Magnetic Fe3O4 Chitosan Research Articles

Chitosan-iron oxide nanoparticle preparation and performance as a lipid-lowering agent in serum patients with nephrotic syndrome

Objective: The main objectives of this study was to Prepare and study the structural features of chitosan/iron oxide nanoparticles CS-FeO NPs and to examine the applications of chitosan nanoparticles as a lipid-lowering agent in children with nephrotic syndrome
 Method: The preparation processes for nanoparticles are described in depth. Chitosan nanoparticle applications are shown. X-ray diffraction patterns (XRD) indicated that the magnetic Fe3O4 nanoparticles were pure Fe3O4 with a spinel structure and the coating of chitosan did not result in a phase change.
 Results: The coating of CTS onto the Fe3O4 nanoparticles was also demonstrated by the measurement of Fourier transform infrared (FTIR) spectra. Magnetic measurement revealed that the saturated magnetization of the Fe3O4–chitosan nanoparticles reached +18.3 mV and the nanoparticles showed the characteristics of superparamagnetic.
 Conclusion: Magnetic Fe3O4–chitosan nanoparticles were prepared successfully by the covalent binding of CTS on the Fe3O4 nanoparticles. These microspheres was apply to the magnetic-field-assisted lipid lowering processes.

Green synthesis of sustainable magnetic nanoparticles Fe3O4 and Fe3O4-chitosan derived from Prosopis farcta biomass extract and their performance in the sorption of lead(II)

The sustainable processes are now in tremendous demand for nanomaterial synthesis as a result of their unique properties and characteristics. The magnetic nanoparticles comprised of Fe3O4 and its conjugate with abundant and renewable biopolymer, chitosan, were synthesized using Prosopis farcta biomass extract, and the resulting materials were used to adsorb Pb (II) from aqueous solution. Thermodynamic parameters revealed that the sorption of lead (II) on Fe3O4 as well as Fe3O4-Chitosan (Fe3O4-CS) has been an endothermic and self-regulating procedure wherein the sorption kinetics was defined by a pseudo-second-order pattern and the sorption isotherms corresponded to the Freundlich pattern. A multivariable quadratic technique for adsorption process optimization was implemented to optimize the lead (II) adsorption on Fe3O4 and Fe3O4-chitosan nanoparticles, the optimal conditions being pH 7.9, contact time of 31.2 min, initial lead concentration of 39.2 mg/L, adsorbent amount of 444.3 mg, at a 49.7 °C temperature. The maximum adsorption efficiencies under optimal conditions were found to be 69.02 and 89.54 % for Fe3O4 and Fe3O4-CS adsorbents, respectively. Notably, Fe3O4 and Fe3O4-CS can be easily recovered using an external magnet, indicating that they are a viable and cost-effective lead removal option.

Cobalt-Tetraamide-Phthalocyanine Immobilized on Fe3O4/Chitosan Microspheres as an Efficient Catalyst for Baeyer-Villiger Oxidation.

Cobalt-Tetraamide-Phthalocyanine (CoTaPc) immobilized onto magnetic Fe3O4 chitosan microspheres (Fe3O4/CTO) was synthesized via a simple immersion method, which is an efficient catalyst for the oxidation of cyclic ketones to lactones with O2/benzaldehyde as the oxidant. The CoTaPc-Fe3O4/CTO catalyst was applied for the first time in the Baeyer–Villiger (B–V) oxidation reaction. Characterization results obtained from X-ray diffraction, UV–vis, Fourier transform infrared, and scanning electron microscopy showed that the combination of CoTaPc and magnetic Fe3O4/CTO microspheres was achieved. The catalyst could be easily separated from the reaction system with an external magnet and reused several times without the remarkable loss of activity. In addition, a possible radical mechanism for the B–V oxidation in this catalytic system is proposed and verified by controlled experiments.

Magnetic Fe3O4-chitosan micro- and nanoparticles for wastewater treatment

ABSTRACTIn this study, first, magnetic nanoparticles (MNP) were synthesized using a coprecipitation method and the synthesized particles were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and vibrating sample magnetometry (VSM). According to DLS and VSM analyses results, it was seen that the size of the MNP was smaller than 10 nm and they exhibited superparamagnetic properties, respectively. Then, magnetic Fe3O4-chitosan micro/nanoparticles were synthesized using a suspension cross-linking method in the presence of the MNP. Fe3O4-chitosan microparticles (Fe3O4-CMs) and Fe3O4-chitosan nanoparticles (Fe3O4-CNs), which have different structural, morphological, and magnetic properties, were obtained. All of the particles were characterized using transmission electron microscopy (TEM), FTIR, TGA, DLS, and VSM. In the second part of the study, the dye adsorption properties of the two different adsorbents from aqueous solution were investigated. For these purposes, Bromothymol Blue (BB) was used as a dye and the parameters affecting adsorption of BB (contact time, initial dye concentration, temperature and pH) were investigated. When the optimum adsorption conditions were provided for each adsorbent, the adsorption capacities of Fe3O4-CNs and Fe3O4-CMs were 82.2 and 193.3 mg/g, respectively.

Tannase immobilisation by amino-functionalised magnetic Fe3O4-chitosan nanoparticles and its application in tea infusion

The tannase (from Aspergillus niger) was immobilised by glutaraldehyde conjugation to amino-functionalised chitosan-coated magnetic nanoparticles (Fe3O4-CS nanoparticles). Fourier-transform infrared spectroscopy and thermo-gravimetric analysis showed that chitosan was coated on the surface of magnetic nanoparticles. Transmission electron microscopy indicated that the synthesised nanoparticles (Fe3O4-CS) were almost spherical or ellipsoidal with an average diameter of 5.97 ± 1.25 nm. The stability and functionality of free and immobilised tannase were compared. Both forms of tannase exhibited the same optimal temperature of 30 °C, whereas the optimal pH value of immobilised tannase (pH 4.5) was lower than that of the free tannase (pH 5.5). The pH and thermal stabilities of immobilised tannase were significantly better than those of free tannase. Immobilised tannase retained over 50% of its initial activity after repeated utilisation for eight cycles. Furthermore, the immobilised tannase effectively improve the clarity and colour of black and green tea infusions. These results showed that amino-functionalised Fe3O4-CS nanoparticles are an efficient carrier for immobilising tannase, and immobilised tannase can be used in the clarification of tea infusion.

Magnetic chitosan/graphene oxide composite loaded with novel photosensitizer for enhanced photodynamic therapy.

Photodynamic therapy (PDT) is an increasingly recognized alternative to treat various cancers in clinical practice. Most second-generation photosensitizers (PS) are hydrophobic and have poor targeting selectivity, which limit their efficacy for PDT. In this paper, graphene oxide (GO) coupled with magnetic Fe3O4 nanoparticles and chitosan (CS) (MCGO) was prepared by a one-pot solvothermal method and used as a nanocarrier for loading the new photosensitizer HNPa (λmax = 698 nm), which was first synthesized by our group, and was considered as a good water-soluble drug and an excellent tissue-penetrating agent due to its strong absorption at 698 nm (near-infrared region). The synthesized composite (MCGO–HNPa) showed high stability, good water solubility and biocompatibility, expected magnetic targetability, and good photostability for PDT even in low concentrations. Our research reveals that MCGO nanomaterials can promote the production and release of singlet oxygen (ΦΔ = 62.9%) when compared with free HNPa. In addition, the in vitro cell uptake experiments suggested that the MCGO nanomaterials can accelerate the penetration of HNPa drugs into the tumor cell nucleus and that the drug release behavior is pH-sensitive. The MTT assay results against human hepatoma cell lines HepG-2 clearly show that the MCGO–HNPa composite can effectively result in cell damage and apoptotic cell death under light, and that the nanocomposite can improve the PDT antitumor effect of PS agents with negligible dark toxicity. Meanwhile, the research on the photoreaction mechanism reveals that Type I and Type II photodynamic reactions can occur simultaneously in this PDT process, and their relative contributions depend on the type and dose of the photosensitizer. Type II has a greater effect on PDT than Type I, especially for a higher HNPa photosensitizer dose. All the results reveal the promising application of the presented novel strategy.

Preparation and characterization of magnetic Fe3O4–chitosan nanoparticles for cellulase immobilization

Cellulase immobilization is an important issue for cellulose hydrolysis in bioethanol production. In this study, Fe3O4 nanoparticles were synthesized using a coprecipitation method and were coated with chitosan. Glutaraldehyde was used as cross-linking reagent for cellulase immobilization. The morphology, structure, and related physical and chemical properties of the supports were studied by X-ray diffraction, a physical property measurement system, Fourier transform infrared spectroscopy, and Transmission electron microscopy. Response surface methodology was used to determine the optimal cellulase loading efficiency (LE) and standard recovery ratio (RR). The verification tests show the immobilized particles had an LE of 99.6% and an RR value of 68.5%. It was found that immobilized cellulase had a wider range of adaptability to hydrolysis pH and temperature when compared with free cellulase. Five hydrolysis experiments demonstrated effective hydrolysis using immobilized cellulase while maintaining on average 80% of the free cellulase’s activity.

Enhanced Production of κ-Carrageenase and κ-Carrageenan Oligosaccharides through Immobilization of Thalassospira sp. Fjfst-332 with Magnetic Fe3O4-Chitosan Microspheres.

In this study, immobilized bacteria (IMB) microsphere was prepared by embedding κ-carrageenase-producing Thalassospira sp. Fjfst-332 (TF332) onto a magnetic Fe3O4-chitosan carrier. The performance of Fe3O4-chitosan carrier was optimized by comparing its bacteria immobilization capacity at different Fe3O4:chitosan ratios and temperatures, while the functions of IMB microspheres were characterized by examining their κ-carrageenase production at different temperatures, pH's, and reuse cycles. At the 1:1 (w:w) Fe3O4:chitosan ratio, the Fe3O4-chitosan carriers possessed sufficient anchoring capacity for bacterial immobilization without significant compromise of their magnetism for magnetic separation of IMB from culture media. The spectroscopic analysis of IMB microspheres indicated that the immobilization of TF332 might affect the amide groups in chitosan. Compared to free bacteria, IMB can produce κ-carrageenase at higher temperature, wider pH range, and faster rate. More importantly, the κ-carrageenase-producing activity was sustained for at least seven reuse cycles. The major κ-carrageenan degradation products of IMB-derived κ-carrageenase were the oligosaccharides containing two to six monosaccharide units. Overall, this Fe3O4-chitosan-TF-332 microsphere has the potential to become a stable and reusable platform for large-scale production of κ-carrageenan oligosaccharides.

Cobalt-Tetracarboxyl-Phthalocyanine Linked with Fe3o4/Chitosan Microsphereas—Efficient Catalyst for Dye Degradation

Cobalt-tetracarboxyl-phthalocyanine (CoTcPc) immobilized onto magnetic Fe3O4 chitosan microsphere (CoTcPc-chitosan/Fe3O4) was synthesized via a simple immersion method, and its performance on the degradation of organics (methylene blue) in the presence of air and fluorescent light was examined. Characterization results obtained from FT-IR and XPS showed that the combination of CoTcPc and magnetic Fe3O4 chitosan microsphere was achieved effectively by the coordination, hydrogen, and electrostatic adsorption bond. Moreover, the observed catalytic performance also revealed that the MB was removed entirely in 6 h with CoTcPc-chitosan/Fe3O4 as the catalyst. The stability and reusability were further evaluated, and results demonstrated that the catalyst remained active after the fourth reaction for in the same conditions. Moreover, the catalyst could be separated by an external magnet. Therefore, the CoTcPc-chitosan/Fe3O4 catalyst has potential application in the field of wastewater treatment. Cobalt-tetracarboxyl-phthalocyanine(CoTcPc) immobilized onto magnetic Fe3O4 chitosan microsphere (CoTcPc-chitosan/Fe3O4) was synthesized via a simple immersion method, and its performance on the degradation of organics (methylene blue) in the presence of air and fluorescent light was examined.

Spectroscopic method for the detection of 2,4-dichlorophenoxyacetic acid based on its inhibitory effect towards catalase immobilized on reusable magnetic Fe3O4-chitosan nanocomposite

A spectrometric approach for the sensitive detection of 2,4-dichlorophenoxyacetic acid (2.4-D) was developed based on the inhibitory effect of 2,4-D on the enzymatic activity of catalase. The magnetic Fe3O4-chitosan nanocomposites pre-activated with glutaraldehyde was used as support to improve the stability and reusability of catalase. After determination, the catalase-loaded Fe3O4-chitosan nanocomposites was separated from the reaction mixture using a magnet for repeat use. The activity assay of the immobilized catalase was based on the enzymatic decomposition of H2O2 which was monitored at 290nm. The activity of the immobilized catalase decreased in the presence of 2,4-D. This inhibition degree was proportional to the concentration of 2,4-D in the range of 0.045–2.5μM with a detection limit of 0.02μM. Possible inhibition mechanism of catalase by 2,4-D was deduced according to the variation of parameters and a mixed inhibition mechanism was observed. The developed method exhibited good stability, repeatability and reproducibility, which can be used as a promising new tool for the analysis of enzyme inhibitors.

Preparation and catalytic properties of magnetic rectorite-chitosan-Au composites

A novel composite was assembled by introducing magnetic Fe3O4 nanoparticles, chitosan and Au nanoparticles (AuNPs) on rectorite (REC) surfaces. The obtained REC-Fe3O4-CTS-Au composite was characterized and used as the catalyst to remove 4-nitrophenol (4-NP) and methyl orange (MO) from water in the presence of NaBH4. The large surface of REC and the abundant hydroxyl group of chitosan on REC surface could restrain the agglomeration of AuNPs. REC-Fe3O4-CTS-Au exhibited the superiority in catalytic efficiency. At the catalyst dosage of 150 mg/L, it took only 15 min for 0.2 mM 4-NP solution to reach complete reduction, and 30 min for 1.0 mM 4-NP solution. This catalyst had the higher catalytic activity for 4-NP than MO reduction. Moreover, the catalyst could be conveniently separated and recycled from the reaction mixtures using an external magnetic field, and reused for 4-NP (or MO) reduction in fourteen cycles with retaining the original 99% (or 95%) conversion efficiency. This work indicates that REC-Fe3O4-CTS-Au can be a promising catalyst for the highly efficient degradation of organic dyes.

Synthesis of Magnetic Fe3O4‐Chitosan Nanoparticles by Ionic Gelation and Their Dye Removal Ability

The aim of this study was to synthesize magnetic Fe3O4 chitosan nanoparticles (m-Fe3O4-CNs) by ionic gelation method and use them as adsorbent for the removal of Bromothymol Blue (BB) from aqueous solutions. Also, the effect of various parameters on the preparation of m-Fe3O4-CNs was investigated in this study. The nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy and vibrating sample magnetometry (VSM). Adsorption of BB on m-Fe3O4-CNs was studied in a batch reactor at different experimental conditions such as adsorbent dosage, pH, contact time, initial BB concentration and temperature. Kinetic behaviors, equilibrium isotherms and thermodynamics of the adsorption process were investigated in detail. The Langmuir adsorption isotherm model and pseudo-second-order kinetic model well fitted the adsorption experimental results. The thermodynamic parameters showed that the adsorption was a spontaneous, favorable and exothermic process in nature.

Preparation and characterization of magnetic Fe3O4–chitosan nanoparticles loaded with isoniazid

Abstract A novel and simple method has been proposed to prepare magnetic Fe 3 O 4 –chitosan nanoparticles loaded with isoniazid (Fe 3 O 4 /CS/INH nanocomposites). Efforts have been made to develop isoniazid (INH) loaded chitosan (CS) nanoparticles by ionic gelation of chitosan with tripolyphosphate (TPP). The factors that influence the preparation of chitosan nanoparticles, including the TPP concentration, the chitosan/TPP weight ratio and the chitosan concentration on loading capacity and encapsulation efficiency of chitosan nanoparticles were studied. The magnetic Fe 3 O 4 nanoparticles were prepared by co-precipitation method of Fe 2+ and Fe 3+ . Then the magnetic Fe 3 O 4 /CS/INH nanocomposites were prepared by ionic gelation method. The magnetic Fe 3 O 4 nanoparticles and magnetic Fe 3 O 4 /CS/INH nanocomposites were characterized by XRD, TEM, FTIR and SQUID magnetometry. The in vitro release of Fe 3 O 4 /CS/INH nanocomposites showed an initial burst release in the first 10 h, followed by a more gradual and sustained release for 48 h. It is suggested that the magnetic Fe 3 O 4 /CS/INH nanocomposites may be exploited as potential drug carriers for controlled-release applications in magnetic targeted drugs delivery system.

Chitosan decorated Fe3O4nanoparticles as a magnetic catalyst in the synthesis of phenytoin derivatives

In the present work, Fe3O4 nanoparticles were synthesized by the chemical coprecipitation process. Subsequently, the synthesized nanoparticles were modified with chitosan by a simple method and characterized by X-ray diffractometry (XRD), Fourier transform infrared spectrophotometry (FT-IR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Then, phenytoin derivatives were catalyzed by magnetic Fe3O4–chitosan nanoparticles. Fe3O4–chitosan nanoparticles were found to be a recoverable organocatalyst for the efficient synthesis of 5,5-diphenylhydantoins and 5,5-diphenyl-2-thiohydantoins from substituted benzils and urea or thiourea derivatives. The nanocatalyst could be recovered easily under a magnetic field for reuse, and considerable loss of its catalytic activity was not observed after reuse in seven consecutive runs.

Enzyme encapsulation in magnetic chitosan-Fe3O4 microparticles

Two simple procedures for the preparation of magnetic chitosan enzyme microparticles have been investigated and used for the immobilisation of endophytic fungus Cercospora kikuchii lipase as model enzyme. In the first case, lipase was entrapped in Fe3O4-chitosan microparticles by cross-linking method, while in the second case magnetic immobilised derivatives were produced using spray drying. Immobilised enzymes showed high enzyme activity retention and stability during storage without significant loss of activity. Glutaraldehyde Fe3O4-chitosan powders presented a higher lipase activity retention and storage stability than the others preparations. However, the immobilised derivatives produced by cross-linking showed higher enzyme activity after reuse cycles. The results proved that the magnetic Fe3O4-chitosan microparticles are an effective support for the enzyme immobilisation since the immobilised lipase showed best properties than the free form.

Optimized immobilization of peracetic acid producing recombinant acetyl xylan esterase on chitosan coated-Fe3O4 magnetic nanoparticles

Recombinant acetyl xylan esterase (rAXE) from Aspergillus ficcum, which mediated the production of peracetic acid (PAA), was covalently immobilized with magnetic Fe3O4–chitosan nanoparticles (Fe3O4–CSN) using glutaraldehyde. Fe3O4–CSN were prepared by co-precipitation of Fe2+ and Fe3+ ions in ammonia solution followed by coating of chitosan with sodium tripolyphosphate (TPP), and were characterized by FESEM, SEM, FTIR and XRD. The immobilization rAXE on Fe3O4–CSN was optimized using response surface methodology (RSM) by examining immobilization cross-linking time, enzyme concentration, and glutaraldehyde (GA) concentration. Based on the experimental values the predicted variables for the maximum immobilization of rAXE in terms of specific activity (0.042U) were found to be 13.65μg of rAXE protein and 0.265% of GA concentrations, where the optimum cross-linking time was 11.33h. The immobilized rAXE onto Fe3O4–CSN nanoparticles shows better stability at thermal and pH ranges than soluble free rAXE. The immobilized rAXE was stable for around 90% of activity in the aqueous phase, whereas it retains only 60% of its activity in the semi-aqueous phase after 10 cycles of reuse.

Ultrasound assisted the green synthesis of 2-amino-4H-chromene derivatives catalyzed by Fe3O4-functionalized nanoparticles with chitosan as a novel and reusable magnetic catalyst

Fe3O4 nanoparticles were prepared by chemical coprecipitation method. Subsequently immobilization of chitosan on Fe3O4 nanoparticles was accomplished and afforded magnetic Fe3O4-chitosan nanoparticles. Synthesized nanoparticles was found to be a magnetic and heterogeneous catalyst for a one-pot and efficient synthesis of 2-amino-4H-chromenes by condensation of aldehydes with malononitrile and resorcinol under ultrasound irradiation as an ecofriendly method. This convenient procedure allowed us to achieve products under ultrasound irradiation in short time and excellent yield without using of harmful catalyst. The present method will permit a further increase of the diversity within the 2-amino-4H-chromene family.

Evaluation of Fe(III)EDTA and Fe(II)EDTA-NO reduction in a NO x scrubber solution by magnetic Fe3O4-chitosan microspheres immobilized microorganisms

A two-stage bioreduction system containing magnetic-microsphere-immobilized denitrifying bacteria and iron-reducing bacteria was developed for the regeneration of scrubbing solutions for NO x removal. In this process, a higher bioreduction rate and a better tolerance of inhibition of bacteria were achieved with immobilized bacteria than with free bacteria. This work focused on evaluation of the effects of the main components in the scrubbing solution on Fe(III)EDTA (EDTA: ethylenediaminetetraacetate) and Fe(II)EDTA-NO reduction, with an emphasis on mass transfer and the kinetic model of Fe(III)EDTA and Fe(II)EDTA-NO reduction by immobilized bacteria. It was found that Fe(II)EDTA-NO had a strong inhibiting effect, but Fe(II)EDTA had no effect, on Fe(III)EDTA reduction. Fe(II)EDTA accelerated Fe(II)EDTA-NO reduction, whereas Fe(III)EDTA had no effect. This showed that the use of the two stages of regeneration was necessary. Moreover, the effect of internal diffusion on Fe(III)EDTA and Fe(II)EDTANO reduction could be neglected, and the rate-limiting step was the bioreduction process. The reduction of Fe(III)EDTA and Fe(II)EDTA-NO using immobilized bacteria was described by a first-order kinetic model. Bioreduction can therefore be enhanced by increasing the cell density in the magnetic chitosan microspheres.

Preparation and characterization of EDTAD-modified magnetic-Fe3O4 chitosan composite: application of comparative adsorption of dye wastewater with magnetic chitosan

Ethylenediaminetetraacetic dianhydride (EDTAD)-modified magnetic-Fe3O4 chitosan (EMC), prepared using the cross-link agent glutaraldehyde and chemicals Fe3O4, chitosan, and EDTAD, was used to compare the adsorption of methylene blue (MB) with magnetic chitosan (MC). The composite structure was confirmed by multiple characterization techniques, including scanning electron microscopy (SEM), X-ray powder diffraction, Fourier transform infrared spectroscopy (FTIR), and potentiometric titration methods. The characterization results suggest that Fe3O4 particles successfully bound on the surface of chitosan, and the EDTAD thoroughly modified the MC. Furthermore, EMC had more amino, carboxyl, and hydroxy groups than typical MC. Adsorption conditions, such as pH values, initial concentrations of MB, reaction temperature, and contact time were systematically examined. In comparison, the maximum adsorption capacity of EMC was approximately twice as much as that of MC. The recovery efficiency for EMC was >80% using 0.1 M HCl as an eluent solution. Therefore, the results reported herein indicate that EMC is very attractive and imply a practical application for dye wastewater treatment.

Immobilization of Rhizopus oryzae lipase on magnetic Fe3O4-chitosan beads and its potential in phenolic acids ester synthesis

A novel and simple method was developed for the preparation of magnetic Fe3O4 nanoparticles by chemical co-precipitation method and subsequent coating with 3-aminopropyltrimethoxysilane (APTMS) through silanization process. Magnetic Fe3O4-chitosan particles were prepared by the suspension cross-linking and covalent technique to be used in the application of magnetic carrier technology. The synthesized immobilization supports were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). Using glutaraldehyde as the coupling agent, the lipase from R. oryzae was successfully immobilized onto the functionalized magnetic Fe3O4-chitosan beads. The results showed that 86.60% of R. oryzae lipase was bound on the synthesized immobilization support. This immobilized lipase was successfully used for the esterification of phenolic acid which resulted in esterification of phenolic acid in isooctane solvent reaction system for 8 consecutive cycles (totally 384 h), 72.6% of its initial activity was retained, indicating a high stability in pharmaceutical and industrial applications.