted cavities, the exposed surface area of Fe3O4 NP decreased, causing a decrease in its peroxidase-like activity toward 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. On the other hand, the reductive amino acids on the thrombin surface also impeded the oxidation of TMB. Both phenomena caused the light blue color of the sensing solution. Thus, a specifically sensitive colorimetric approach for the visual detection of thrombin was proposed with a linear range and limit of detection of 108.1 pmol L-1-2.7 × 10-5 mol L-1 and 27.8 pmol L-1, respectively. Moreover, due to the double recognition elements of MIP and aptamer, the prepared MIP-aptamer-Fe3O4 NP showed higher selectivity to thrombin than that based on only one recognition element. It is worth noting that no special property (e.g. electrochemical or fluorescence activity) of the template was required in this work. Thus, more template molecules can be easily, selectively, and sensitively detected based on the proposed MIP-aptamer-mimic enzyme colorimetric sensing strategy.