Fe3O4 Magnetic Nanoparticles Research Articles

Efficient PEGylated magnetic nanoniosomes for co-delivery of artemisinin and metformin: a new frontier in chemotherapeutic efficacy and cancer therapy

Two strategies were employed to modify the performance of the nano-niosome drug delivery system. Initially, the surface of the nano-niosomes underwent modification through the inclusion of polyethylene glycol, thereby altering its properties. Additionally, the core of the nano-niosomes was equipped with Fe3O4 magnetic nanoparticles to impart magnetic characteristics to the system. This study presents the development of PEGylated magnetic nanoniosomes (PMNios) for the co-delivery of artemisinin (ART) and metformin (MET) in cancer therapy, highlighting significant advancements in chemotherapeutic efficacy. The magnetization of the nano-niosomes facilitated the targeted delivery of drugs to specific tissues, while PEGylation improved the bioavailability of the nano-niosomes. These PEGylated magnetic niosomes (PMNios) were then loaded with artemisinin and metformin drugs. The synthesized PMNios were thoroughly evaluated in terms of zeta potential, size, morphology, and entrapment efficiency. The PMNios achieved a drug loading efficiency of 88%. They exhibited an average size of 298 nm, a polydispersity index of 0.32, and a zeta potential of − 19 mV, indicating the complete stability. SEM and TEM images of the PMNios revealed a spherical morphology. Subsequently, the PMNios were compared with other forms of nano-niosomes, including empty niosomes, non-magnetic niosomes, and non-PEGylated niosomes. The encapsulation of the nano-niosomes with magnetic nanoparticles allows for faster delivery of the encapsulated drugs to the tumor site, while PEGylation improved the stability, bioavailability, and controlled release of the PMNios. Furthermore, the in-vitro effectiveness of various formulations of the PMNios against A549, a lung cancer cell line, demonstrated that the PMNios exhibited appropriate toxicity towards cancer cell lines in the presence of an external magnetic field. Gene expression level of Bcl2 were lower for the PMNios-ART-MET system, whereas the level of Bax were higher than the other group. The PMNios-ART-MET system also demonstrated well internalization into the A549 cells and preponderant endocytosis. These findings underscore the novelty and potential of PMNios as a robust platform for the targeted co-delivery of hydrophilic and hydrophobic drugs, promising a new frontier in cancer therapy by enhancing the therapeutic index and minimizing side effects.

High Stability and Reusability of Papain Immobilized on the Non‐Toxic Magnetic Dialdehyde Starch Nanoparticles

AbstractPapain is widely used in food, drug, and bioactive peptide production and must be immobilized onto carriers with biocompatibility. Dialdehyde starch (DAS) can be a good biocompatible cross‐linker according to its active aldehyde groups. In the present study, the magnetic nanoparticles dialdehyde starch (MDASN), synthesized by DAS and Fe3O4 magnetic nanoparticles (Fe‐MNP), are successfully used to immobilize papain to improve the enzymic activity. The structure and morphology of DAS, MDASN, and immobilized papain onto magnetic dialdehyde starch nanoparticles (papain‐MDASN) are characterized detailly. The morphology of DAS is like a flat ball, and that of Fe‐MNP and papain‐MDASN are spherical and clumpy. The particle size of Fe‐MNP and papain‐MDASN are small, resulting in a large surface electrostatic effect and partial agglomeration. Enzymic activity studies of papain‐MDASN exhibit that the immobilized papain on MDASN represents better temperature resistance, alkaline resistance, thermal stability, and reusability, and its activity recovery is up to 68.21%. Papain onto magnetic dialdehyde starch nanoparticles (MDASN) may enhance its potential application in production processes.

Improving enzyme immobilization: A new carrier-based magnetic polymer for enhanced covalent binding of laccase enzyme

In the quest for effective enzyme immobilization methods, this study focuses on synthesizing carrier-based magnetic polymer to enhance the covalent binding of T. versicolor laccase. Utilizing chitosan (CS) and alginate (ALG) composites, modified with Fe3O4 magnetic nanoparticles (MNPs), we aimed to improve the enzyme's stability, reusability, and performance under varying conditions. The ionic gelation method was employed to prepare CS-ALG and CS-ALG-Fe3O4 MNPs composites, resulting in an 84 % and 91 % immobilization efficiency. The immobilized enzyme demonstrated superior thermal stability, retaining 48 % activity for CS-ALG-laccase and 67 % for CS-ALG-Fe3O4 MNPs-laccase at 70 °C, compared to 29 % for the free enzyme. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the composites, revealing significant morphological changes and successful enzyme integration. Kinetic studies indicated that immobilization increased the Vmax to 141 μmol/min for CS-ALG-laccase and 111 μmol/min for CS-ALG-Fe3O4 MNPs-laccase, while slightly reducing substrate affinity (Km) to 1.42 mM−1 and 1.32 mM−1, respectively. The immobilized laccase retained higher activity after ten reaction cycles (81 % activity for CS-ALG-Fe3O4 MNPs-laccase) and during prolonged storage (75 % activity retention), showcasing its potential for industrial applications. Additionally, the enzyme exhibited increased resistance to various organic solvents, enhancing its practical utility.

Removal, mechanistic and kinetic studies of Cr(VI), Cd(II), and Pb(II) cations using Fe3O4 functionalized Schiff base chelating ligands.

The Schiff base chelating ligands; (E)-2-(3,3-dimethoxy-2-oxa-7,10-diaza-3-silaundec-10-en-11-yl)phenol (L1), (E)-N-(2-((pyridine-2ylmethylene)amino)ethyl)-3-(trimethoxysilyl)propan-1-amine (L2) and (E)-N-(2-((thiophen-2-ylmethylene)amino)ethyl)-3-(trimethoxysilyl)propan-1-amine (L3) were immobilized on Fe3O4 magnetic nanoparticles (MNPs) and utilized in the extraction of Cr(VI), Cd(II) and Pb(II) metal cations from aqueous solutions. The compounds synthesized, denoted as L1@ Fe3O4, L2@Fe3O4, and L3@Fe3O4, were characterized using FT-IR spectroscopy, TEM-SEM, VSM, and BET/BHJ techniques for analysis of functional groups, surface morphology, magnetic properties, and degree of porosity of the adsorbents, respectively. BET/BHJ technique confirmed the mesoporous nature of the compounds as their pore diameters ranged between 15 and 17nm. The initial optimization conditions of pH, adsorbent dosage, initial metal concentration, and contact time on adsorption were studied using L1@ Fe3O4. The optimum efficiencies recorded were 68% and 46% for Cr(VI) and Cd(II), respectively, obtained at pH 3, and a metal concentration of 20ppm while an efficiency of 99% was recorded for Pb(II) cations at pH 7 and a metal concentration of 100ppm. Compounds L2@Fe3O4 and L3@ Fe3O4 were also used in the extraction of metal cations from aqueous solution and gave efficiencies of 22%, 56%, and 78% for L2@ Fe3O4 and 19%, 90%, and 59% using L3@ Fe3O4 for Cr(VI), Cd(II), and Pb(II), respectively. The maximum adsorption capacities of L1@ Fe3O4 for Cr(VI), Cd(II), and Pb(II) cations were obtained from the Langmuir isotherm as 32.84, 41.77, and 450.45mg/g, respectively. The experimental data was analyzed using pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Elovich kinetic models. Both linear and non-linear forms of kinetic isotherms; Langmuir, Freundlich, Redlich-Peterson, and Temkin were utilized to investigate the nature of adsorption on L1@Fe3O4. The mechanistic studies deduced that the Langmuir isotherm and pseudo-second-order kinetic model better described the adsorption process both yielding high correlation coefficient values (R2 > 0.98).

Immobilization of laccase on Fe3O4@SiO2 core@shell magnetic nanoparticles for methylene blue biodegradation

Here we report the preparation and characterization of novel enzyme supports based on silica-coated Fe3O4 magnetic nanoparticles. These nanomaterials were modified at their outer silica surface with isocyanate, trimethylammonium and β-cyclodextrin moieties to immobilize laccase from Trametes versicolor through covalent, electrostatic and supramolecular interactions, respectively, with protein immobilization yields ranging from 21.7% to 53.5%. The effect of the immobilization approach on the activity, optimal working conditions, stability and reusability of the resulting biocatalysts were studied. Best results were achieved for native and adamantane-modified laccase supramolecularly immobilized on β-cyclodextrin bearing supports in terms of their catalytic properties, showing 18.0 U and 14.0 U of immobilized laccase activity per gram of support. However, high thermal stability was observed for the enzyme covalently immobilized on isocyanate-modified nanoparticles, with 14.8-fold increase in the half-life time at 65ºC in comparison with native laccase. Best reusability properties were also achieved by covalent immobilization, retaining over 88% of the initial catalytic activity after 13 cycles of magnetic reuses. All enzyme derivatives were evaluated for the catalytic degradation of methylene blue as pollutant model, showing significant reduction of the dye. In special, a 68-fold increase in the removal efficacy was observed for covalently immobilized enzyme compared to the free laccase. These results suggest high potential application of these biocatalysts in wastewater treatment.

Fe3O4@SiO2‐APA‐Amide/Imid‐NiCl2 as a New Nano‐Magnetic Catalyst for the Synthesis of 4H‐Pyrimido[2,1‐b]benzothiazole Derivatives via MCRs Under Solvent‐Free Conditions

AbstractThis study presents the synthesis and characterization of a novel nano‐magnetic catalyst, Fe3O4@SiO2‐APA‐amide/imid‐NiCl2, designed for the efficient production of 4H‐pyrimido[2,1‐b]benzothiazole derivatives under environmentally friendly, solvent‐free conditions. The catalyst combines magnetic Fe3O4 nanoparticles with a silica shell and functionalized amide and imidazole groups, which enhance its catalytic activity and stability. By optimizing the reaction conditions, we achieved high yields of the target compounds while minimizing the environmental impact. The catalyst's magnetic properties facilitate easy separation and recovery, making it an attractive option for sustainable organic synthesis. The successful synthesis of the catalyst was confirmed through comprehensive characterization techniques, including X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results demonstrate that Fe3O4@SiO2‐APA‐amide/imid‐NiCl2 is a highly effective and reusable catalyst for the environmentally friendly synthesis of biologically relevant pyrimido[2,1‐b]benzothiazole derivatives, contributing to the advancement of green methodologies in organic chemistry.

Development of photoelectrochemical immunosensor based on halide perovskite protected by organometallic compounds for determining interleukin-17A (IL-17A).

The overexpression of interleukin-17A (IL-17A) is closely associated with the pathogenesis of autoimmune diseases and cancer, rendering precise identification of IL-17A level critical for disease diagnosis and prognosis monitoring. In this study, CsPbBr3 nanoclusters (NCs) were embedded in C16H14Br2O6Pb2 organometallic compound (Pb-MA MOC) via a hot injection approach. Through this way, the issue of CsPbBr3 NCs susceptible to decomposition in water was solved, and the photocurrent intensity that isgenerated by CsPbBr3 was significantly enhanced. A highly sensitive photoelectrochemical (PEC) sensor for detecting IL-17A in human serum was developed using CsPbBr3/Pb-MA as the photoactive material. The electrode was initially modified with CsPbBr3/Pb-MA. Then, antibody-modified Fe3O4 magnetic nanoparticles (MNs) with target analyte IL-17A captured, and IL-17A antibody-modified Au@CuNi diatomic catalyst (DAC) formed sandwich immune complex structure on theelectrode. The existence of CuNi DAC led to a substantial reduction in photoelectric signal intensity due to oxidation of ascorbic acid in thesupporting electrolyte. The photocurrent intensity exhibited linear correlation with IL-17A concentration within the range 15-750pg/mL, and achieving an impressive detection limit of1pg/mL. Moreover, the sensor was successfully applied to the determination of IL-17A in human serum, suggesting its potential clinical applications.

Murexide retention and antibacterial performance of semiconductor copolymer/magnetic iron oxide hybrid nanocomposites synthesized via one pot in-situ chemical oxidative polymerization

Herein, semiconductor-magnetic hybrid nanocomposites, poly(vanillin-co-thiophene)/magnetic iron oxide (PVTO-Fe3O4), were successfully synthesized via single-step in situ chemical oxidative polymerization in the presence of different weight percentages of magnetic iron oxide nanoparticles Fe3O4 NPs (3, 6, and 9 wt%). Whereas the Fe3O4 NPs were prepared via an environmentally friendly, modified co-precipitation method, and their physicochemical characteristics were comprehensively analyzed using various analytical techniques. The adsorption behavior of the resulting samples towards murexide dye in aqueous solutions was investigated, along with their antibacterial efficacy against both gram-positive (Staphylococcus aureus and Bacillus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. The adsorption study revealed that the nanocomposite containing 9 wt% Fe3O4 NPs achieved the highest removal efficiency for MX (approximately 87.41 %) and exhibited a maximum adsorption capacity of approximately 100.7 mg/g, surpassing many adsorbents reported in the literature. Optimization experiments identified the optimal conditions as 40 mg of adsorbent dose, 40 mL of MX solution (125 mg/L), pH 5, and 160 min contact time. The adsorption kinetics followed pseudo-second-order kinetics, and the adsorption isotherm fitted well with the Freundlich model. Moreover, the nanocomposite was efficiently recovered from the solution using an external magnet, highlighting its potential for practical applications. Antibacterial testing revealed significant antibacterial effectiveness of PVTO and its nanocomposites against both gram-positive and gram-negative bacteria, with a minimum inhibition zone of 20 mm.

Enhanced Cancer Biomarker Detection using Fe3O4 Magnetic Nanoparticles: Synthesis, Surface Modifications and Diagnostic Applications: A Review

Fe3O4 magnetic nanoparticles exhibit significant potential for cancer detection due to their unique magnetic properties and versatility. This review examines their role in enhancing cancer biomarker detection, focusing on synthesis methods, surface modifications and diagnostic accuracy. Fe3O4 nanoparticles serve as sensitive MRI contrast agents, facilitating early cancer diagnosis and improving patient prognosis. Synthesis techniques influence their properties, morphology and dimensions, which affect performance. Surface modifications enhance targeting and reduce immunological reactions, enabling precise biomarker detection and effective drug delivery to tumours, minimizing damage to healthy tissue. Despite these advantages, challenges remain in optimizing delivery efficiency and overcoming medication resistance. Further research is required to understand the pharmacokinetics and pharmacodynamics of these nanoparticles, including their distribution, metabolism and physiological impacts. This review provides insights into the potential of Fe3O4 magnetic nanoparticles as cancer detection agents, aiming to guide future research towards developing safer and more efficient applications in medical diagnostics and treatment. HIGHLIGHTS Fe3O4 magnetic nanoparticles exhibit unique magnetic properties that are highly effective in detecting cancer biomarkers. These nanoparticles enable early cancer diagnosis by identifying biomarkers at low concentrations with high sensitivity. The review assesses various synthesis techniques for Fe3O4 magnetic nanoparticles to optimize their detection capabilities. Exploration of surface modification strategies to enhance the functionality and efficacy of Fe3O4 nanoparticles in cancer biomarker detection. Enhanced diagnostic accuracy through the application of Fe3O4 magnetic nanoparticles, promising improved outcomes in cancer detection technologies. GRAPHICAL ABSTRACT

Recoverable and reusable light-induced multi-arm azobenzenes-Fe3O4 hybrid sorbent for enrichment of phthalate plasticizer and utilized as a SALDI substrate for the detection of 2-naphthol

The construction, structural identifications along with compositional properties, using TEM, FT-IR, and XPS spectroscopies, of an innovative light-induced multi-arm azobenzenes based Fe3O4 magnetic nanoparticles (Azo-Fe3O4 MNPs) are being reported. Such organic (light-sensitive dendrimers-like structure), inorganic (magnet core), hybrid material has been applied as an efficient recoverable/reusable extractive sorbent for the detection of phthalate plasticizers from acetate buffer solution. The extraction study was controlled within consecutive procedures via UV-light exposure to achieve pore-size control which then further subjected for the evaluation of the analytes’ retention, separation, and release as well as the detection of the phthalate pollutants using GCMS–. Various experimental conditions, such as time of extraction, salt concentration, pH, and desorption time, were studied and adjusted. Additionally, the extraction repeatability (RSD from 0.46 % to 6.12%, n = 5) of the studied sorbent was comparable to other published work. The linear range extended from 6.25 to 100 μg L-¹ and detection limits (LOD) within the range of 41- 150 ng L-1 were achieved, demonstrating good linearity with values ranging from 0.9992 to 0.9892. The inter-batch and intra-batch RSD ranged from 0.46 % to 6.12 %, respectively. Additionally, it provides effective detection of 2-naphthol when used as a SALDI substrate.

Determination of three dechloranes in environmental water by magnetic solid-phase extraction-gas chromatography-negative chemical ionization mass spectrometry based on the covalent organic framework material

Dechloranes are additive-type chlorine flame retardants that are widely used in processing industrial products, such as electronic equipment and textiles. Dechloranes, which can enter the human body through various routes, pose significant health risks because of their toxicity, persistence, and bioaccumulation. In 2023, dechlorane plus was listed in the Stockholm Convention on Persistent Organic Pollutants. In the same year, China recognized this compound as a priority-controlled substance. Dechloranes are commonly found at trace levels in water, which is extremely harmful to the environment and human health. Therefore, the development of detection methods for dechloranes is crucial. Magnetic solid-phase extraction (MSPE) has attracted considerable attention because of its low organic solvent consumption, simplicity of adsorbent separation, and ease of operation. In general, the selectivity and efficiency of MSPE depend on the characteristics of the adsorbent. Covalent organic frameworks (COFs) have regular porosity, structural predictability and stability, high specific surface areas, and adjustable pore sizes, which are advantageous for a wide range of separation and analysis applications. In this study, Fe3O4 magnetic nanoparticles and a COF material (TpBD) were combined to prepare Fe3O4@TpBD as an adsorbent for dechloranes. Subsequently, an effective method for analyzing dechlorane in environmental water was established by coupling MSPE with gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS). The successful synthesis of Fe3O4@TpBD was confirmed using transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometry. A single-factor method was used to optimize the extraction conditions, including the Fe3O4@TpBD dosage, pH of water sample, elution solvent type and volume, extraction time, elution time, and ionic strength. The target analytes were separated on a TG-5SILMS column (30 m×0.25 mm×0.25 μm) and quantified using the external standard method in the selected-ion monitoring (SIM) mode. Under the optimal extraction conditions, the method validation results showed a linear range of 2-1000 ng/L. The limits of detection (LODs) and quantification (LOQs) were 0.18-0.27 ng/L and 0.60-0.92 ng/L, respectively, for the three analytes. The intra-day and inter-day precisions at three spiked levels were 4.2%-16.2% and 6.9%-15.7%, respectively. This method was successfully applied to the determination of dechloranes in environmental water samples (laboratory tap water, reservoir water, wastewater treatment plant effluent, and landfill leachate treatment effluent). The recoveries of the three dechloranes at different spiked levels ranged from 77.8% to 113.3% with relative standard deviations (RSDs) of 2.5%-16.3% (n=3). With the advantages of operational simplicity, high sensitivity, and good reproducibility, the proposed method is suitable for the qualitative and quantitative determination of dechloranes in environmental water.

Construction and Characterization of Magnetic Fe3O4 Nanoparticles Supported Palladium Complex: Research on Synthesis of Aryl Nitriles and Tetrazoles

Construction and Characterization of Magnetic Fe3O4 Nanoparticles Supported Palladium Complex: Research on Synthesis of Aryl Nitriles and Tetrazoles

Magnetic solid-phase extraction of amoxicillin and doxycycline from water and urine samples based on cetylpyridinium chloride-modified Fe3O4 nanoparticles followed by spectrophotometric determination.

This research describes an easy, rapid, and inexpensive magnetic solid-phase extraction (MSPE) approach employing Fe3O4 magnetic nanoparticles modified with cetylpyridinium chloride (Fe3O4@CPC/MNPs) for extracting amoxicillin (AMX) and doxycycline (DOX) after derivatization with 4-chloroaniline as a color reagent. The azo-coupling of AMX and DOX with the color reagent in the alkaline medium caused yellow and yellow-orange azo dyes with maximum absorption wavelengths of 435 and 438 nm, respectively. The UV-Vis spectroscopy was utilized to determine the target analyte after the extraction procedure. Good linearities (R2 > 0.99) in the concentration ranges of 0.03-4.50 and 0.05-6.00µg/mL were obtained for AMX and DOX, respectively. The experimental detection limits of AMX and DOX were obtained as 0.01 and 0.02 µg/mL, respectively. The developed approach was effectively applied to pre-concentrate and quantify AMX and DOX in environmental water and urine samples.

Continuous flow synthesis of MOF UTSA-16(Zn), mixed-metal and magnetic composites for CO2 capture – toward scalable manufacture

UTSA-16(Zn) is a zinc and citrate-based metal-organic framework (MOF) which has shown highly promising performance for CO2 capture. However, the transition of this MOF to industrial application has been hindered as a scalable synthesis method has not yet been reported. Herein we report the first scalable continuous flow synthesis of UTSA-16(Zn), demonstrating a production rate of 173 g/h, which is a 77-fold increase compared to previously reported batch methods. Sustainability of the synthesis was maximised using low-cost non-toxic reagents and a low-energy flow reactor operating at atmospheric pressure. Chemical (reactant ratios, Zn/Mg mixed-metal) and process parameters (solvent ratio, flow rate, temperature) were optimised to continuously produce UTSA-16(Zn) which also demonstrated a high CO2 adsorption capacity up to 3.8 mmol/g and conversion yield of up to 66 %. Pristine MOFs are typically thermally insulating, thus thermal regeneration is challenging. To overcome this limitation, magnetic nanoparticles can be embedded within the MOF. This enables fast and energy efficient regeneration through magnetic induction heating. Here, citrate-coated Fe3O4 magnetic nanoparticles (MNP-CA) were successfully incorporated into the flow synthesis process of UTSA-16(Zn) to form UTSA-16(Zn)@MNP-CA magnetic framework composites (MFCs), representing the highest production rate reported of any MFC to date (152 g/h c.f. 13 g/h for MgFe2O4@UiO-66-NH2). UTSA-16(Zn)@MNP-CA MFCs demonstrate rapid heating under a magnetic field (26–150 °C in 60 s). The flow method developed herein is also widely applicable for scalable manufacture of other MOFs and MFCs, enabling their broader transition towards industrial applications.

The solid-solution HxPO4@Fe3O4 synthesized by irradiation enhances the adsorption capacity of tungsten(VI) and anti-interference of coexisting oxoanion in waste water: Surface oxolation interaction

Tungsten (W), mainly existing as hexavalent oxidation state in nature, has been considered as an increasingly prominent waterborne pollutant, but it is also a critical metal. Therefore, it is important to develop a material to adsorb W(VI) from the waste water containing W(VI) to realize the high-efficiency enrichment and recovery of W(VI). Inspired by self-assembly of phosphate and W(VI) ions in the acidic solutions to form phosphotungstic polyoxoanions (e.g., Keggin-type PW12O403−), in this work, we have loaded the phosphate ion to surface of the magnetic Fe3O4 nanoparticles (Fe3O4 NPs) by β particle irradiation to synthesize a composite adsorbent, HxPO4@Fe3O4 solid-solution (SS). This novel adsorbent is very efficient for W(VI) adsorption and recovery. The results of a batch of adsorption experiments indicate that HxPO4@Fe3O4 SS has a high adsorption efficiency for W(VI) in aqueous environments and strong anti-interference of coexist ions especially PO43−. Under room temperature conditions (∼25 °C), the maximum adsorption capacity reaches 88.44 mg g−1. This method not only ensures a substantial increase in W(VI) adsorption but also provides a facile means for adsorbent recovery, while minimizing additional environmental burdens. Based on the characterization results from Fourier transform infrared, Zeta potential, and X-ray photoelectron spectroscopies, we speculated that the possible mechanism of the adsorption process is that formed W(VI) polyoxoanions in acidic solutions are initially attracted by electrostatic attraction to the positively charged HxPO4@Fe3O4 surface, and then oxolation reaction occurs between W-OH of polyoxoanions and phosphate hydroxyl (P-OH) on the HxPO4@Fe3O4 surface to form P-O-W bridging oxygen group. This adsorption mechanism is also reflected in the adsorption kinetics, following a pseudo-second-order kinetic model, and adsorption thermodynamics, exhibiting a large enthalpy change (−76.3 kJ/mol) and a significant entropy reduction (−174.5 J/(mol K)).

Fe3O4 magnetic nanoparticles (MNPs) as an efficient catalyst for allylic oxidation of chromenes to coumarins with TBHP

Synthesis of coumarins via allylic oxidation of 2H-chromenes using the Fe3O4 magnetic nanoparticles (MNPs) in combination with tert‑butyl hydroperoxide (TBHP) as an oxidant is reported. This strategy is straightforward and performed at mild and economical reaction conditions. The process environmentally benign, versatile, and efficiently converting various chromenes into coumarins, which are compounds of interest in the pharmaceutical industry due to their wide range of biological activities.

Modified magnetic Nano-Biocomposite as friendly environmental catalyst for rapid degradation of organic dyes and selective aerobic oxidation of cyclohexene through advance oxidation process

To eliminate contaminated organic matter from water and wastewater, a stable, recyclable, and environmentally friendly nano-biocomposite was designed. The magnetic Fe3O4 nanoparticles were functionalized by SiO2/N-2-(aminoethyl)-3-aminopropyl/glutaraldehyde/chitosan/Cobalt to fabricate nano-biocomposite (FS-(Am/g/Cs)@CoNPs). The morphological/structural identification of nano-biocomposite was carried out by ICP-OES, DR-UV, XRD, FE-SEM, TEM, HR-TEM, BET, EDX, FT-IR, TGA, and VSM techniques. The catalytic performance of this heterogeneous catalyst was studied in the degradation of organic dyes including methylene blue, methyl orange, methylene violet, and Bisphenol A, and efficiency was achieved at 99.3 % (kobs = 0.3703 min−1), 97.4 % (kobs = 0.3627 min−1), 93.6 % (kobs = 0.228 min−1) and 98.8 % (kobs = 0.459 min−1) after 12–14 min at room temperature in pH = 7.0, respectively. The reaction proceeded through the activation of Co2+/Co3+ which occurs on the surface of the FS-(Am/g/Cs)@CoNP by the PMS/O2 system through recombination of SO4•- and OH•. Furthermore, selective allylic oxidations of cyclohexene to cyclohexenone (TOF = 4583.7 h−1, 100 % selectivity, 98 % conversion) were done by this nano-biocomposite.

Development of a Fast and Efficient Strategy Based on Nanomagnetic Materials to Remove Polystyrene Spheres from the Aquatic Environment

Microplastics contamination is growing globally, being a risk for different environmental compartments including animals and humans. At present, some Spanish beaches and coasts have been affected by discharges of these pollutants, which have caused a serious environmental problem. Therefore, efficient strategies to remove microplastics (MPs) from environmental samples are needed. In this study, the application of three magnetic materials, namely iron oxide (Fe3O4) and the composites Fe3O4@Ag and Fe3O4@Ag@L-Cysteine, to remove MPs, specifically polystyrene (PS), from water samples has been assessed. The magnetic nanoparticles were synthesized and characterized by field effect scanning electron microscopy with energy dispersive X-ray spectroscopy detection (FESEM-EDX). Experimental conditions such as temperature, time, and pH during the removal process were assessed for the different adsorbent materials. The removal rate was calculated by filtering the treated water samples and counting the remaining MPs in the water using ImageJ software. The strongest removal efficiency (100%) was shown using Fe3O4@Ag@L-Cysteine for PS at 50 mg L−1 within 15 min of the separation process at room temperature and a neutral pH. A thermodynamic study demonstrated that the developed MPs elimination strategy was a spontaneous and physisorption process. Coated Fe3O4 magnetic nanoparticles were demonstrated to be an efficient adsorbent for MP removal in aquatic environments and their use a promising technique for the control of MPs contamination.

Development of amphiphilic hypercrosslinked porous polymers for magnetic extraction of multiple environmental pollutants in water

Under the principle of similar compatibility, researchers have developed various polarity extractants corresponding to a class of chemicals. Separating different polarities chemicals with one extractant effectively has become a novel research trend in separation science. Given the complexity of environmental sample matrices and the significant differences in polarity and solubility of various compounds, the introduction of hydrophilic groups to hydrophobic material skeletons can lead to sorbents with hydrophilic-lipophilic balance (HLB) property and thus improve their extraction performance for substances with different polarities. In this work, a hypercrosslinked polymer (HCPPz-TPB), designated as HLB, was synthesized by incorporating polar pyrazine and nonpolar triphenylbenzene molecules within each other. Subsequently, a core-shell magnetic composite material was obtained by encapsulating magnetic Fe3O4 nanoparticles in HCPPz-TPB. The material was applied as an adsorbent for magnetic solid phase extraction (MSPE) and combined with a high-performance liquid chromatography-photodiode array detector (HPLC-PDA) to enrich, separate, and detect seven polar contaminants in environmental water samples. The proposed approach, Fe3O4@SiO2@HCPPz-TPB−MSPE-HPLC-PDA, is characterized by its outstanding high sensitivity, low detection limits, wide linear range, and good reproducibility. The method demonstrated satisfactory linearity in the range of 0.05–2 μg mL-1 with R2 values between 0.9969 and 0.9997; the limits of detection (LOD) were observed to be within the range of 0.0019–0.016 μg L-1, and limits of quantification (LOQ) was observed to be within the range of 0.0064–0.054 μg L-1 range with good precision. The recoveries of the different contaminants in the environmental samples ranged from 83.61 to 116.46% (RSD≤10.56, n = 5). The new hydrophilic-lipophilic balance extractant is highly efficient, sensitive, and precise for extracting different polar pollutants. The findings demonstrate that the Fe3O4@SiO2@HCPPz-TPB display a remarkable affinity for multiple targets, driven by complex interactions including multi-stackings and hydrogen bonding as a sorbent. The synthesized Fe3O4@SiO2@HCPPz-TPB may be employed in diverse applications, including extraction, removal, and determination of diverse trace multi-target analytes in complex media.

Untethered & Stiffness‐Tunable Ferromagnetic Liquid Robots for Cleaning Thrombus in Complex Blood Vessels

AbstractThrombosis is a significant threat to human health. However, the existing clinical treatment methods have limitations. Magnetic soft matter is used in the biomedical field for years, and ferromagnetic liquids exhibit tunable stiffness and on‐demand movement advantages under magnetic fields. In this study, a ferromagnetic liquid robot (FMLR) is developed and applied it to thrombus removal in complex blood vessels. The FMLR consisted of Fe3O4 magnetic nanoparticles and dimethyl silicone oil. The FMLR can pass through a narrow complex maze through shape deformation by tailoring the intensity and direction of the external magnetic field. Finite element simulation analysis is used to validate the mechanism of controllable FMLR movements. Importantly, the storage modulus of FMLR can be tuned from 0.1 to 2018 Pa by varying the external magnetic intensity, ensuring its effectiveness in removing rigid and stubborn thrombi present on the vascular walls. Toward medical robotic applications, FMLR can be used in telerobotic neurointerventional. Experiments demonstrating the capability of FMLR to remove thrombi in the ear veins of rabbits are conducted. This study introduces an efficient approach for thrombus elimination, broadening the utilization of FMLRs within the realm of clinical medicine.