Fe3O4 Chitosan Research Articles

A Comparative Study on the Biopolymer Functionalized Iron Oxide Nanocomposite for Antimicrobial Activity

Compared with bulk materials, nanoparticles have many outstanding properties, like optical, electronic, catalytic, and magnetic properties. Here the magnetite (Fe3O4) nanoparticles and biopolymer functionalized magnetite nanoparticles were synthesized by simple co-precipitation by using an aqueous solution containing ferrous (Fe2+) and ferric (Fe3+) ion salts in an alkaline media with poly (ethylene glycol) (PEG 400) as the surfactant. Both bare and Chitosan-coated iron oxide nanoparticles (IONPs) were subsequently characterized and evaluated for their antibacterial activity against Escherichia coli KL226. The XRD result indicates the formation of Fe3O4 nanoparticles and Chitosan (CS) coated Fe3O4 nanoparticles. Fourier transform infrared spectroscopy (FT-IR) studies confirm the bonding of the Chitosan polymer with Fe3O4 nanoparticles. The magnetic properties of the samples were measured by vibration sample magnetometer that confirmed ferromagnetic behaviour of magnetite nanoparticles at room temperature. The antibacterial test showed inhibition against E. coli with significant antagonistic activity.

Controlled release of protein from magnetite–chitosan nanoparticles exposed to an alternating magnetic field

ABSTRACTIn this research, the controlled release of proteins from magnetite (Fe3O4)–chitosan (CS) nanoparticles exposed to an alternating magnetic field is reported. Fe3O4–CS nanoparticles were synthesized with sodium tripolyphosphate (TPP) molecules as a crosslinking reagent. Bovine serum albumin (BSA) was used as a model protein, and its controlled release studied through the variation of the frequency of an alternating magnetic field. The results show the successful coating of CS and BSA on the Fe3O4 nanoparticles with an average diameter of 50 nm. Intermolecular interactions of TPP with CS and BSA were confirmed by Fourier transform infrared spectroscopy. The application of low‐frequency alternating magnetic fields to such magnetic CS nanoparticles enhanced the protein release properties, in which the external magnetic fields could switch on the unloading of these nanoparticles. We concluded that enhanced BSA release from nanoparticles exposed to an alternating magnetic field is a promising method for achieving both the targeted delivery and controlled release of proteins. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43335.

Efficient oxidation of sulfides into sulfoxides catalyzed by a chitosan–Schiff base complex of Cu(II) supported on supramagnetic Fe3O4 nanoparticles

Sulfoxides are versatile synthetic intermediates for the preparation of biological products. Therefore, there is a need for efficient methods to oxidize sulfides into sulfoxides. Such oxidation may be catalyzed by magnetic nanocatalysts due to their good stability, easy synthesis, high surface area, low toxicity and easy separation by magnetic forces. Here we prepared a nanocatalyst by immobilization of the chitosan–Schiff base complex on supramagnetic Fe3O4 nanoparticles. The chitosan–Schiff base complex has been previously prepared by functionalization of chitosan with 5-bromosalicylaldehyde and metalation with copper(II) acetate. The catalyst was characterized by Fourier transform infrared, powder X-ray diffraction, transmission electron microscope, scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermogravimetric analysis. Results show that the Fe3O4 nanoparticles and nanocatalyst were spherical in shape with an average size of 20 nm. Upon the covalently anchoring of chitosan–Schiff base Cu complex on the magnetic Fe3O4 nanoparticles, the average size increased to 60 nm. The prepared Fe3O4–chitosan–Schiff base Cu complex catalyzed very efficiently the oxidation of sulfides to sulfoxides with 100 % selectivity in all cases under green reaction conditions and excellent yields. Additionally, ease of recovery and reusability up to four cycles without noticeable loss of catalytic activity make the present protocol beneficial from industrial and environmental viewpoint.

A novel glucose sensor based on immobilization of glucose oxidase on the chitosan-coated Fe3O4 nanoparticles and the luminol–H2O2–gold nanoparticle chemiluminescence detection system

A novel and efficient glucose biosensor based on the chemiluminescence (CL) detection of enzymatically generated H2O2 was constructed by the effective immobilization of glucose oxidase (GOX) on the Fe3O4–chitosan (Fe3O4–CS) nanoparticles support. The covalent immobilization of enzyme was performed using glutheraldehyde (GA) as a cross-linking agent. (H2O2 was constructed by one covalent immobilization of glucose oxidase in glutaraldehyde-functionalized glass cell). In addition to catalyzes the luminol CL reaction, gold NPs offer excellent catalytic activity toward hydrogen peroxide generation as a result of enzymatic reaction between glucose oxidase and glucose. Based on response surface methodology (RSM), the optimal immobilization conditions for glucose oxidase were obtained as: enzyme to support ratio, 0.7; Immobilization pH, 6; cross-linking time, 75min; and glutaraldehyde (GA) concentration, 0.2%. The characterization of Fe3O4, Fe3O4–chitosan and Au nanoparticles was analyzed by XRD, FT-IR and SEM. The linear range of this novel method is 1×10−4 to 8.5×10−7molL−1 (R2=0.9956). The detection limit is 4.3×10−7molL−1. The relative standard deviation (RSD) <3.1% was obtained.

Construction of enzyme immobilization system through metal-polyphenol assisted Fe3O4/chitosan hybrid microcapsules

Metal-polyphenol film consolidated Fe3O4/chitosan hybrid microcapsules (MPP–Fe3O4/CS) were developed based on Fe3O4/chitosan (Fe3O4/CS) aggregation and tannic acid–FeIII (TA–FeIII) coating. Specifically, citrate modified Fe3O4 nanoparticles were adsorbed onto enzyme-encapsulated chitosan–citrate (CS–citrate) microaggregates via ion exchange. After continuous stirring, the citrate moieties in the internal part of CS–citrate microaggregates were released to the bulk solutions and caused the disassembly of CS–citrate microaggregates, thus generating the enzyme-encapsulated capsule lumen. To further obtain an intact and robust structure, metal-polyphenol (TA–FeIII) was utilized to form adhesive coatings on the surface of Fe3O4/CS microcapsules. The microcapsule preparation process can be completed within 40min. The candida rugosa lipase (CRL), was used as the target enzyme to be encapsulated in the microcapsules. After studying the properties of immobilized CRL such as activity, kinetic behaviors, stability and reusability, it was proved that TA–FeIII consolidated Fe3O4/CS microcapsules exhibited more excellent properties than Fe3O4/CS microcapsules only. Moreover, the magnetic microcapsules can be easily recycled by an extra magnetic field for the next use due to the high saturation magnetization values. The convenient operation process kept the enzyme activity as high as 70% and 77.8% for Fe3O4/CS and MPP–Fe3O4/CS after 12 times reuse respectively. Hopefully, the feasible, rapid and low cost assembly process may ensure the wide application in bio-catalysis of the hybrid microcapsules.

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.

Development of a novel magnetite–chitosan composite for the removal of fluoride from drinking water: adsorption modeling and optimization

Fe3O4–chitosan can be separated both quickly and easily. The magnetization of adsorbents and use of magnetic separation techniques can be an effective way to resolve problems associated with separation and filtration.

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.

Facile self-assembly of magnetite nanoparticles on three-dimensional graphene oxide–chitosan composite for lipase immobilization

Three dimensional (3D) magnetic graphene oxide–chitosan (GO–CS) composites with orderly self-assembled magnetite (Fe3O4) nanoparticles (GO–CS–Fe3O4) were successfully fabricated. First, the covalent functionalization of graphene oxide (GO) using chitosan (CS) was successfully accomplished via a facile amidation process, forming a 3D network. In the as-fabricated GO–CS composites, GO sheets remained less aggregated, exhibiting a large surface area, and the interconnected pores in the hydrogels allowed object molecules to diffuse easily into the composites. Subsequently, the GO–CS–Fe3O4 composites were synthesized using FeCl3·6H2O and GO–CS composite as the starting materials through a solvothermal reaction. The resulting composite combined the features of the high surface area of GO, abundant amino, and hydroxyl functional groups of CS, and the magnetic response of magnetic nanoparticles. For further application, these composites were utilized to immobilize Candida rugosa lipase via different routes, and they showed excellent immobilization capacities.

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.

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.

Synthesis and characterization of magnetically separable Ag nanoparticles decorated mesoporous Fe3O4@carbon with antibacterial and catalytic properties

Mesoporous composite particles of carbon inlaid with Fe3O4 nanoparticles (designated as Fe3O4@carbon) with a novel bowl structure and magnetic separation property were fabricated by a spray drying assisted template method using chitosan as carbon precursor and silica nanoparticles as pore directing agent. The influence of the contents among Fe3O4 nanoparticles, chitosan and silica nanoparticle on the formation of porous Fe3O4@carbon composite particles has been discussed. Ag nanoparticles were then deposited onto the surface of mesoporous Fe3O4@carbon substrates using silver acetate as precursor with the assistance of ultrasound treatment. The matrices of Ag nanoparticles decorated Fe3O4@carbon composite particles (denoted as Ag–(Fe3O4@carbon)) were derived and characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) spectroscopy, nitrogen adsorption–desorption, and magnetic property measurements. The Ag–(Fe3O4@carbon) composites showed efficient antibacterial activities to Escherichia coli and Staphylococcus aureus, high catalytic activity to the reduction of 4-nitrophenol (4-NP) in the presence of NaBH4, strong adsorption ability to organic molecules, and efficient separability under a magnetic field.

Construction of an Amperometric Glucose Biosensor by Immobilization of Glucose Oxidase on Nanocomposite at the Surface of FTO Electrode

AbstractFluorinetin oxide (FTO) nanostructure was developed on the surface of a glass plate using spray payroliziz method. A new electrochemical biosensor was fabricated based on a layer by layer process. In this process chitosanFe3O4 (CHFe3O4) nanocomposite film was prepared at the surface of FTO electrode by dipcoating method. In the next step, the glucose oxidase (GOx) was immobilized on the CHFe3O4/FTO nanocomposite electrode. The GOx/CHFe3O4/FTO bioelectrode has a linear range of 10–270 µM and a detection limit of 5 µM. The highest sensitivity was obtained at 1.2 µA mM−1 cm−2.

Superparamagnetic iron oxide/chitosan core/shells for hyperthermia application: Improved colloidal stability and biocompatibility

Superparamagnetic magnetite nanoparticles are of great interest due to their potential biomedical applications. In the present investigation, Fe3O4 magnetic nanoparticles were prepared by alkaline precipitation using ferrous chloride as the sole source. An amphiphilic polyelectrolyte with the property of biocompatibility and functional carboxyl groups was used as a stabilizer to prepare a well-dispersed suspension of superparamagnetic Fe3O4 nanoparticles. The final material composed of Fe3O4 core and chitosan (CH) shell was produced. The amino groups of CH coated on Fe3O4 nanoparticles were further cross linked using glutaraldehyde (GLD) for stable coating. FTIR spectra, XPS and TGA confirmed the coating of CH/GLD on the surface of Fe3O4 nanoparticles. XRD patterns indicate the pure phase Fe3O4 with a spinel structure. The nanoparticles were superparamagnetic at room temperature with saturation magnetization values for bare and coated nanoparticles which were 51.68emu/g and 48.60emu/g, respectively. Zeta potential values showed higher colloidal stability of coated nanoparticles than the bare one. Cytotoxicity study up to 2mgmL−1 concentration showed no drastic change in cell viability of nanoparticles after coating. Also, coated nanoparticles showed increased SAR value, making them suitable for hyperthermia therapy application.

Electrochemistry and electrocatalysis of myoglobin on carbon coated Fe3O4 nanospindle modified carbon ionic liquid electrode

In this paper, carbon coated Fe3O4 nanospindles (C@Fe3O4 NSs) were synthesized by partial reduction of monodispersed hematite nanospindles with carbon coatings and applied to investigate the direct electrochemistry of myoglobin (Mb). A novel modified electrode was prepared by applying carbon coated Fe3O4 nanospindles, Mb, ionic liquid (IL), 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM]EtOSO3) and chitosan (CTS) step by step onto the surface of a carbon ionic liquid electrode (CILE) with another ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4), as the binder. UV-Vis absorption and FT-IR spectra results indicated that Mb retained its native structure in the composite film. The electrochemical behavior of the CTS/IL/Mb/C@Fe3O4/CILE was investigated and a pair of well-defined redox peaks appeared, which indicated that the direct electron transfer of Mb was realized with the underlying electrode. The fabricated CTS/IL/Mb/C@Fe3O4/CILE showed good electrocatalytic activity in the reduction of trichloroacetic acid (TCA) with a linear range from 1.0 to 20.0 mM, which showed potential applications for fabricating novel electrochemical biosensors and bioelectronic devices.

Reduction of Fe(III)EDTA− in a NOx scrubbing solution by magnetic Fe3O4–chitosan microspheres immobilized mixed culture of iron-reducing bacteria

Magnetic Fe3O4–chitosan microspheres were prepared by co-precipitating of Fe2+ and Fe3+ ions with NaOH in the presence of chitosan. The saturated magnetization of the resulting material was 20.0emu/g. Then these magnetic microspheres were employed to immobilize iron-reducing bacteria to improve the biological reduction of Fe(III)EDTA−, which was one of the key steps in nitrogen oxides (NOx) removal by the integrated chemical absorption–biological reduction process. The immobilized bacteria performed well on Fe(III)EDTA− reduction than free bacteria, even under unfavorable pH and temperatures. Furthermore, the effects of NO2-,NO3-,SO3-, and S2−, the potential inhibition compounds in the scrubber solution, on the reduction of Fe(III)EDTA− by the immobilized and free bacteria were also studied.

Application of chitosan/Fe3O4 microsphere–graphene composite modified carbon ionic liquid electrode for the electrochemical detection of the PCR product of soybean Lectin gene sequence

In this paper a Fe3O4 microsphere, graphene (GR) and chitosan (CTS) nanocomposite material modified carbon ionic liquid electrode (CILE) was used as the platform for the construction of a new electrochemical DNA biosensor. The single-stranded DNA (ssDNA) probe was immobilized directly on the surface of the CTS/Fe3O4–GR/CILE, which could hybridize with the target ssDNA sequence at the selected conditions. By using methylene blue (MB) as the electrochemical indicator the hybridization reaction was investigated with the reduction peak current measured. By combining the specific properties such as the biocompatibility and big surface area of Fe3O4 microspheres, the excellent electron transfer ability of GR, the good film-forming ability of CTS and the high conductivity of CILE, the synergistic effects of nanocomposite increased the amounts of ssDNA adsorbed on the electrode surface and then resulted in the greatly increase of the electrochemical responses. Under the optimal conditions differential pulse voltammetric responses of MB were proportional to the specific ssDNA sequences concentration in the range from 1.0×10−12 to 1.0×10−6mol/L with the detection limit as 3.59×10−13mol/L (3σ). This DNA biosensor showed good stability and discrimination ability to one-base and three-base mismatched ssDNA sequences. The polymerase chain reaction (PCR) product of soybean Lectin gene sequence was detected by the proposed method with satisfactory result, suggesting that the CTS/Fe3O4–GR/CILE was a suitable sensing platform for the sensitive detection of specific gene sequence.

Modulating cell-uptake behavior of Au-based nanomaterials via quantitative biomolecule modification

The pre-modification method provides a rapid and controllable amount of biomolecule conjugated to nanomaterials via quantitative creation of “activated sites” on biomolecules, modulating specific targeting rate toward cancer cells. In our studies, activating reagent, 2-iminothiolane, is introduced into the biomolecule structure as activated site for linking to Au nanomaterial. To fabricate Au-based magnetic nanoparticles, the amounts of Au nanoparticles are controllably conjugated to chitosan–Fe3O4 nanoparticles by increasing activated sites on chitosan, adjusted by 2-iminothiolane concentration. Further, to develop the biorecognition of Au–Fe3O4 nanoparticles toward target cells, pre-modified transferrin (Tf) is allowed to facilitate the conjugation with Au–Fe3O4 nanoparticles, and validations of bioactivity and specificity are examined in vitro using J5 cancer cells as well. The cell uptake analysis indicates that the high-degree Tf modified Au–Fe3O4 nanoparticles have rapid-targeting ability and easy internalization toward cancer cell, compared to low-degree ones. It implies that the efficiency of cell targeting can be improved or lowered by modulating Tf modification. The potential control of applications can be achieved by modulating Tf modification, such as rapid-targeting rate for signal enhancement, the long-term or rapid drug-treatment in circulation, etc. This concept of modulating by Tf modification can be extensively utilized in future designs of various biomolecule-conjugated Au-based nanomaterials.

Novel and efficient method for immobilization and stabilization of β-d-galactosidase by covalent attachment onto magnetic Fe3O4–chitosan nanoparticles

A novel and efficient immobilization of β-d-galactosidase from Aspergillus oryzae has been developed by using magnetic Fe3O4–chitosan (Fe3O4–CS) nanoparticles as support. The magnetic Fe3O4–CS nanoparticles were prepared by electrostatic adsorption of chitosan onto the surface of Fe3O4 nanoparticles made through co-precipitation of Fe2+ and Fe3+. The resultant material was characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometry and thermogravimetric analysis. β-d-Galactosidase was covalently immobilized onto the nanocomposites using glutaraldehyde as activating agent. The immobilization process was optimized by examining immobilized time, cross-linking time, enzyme concentration, glutaraldehyde concentration, the initial pH values of glutaraldehyde and the enzyme solution. As a result, the immobilized enzyme presented a higher storage, pH and thermal stability than the soluble enzyme. Galactooligosaccharide was formed with lactose as substrate by using the immobilized enzyme as biocatalyst, and a maximum yield of 15.5% (w/v) was achieved when about 50% lactose was hydrolyzed. Hence, the magnetic Fe3O4–chitosan nanoparticles are proved to be an effective support for the immobilization of β-d-galactosidase.

Direct electrochemistry and electrocatalysis of hemoglobin immobilized in a magnetic nanoparticles-chitosan film

Magnetic nanoparticles (Fe3O4) were synthesized by a chemical coprecipitation method. X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to confirm the crystallite structure and the particle's radius. The Fe3O4 nanoparticles and chitosan (CS) were mixed to form a matrix in which haemoglobin (Hb) can be immobilized for the fabrication of H2O2 biosensor. The Fe3O4–CS–Hb film exhibited a pair of well-defined and quasi-reversible cyclic voltammetric peaks due to the redox of Hb–heme Fe (III)/Fe (II) in a pH 7.0 phosphate buffer. The formal potential of Hb–heme Fe(III)/Fe(II) couple varied linearly with the increase of pH in the range of 4.0–10.0 with a slope of 46.5mVpH−1, indicating that electron transfer was accompanied with single proton transportation in the electrochemical reaction. The surface coverage of Hb immobilized on Fe3O4–CS film glassy carbon electrode was about 1.13×10−10molcm−2. The heterogeneous electron transfer rate constant (ks) was 1.04s−1, indicating great facilitation of the electron transfer between Hb and magnetic nanoparticles-chitosan modified electrode. The modified electrode showed excellent electrocatalytic activity toward oxygen and hydrogen peroxide reduction. The apparent Michaelis–Menten constant KMapp for H2O2 was estimated to be 38.1μmolL−1.