Coprecipitation Of Iron Salts Research Articles

Heparin-Superparamagnetic Iron Oxide Nanoparticles for Theranostic Applications.

In this study, superparamagnetic iron oxide nanoparticles (SPIONs) were engineered with an organic coating composed of low molecular weight heparin (LMWH) and bovine serum albumin (BSA), providing heparin-based nanoparticle systems (LMWH@SPIONs). The purpose was to merge the properties of the heparin skeleton and an inorganic core to build up a targeted theranostic nanosystem, which was eventually enhanced by loading a chemotherapeutic agent. Iron oxide cores were prepared via the co-precipitation of iron salts in an alkaline environment and oleic acid (OA) capping. Dopamine (DA) was covalently linked to BSA and LMWH by amide linkages via carbodiimide coupling. The following ligand exchange reaction between the DA-BSA/DA-LMWH and OA was conducted in a biphasic system composed of water and hexane, affording LMWH@SPIONs stabilized in water by polystyrene sulfonate (PSS). Their size and morphology were investigated via dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The LMWH@SPIONs’ cytotoxicity was tested, showing marginal or no toxicity for samples prepared with PSS at concentrations of 50 µg/mL. Their inhibitory activity on the heparanase enzyme was measured, showing an effective inhibition at concentrations comparable to G4000 (N-desulfo-N-acetyl heparin, a non-anticoagulant and antiheparanase heparin derivative; Roneparstat). The LMWH@SPION encapsulation of paclitaxel (PTX) enhanced the antitumor effect of this chemotherapeutic on breast cancer cells, likely due to an improved internalization of the nanoformulated drug with respect to the free molecule. Lastly, time-domain NMR (TD-NMR) experiments were conducted on LMWH@SPIONs obtaining relaxivity values within the same order of magnitude as currently used commercial contrast agents.

Magneto-Mechanically Triggered Thick Films for Drug Delivery Micropumps.

Given the demanding use of controlled drug delivery systems, our attention was focused on developing a magnetic film that can be triggered in the presence of a magnetic field for both drug delivery and the actuating mechanism in micropump biomedical microelectromechanical systems (BioMEMS). Magnetic alginate films were fabricated in three steps: the co-precipitation of iron salts in an alkaline environment to obtain magnetite nanoparticles (Fe3O4), the mixing of the obtained nanoparticles with a sodium alginate solution containing glycerol as a plasticizer and folic acid as an active substance, and finally the casting of the final solution in a Petri dish followed by cross-linking with calcium chloride solution. Magnetite nanoparticles were incorporated in the alginate matrix because of the well-established biocompatibility of both materials, a property that would make the film convenient for implantable BioMEMS devices. The obtained film was analyzed in terms of its magnetic, structural, and morphological properties. To demonstrate the hypothesis that the magnetic field can be used to trigger drug release from the films, we studied the release profile in an aqueous medium (pH = 8) using a NdFeB magnet as a triggering factor.

Effect of an oscillating magnetic field in polymeric columns with magnetic nanoparticles

Magnetite magnetic nanoparticles (MNP) exhibit superparamagnetic behavior, which gives them important properties such as low coercive field, easy superficial modification and acceptable magnetization levels. This makes them useful in separation techniques. However, few studies have experimented with the interactions of MNP with magnetic fields. Therefore, the aim of this research was to study the influence of an oscillating magnetic field (OMF) on polymeric monolithic columns with vinylated magnetic nanoparticles (VMNP) for capillary liquid chromatography (cLC). For this purpose, MNP were synthesized by coprecipitation of iron salts. The preparation of polymeric monolithic columns was performed by copolymerization and aggregation of VMNP. Taking advantage of the magnetic properties of MNP, the influence of parameters such as resonance frequency, intensity and exposure time of a OMF applied to the synthesized columns was studied. As a result, a better separation of a sample according to the measured parameters was obtained, so that a column resolution (Rs) of 1.35 was achieved. The morphological properties of the columns were evaluated by scanning electron microscopy (SEM). The results of the chromatographic properties revealed that the best separation of the alkylbenzenes sample occurs under conditions of 5.5 kHz and 10 min of exposure in the OMF. This study constitutes a first application in chromatographic separation techniques for future research in nanotechnology.

Synthesis and characterization of magnetic iron oxide – silica nanocomposites used for adsorptive recovery of palladium (II)

ABSTRACT Magnetic iron oxide-silica shell nanocomposites (IONP@SiO2) have been prepared in a two-step procedure. IONPs were obtained by coprecipitation of iron salts, and coated by silica in sol-gel method under sonication. Two IONP/silica ratios and two drying methods, heating in oven and supercritical CO2 drying, were used. The samples were analyzed using X-ray diffraction (XRD), infrared spectroscopy, magnetic measurements, small-angle neutron scattering (SANS), nitrogen sorption, and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray analysis (EDX). The iron oxide silica nanocomposites obtained via supercritical drying exhibited higher values of the specific surface area and of saturation magnetization compared to the samples synthesized with the same iron oxide content but obtained after drying at 60 °C. Pd(II) adsorption experiments were performed on the materials prepared by supercritical drying. The maximum adsorption capacity 6.5 mg/g showed that the materials can be used as good and cheap adsorbent for palladium ions from aquatic environment.

INVESTIGATION ON THE PHYSICO - CHEMICAL PROPERTIES OF MAGNETIC CLAY COMPOSITES

This article studies the main physical and chemical properties of magnetic clays. Structural changes in magnetic clay composite suspensions were evaluated by measuring the permittivity through direct measurement of the sensor capacitance and through computer measurement of the frequency of the electric signal inversely proportional to the sensor capacitance. Natural bentonite clay of the Tagan field (East Kazakhstan region) was used in this study. Magnetite synthesized by the method of co-precipitation of iron salts with magnetite-clay composites. Different compositions of clay-magnetite compounds were investigated to study the magnetic properties of the samples. According to the study, with the increasing of magnetite in the composition the magnetic properties increase. However, increasing the magnetite in the composition leads to lose the stability of the suspension. The stability of the suspension also investigated by measuring of the size of the particles. Depending on the findings of the study 20% magnetite-clay composition was the optimal value for the magnetic solution.

A rapid antimicrobial photodynamic water treatment strategy utilizing a xanthene dye with subsequent removal by Goethite Nanoparticles

Although widely accepted as a water sterilisation technique, chlorination results in the production of potentially harmful by-products, mainly Trihalomethanes. Furthermore, the chlorination process requires specialised infrastructure, management and high costs. In this research paper a potential alternative sterilisation technique was investigated. This rapid three-step process utilized Goethite Nanoparticles and the photosensitising capabilities of a xanthene dye. Rose Bengal (RB) a compound primarily used as a stain to diagnose damaged tissue in the eye was utilized under visible light excitation to sterilise water containing gram-positive Staphylococcus aureus and Bacillus cereus. Bacterial reductions (cfu/ml) of up to 6log10 are reported at RB concentrations of 0.5 mg/L and 10 mg/L for S. aureus and B. cereus, respectively. Goethite Nanoparticles (GNP's), an iron oxyhydroxide, were synthesised by co-precipitation of iron salts and used to adsorb RB post-sterilisation. Poly-vinyl Alcohol (PVA) functionalised GNP's were synthesised to highlight the adsorbent capabilities of the GNP surface. The adsorption capacity for uncoated GNPs was 476.19 mg/g, this reduced to 170.4 mg/g for PVA-GNP's, highlighting the highly porous nature of the synthesised GNP surface. Adsorption was optimal in slightly acidic conditions (pH5-6). The adsorption parameters best followed Lagergens Pseudo-second order kinetics with correlation coefficients close to unity. At the highest envisaged RB concentration (10 mg/L) approximately 20 mg/L GNP's was required to remove the dye from solution post-treatment. Flame Atomic Absorption analysis of the water post-removal revealed Iron concentrations of 0.058 mg/L. This correlates to removal efficacy of 99.71% with residual iron levels below the EU recommended limit of 0.2 mg/L.

Trihydrazinotriazine-grafting Fe3O4/SiO2 core-shell nanoparticles with expanded porous structure for organic reactions

This study focuses on the synthesis and characterization of a novel magnetic nanocomposite 2,4,6-trihydrazino-1,3,5-triazine (THDT)-functionalized with silica-coated iron oxide magnetic nanoparticles (MNPs). This nanocomposite has porous morphology decorated with the spherical MNPs. Through co-precipitation of iron salts, MNPs were obtained. The prepared THDT was placed on the chlorine surface-modified MNPs. The present environment-friendly nanocatalyst intensely accelerated the synthesis of highly functionalized tetrahydrobenzo[b]pyran derivatives as well as reduced the reaction times and increased yields of the products.

Influencia de un campo magnético oscilante en columnas poliméricas con nanopartículas magnéticas (ARTÍCULO RETRACTADO)

ARTÍCULO RETRACTADO Las nanopartículas magnéticas de magnetita (MNP) presentan comportamiento superparamagnético, lo que les confiere propiedades importantes como bajo campo coercitivo, fácil modificación superficial y niveles de magnetización aceptables. Esto las hace útiles en técnicas de separación. Sin embargo, pocos estudios han experimentado con las interacciones de las MNP con campos magnéticos. Por tanto, el objetivo de esta investigación fue estudiar la influencia de un campo magnético oscilante (CMO) en columnas monolíticas poliméricas con nanopartículas magnéticas vinilizadas (VMNP) para cromatografía líquida capilar (cLC). Para ello, se sintetizaron MNP mediante coprecipitación de sales de hierro. La preparación de las columnas monolíticas poliméricas se realizó por copolimerización y la agregación de VMNP. Aprovechando las propiedades magnéticas de las MNP, se estudió la influencia de los parámetros como frecuencia de resonancia, intensidad y tiempo de exposición de un CMO, aplicado a las columnas sintetizadas. Como resultado se obtuvo una mejor separación de una muestra según los parámetros medidos, de modo que se logró una resolución de la columna (Rs) de 1,35. Las propiedades morfológicas de las columnas fueron evaluadas mediante microscopía electrónica de barrido (SEM). Los resultados de las propiedades cromatográficas revelaron que la mejor separación de la muestra de alquilbencenos se da en condiciones de 5,5 kHz y 10 min de exposición en el CMO. Este estudio constituye una primera aplicación en técnicas de separación cromatográficas para futuras investigaciones en nanotecnología.

Controlled Synthesis of Magnetic Iron Oxide Nanoparticles: Magnetite or Maghemite?

Today, magnetic nanoparticles are present in multiple medical and industrial applications. We take a closer look at the synthesis of magnetic iron oxide nanoparticles through the co-precipitation of iron salts in an alkaline environment. The variation of the synthesis parameters (ion concentration, temperature, stirring rate, reaction time and dosing rate) change the structure and diameter of the nanoparticles. Magnetic iron oxide nanoparticles are characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). Magnetic nanoparticles ranging from 5 to 16 nm in diameter were synthesized and their chemical structure was identified. Due to the evaluation of Raman spectra, TEM and XRD, the magnetite and maghemite nanoparticles can be observed and the proportion of phases and the particle size can be related to the synthesis conditions. We want to highlight the use of Raman active modes A1g of spinel structured iron oxides to determine the content of magnetite and maghemite in our samples. Magnetite nanoparticles can be derived from highly alkaline conditions even without establishing an inert atmosphere during the synthesis. The correlation between the particle properties and the various parameters of the synthesis was modelled with linear mixture models. The two models can predict the particle size and the oxidation state of the synthesized nanoparticles, respectively. The modeling of synthesis parameters not only helps to improve synthesis conditions for iron oxide nanoparticles but to understand crystallization of nanomaterials.

Biocompatible superparamagnetic nanoparticles with ibuprofen as potential drug carriers

This article describes the synthesis, characterization, in vitro cytotoxic and genotoxicity evaluation of chitosan-iron oxide nanoparticles (Fe3O4-CS) as vehicles for ibuprofen (IBU) molecule. Magnetite (Fe3O4) nanoparticles were synthesized by co-precipitation of iron salts and coated with chitosan, leading to the formation of Fe3O4-CS hybrid nanoparticles, and then IBU was adsorbed on the surface of the modified nanoparticles. The physicochemical, morphological, and magnetic properties of the nanoparticles were determined by X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and SQUID magnetic measurements. The nanoparticles have shown stability in aqueous medium presenting an average hydrodynamic size of 36 ± 9 nm for Fe3O4-CS, and 132 ± 1 nm for Fe3O4-CS-IBU. The cytotoxicity of nanoparticles using the cell viability of the blood mononuclear cell fraction and the analysis of gene expression of the repair genes hMSH2, hMSH6 and NF-kB were performed to evaluate their applicability as drug carriers. The results showed that Fe3O4-CS nanoparticles are suitable candidates as magnetic vehicles for ibuprofen in biomedical applications.

Hyperbranched Polymer-Functionalized Magnetic Nanoparticle-Mediated Hyperthermia and Niclosamide Bimodal Therapy of Colorectal Cancer Cells.

Functionalized magnetic nanoparticles (MNPs) have attracted particular interest as potential drug delivery carriers as they offer dual advantage of delivering drugs to the target site complemented with magnetic hyperthermia-mediated therapy. Hyperbranched polymer-functionalized MNPs have the potential to perform a dual role of killing cancer cells by hyperthermia (by magnetite core) with apoptosis (by loaded niclosamide). These are formed by the co-precipitation of iron salts followed by aminocellulose grafting, branch growth, and PEGylation. NP formation was investigated by determining particle size, zeta potential, and microscopic (transmission electron microscopy, field-emission scanning electron microscopy, and atomic force microscopy) studies. Results showed that these nanocarriers were 107 ± 57 nm in size with a zeta potential of -18 mV and exist as NPs. Drug loading and encapsulation efficiency were calculated as 15.28 ± 2.72 and 76.41 ± 1.84%, respectively, using UV-vis spectroscopy. NPs were internalized into HCT116 cells as investigated using confocal microscopy and flow cytometry. Blank NPs at the dose of 200 μg/mL were found to be cytocompatible using hTERT cells and hemocompatible. The cell viability study suggested that niclosamide-loaded functionalized magnetic nanoparticles (NFMNPs) were more effective (7 times) than free niclosamide in killing colon cancer cells. Moreover, NFMNPs induced apoptosis in an immunofluorescence study of cleaved caspase-3. Exposure of NFMNPs to an alternating magnetic field (AMF) resulted in a slight increase in the rate of niclosamide release. AMF exposure drastically reduced cell viability due to dual effects of hyperthermia and niclosamide after treatment with NFMNPs. The potentiation of cell death due to dual effects of hyperthermia and niclosamide was further confirmed by Annexin-V/propidium iodide assay using flow cytometry. The results imply that niclosamide delivery through hyperbranched polymer-functionalized MNPs may serve as an effective strategy for the treatment of colorectal cancer.

In vivo evaluation of thiol-functionalized superparamagnetic iron oxide nanoparticles

This article describes the synthesis, characterization and in vivo cytotoxic evaluation of thiol-functionalized superparamagnetic iron oxide magnetic nanoparticles (SPIONs). They have been employed as potential vehicles for a large number of biomedical applications, such as drug delivery. Fe3O4 nanoparticles were synthesized by coprecipitation of iron salts and coated with L-cysteine. The physicochemical, morphological, and magnetic properties of Cys-Fe3O4 nanoparticles were characterized by different experimental techniques. To evaluate their applicability in nanomedicine we evaluated their cytotoxicity using Balb/C mice. The results show that Cys-SPIONs are good candidates as nanocarriers in biomedical applications.

Functionalized porous silica&maghemite core-shell nanoparticles for applications in medicine: design, synthesis, and immunotoxicity.

AimTo determine cytotoxicity and effect of silica-coated magnetic nanoparticles (MNPs) on immune response, in particular lymphocyte proliferative activity, phagocytic activity, and leukocyte respiratory burst and in vitro production of interleukin-6 (IL-6) and 8 (IL-8), interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and granulocyte macrophage colony stimulating factor (GM-CSF).MethodsMaghemite was prepared by coprecipitation of iron salts with ammonia, oxidation with NaOCl and modified by tetramethyl orthosilicate and aminosilanes. Particles were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). Cytotoxicity and lymphocyte proliferative activity were assessed using [3H]-thymidine incorporation into DNA of proliferating human peripheral blood cells. Phagocytic activity and leukocyte respiratory burst were measured by flow cytometry; cytokine levels in cell supernatants were determined by ELISA.Resultsγ-Fe2O3&SiO2-NH2 MNPs were 13 nm in size. According to TEM, they were localized in the cell cytoplasm and extracellular space. Neither cytotoxic effect nor significant differences in T-lymphocyte and T-dependent B-cell proliferative response were found at particle concentrations 0.12-75 μg/cm2 after 24, 48, and 72 h incubation. Significantly increased production of IL-6 and 8, and GM-CSF cytokines was observed in the cells treated with 3, 15, and 75 µg of particles/cm2 for 48 h and stimulated with pokeweed mitogen (PHA). No significant changes in TNF-α and IFN-γ production were observed. MNPs did not affect phagocytic activity of monocytes and granulocytes when added to cells for 24 and 48 h. Phagocytic respiratory burst was significantly enhanced in the cultures exposed to 75 µg MNPs/cm2 for 48 h.ConclusionsThe cytotoxicity and in vitro immunotoxicity were found to be minimal in the newly developed porous core-shell γ-Fe2O3&SiO2-NH2 magnetic nanoparticles.

A novel synthesis of Fe2O3@activated carbon composite and its exploitation for the elimination of carcinogenic textile dye from an aqueous phase

The present work reports the synthesis of Fe2O3@activated carbon composites by the co-precipitation of iron salts onto activated carbon.

Controlled-release formulation of perindopril erbumine loaded PEG-coated magnetite nanoparticles for biomedical applications

Iron oxide nanoparticles (FNPs) were synthesized due to low toxicity and their ability to immobilize biological materials on their surfaces by the coprecipitation of iron salts in ammonia hydroxide followed by coating it with polyethylene glycol (PEG) to minimize the aggregation of iron oxide nanoparticles and enhance the effect of nanoparticles for biological applications. Then, the FNPs–PEG was loaded with perindopril erbumine (PE), an antihypertensive compound to form a new nanocomposite (FPEGPE). Transmission electron microscopy results showed that there are no significant differences between the sizes of FNPs and FPEGPE nanocomposite. The existence of PEG–PE was supported by the FTIR and TGA analyses. The PE loading (10.3 %) and the release profiles from FPEGPE nanocomposite were estimated using ultraviolet–visible spectroscopy which showed that up to 60.8 and 83.1 % of the adsorbed drug was released in 4223 and 1231 min at pH 7.4 and 4.8, respectively. However, the release of PE was completed very fast from a physical mixture (FNPs–PEG–PE) after 5 and 7 min at pH 4.8 and 7.4, respectively, which reveals that the release of PE from the physical mixture is not in the sustained-release manner. Cytotoxicity study showed that free PE presented slightly higher toxicity than the FNPs and FPEGPE nanocomposite. Therefore, the decrease toxicity against mouse normal fibroblast (3T3) cell lines prospective of this nanocomposite together with controlled-release behavior provided evidence of the possible beneficial biological activities of this new nanocomposite for nanopharmaceutical applications for both oral and non-oral routes.

Magnetic modification of microporous carbon for dye adsorption

In this study, impregnation of microporous activated carbon with magnetite was achieved by co-precipitation of iron salts onto activated carbon. The evaluation of the adsorption ability of this material was examined using the anionic dye Reactive Black 5 as model dye pollutant (adsorbate). The effect of pH, ionic strength, contact time and initial dye concentration were also studied. It was found that high pH and high ionic strength favor the adsorption of Reactive Black 5. The adsorption kinetics and isotherms were well fitted by the fractal BS model and Langmuir model, respectively. The impregnation with magnetite decreases the adsorption capacity of activated carbon. Thermal re-activation of dye-loaded activated carbons was also succeeded. The characterization of the magnetic carbons was investigated by various techniques (SEM/EDAX, VSM, BET, FTIR, XRD, DTG) revealing many possible interactions in the carbon-dye system.

Novel kojic acid-polymer-based magnetic nanocomposites for medical applications

Iron oxide magnetic nanoparticles (MNPs) were synthesized by the coprecipitation of iron salts in sodium hydroxide followed by coating separately with chitosan (CS) and polyethylene glycol (PEG) to form CS-MNPs and PEG-MNPs nanoparticles, respectively. They were then loaded with kojic acid (KA), a pharmacologically bioactive natural compound, to form KA-CS-MNPs and KA-PEG-MNPs nanocomposites, respectively. The MNPs and their nanocomposites were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, and scanning electron microscopy. The powder X-ray diffraction data suggest that all formulations consisted of highly crystalline, pure magnetite Fe3O4. The Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed the presence of both polymers and KA in the nanocomposites. Magnetization curves showed that both nanocomposites (KA-CS-MNPs and KA-PEG-MNPs) were superparamagnetic with saturation magnetizations of 8.1 emu/g and 26.4 emu/g, respectively. The KA drug loading was estimated using ultraviolet–visible spectroscopy, which gave a loading of 12.2% and 8.3% for the KA-CS-MNPs and KA-PEG-MNPs nanocomposites, respectively. The release profile of the KA from the nanocomposites followed a pseudo second-order kinetic model. The agar diffusion test was performed to evaluate the antimicrobial activity for both KA-CS-MNPs and KA-PEG-MNPs nanocomposites against a number of microorganisms using two Gram-positive (methicillin-resistant Staphylococcus aureus and Bacillus subtilis) and one Gram-negative (Salmonella enterica) species, and showed some antibacterial activity, which could be enhanced in future studies by optimizing drug loading. This study provided evidence for the promise for the further investigation of the possible beneficial biological activities of KA and both KA-CS-MNPs and KA-PEG-MNPs nanocomposites in nanopharmaceutical applications.

Magnetic Nanoclusters Exhibiting Protein-Activated Near-Infrared Fluorescence

Composite nanoclusters with chemical, magnetic, and biofunctionality offer broad opportunities for targeted cellular imaging. A key challenge is to load a high degree of targeting, imaging, and therapeutic functionality onto stable metal-oxide nanoparticles. Here we report a route for producing magnetic nanoclusters (MNCs) with alkyne surface functionality that can be utilized as multimodal imaging probes. We form MNCs composed of magnetic Fe(3)O(4) nanoparticles and poly(acrylic acid-co-propargyl acrylate) by the co-precipitation of iron salts in the presence of copolymer stabilizers. The MNCs were surface-modified with near-infrared (NIR) emitting fluorophore used in photodynamic therapy, an azide-modified indocyanine green. The fluorophores engaged and complexed with bovine serum albumin, forming an extended coverage of serum proteins on the MNCs. These proteins isolated indocyanine green fluorophores from the aqueous environment and induced an effective "turn-on" of NIR emission.

Structural, magnetic, and textural properties of iron oxide-reduced graphene oxide hybrids and their use for the electrochemical detection of chromium

Superparamagnetic Fe3O4 nanoparticles were anchored on reduced graphene oxide (RGO) nanosheets by co-precipitation of iron salts in the presence of different amounts of graphene oxide (GO). A pH dependent zeta potential and good aqueous dispersions were observed for the three hybrids of Fe3O4 and RGO. The structure, morphology and microstructure of the hybrids were examined by X-ray diffraction, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, Raman and X-ray photoelectron spectroscopy. TEM images reveal lattice fringes (d311=0.26nm) of Fe3O4 nanoparticles with clear stacked layers of RGO nanosheets. The textural properties including the pore size distribution and loading of Fe3O4 nanoparticles to form Fe3O4–RGO hybrids have been controlled by changing the concentration of GO. An observed maximum (∼10nm) in pore size distribution for the sample with 0.25mgml−1 of GO is different from that prepared using 1.0mgml−1 GO. The superparamagnetic behavior is also lost in the latter and it exhibits a ferrimagnetic nature. The electrochemical behavior of the hybrids towards chromium ion was assessed and a novel electrode system using cyclic voltammetry for the preparation of an electrochemical sensor platform is proposed. The textural properties seem to influence the electrochemical and magnetic behavior of the hybrids.

Synthesis, characterization and antibacterial activity of superparamagnetic nanoparticles modified with glycol chitosan

Iron oxide nanoparticles (IONPs) were synthesized by coprecipitation of iron salts in alkali media followed by coating with glycol chitosan (GC-coated IONPs). Both bare and GC-coated IONPs were subsequently characterized and evaluated for their antibacterial activity. Comparison of Fourier transform infrared spectra and thermogravimetric data of bare and GC-coated IONPs confirmed the presence of GC coating on IONPs. Magnetization curves showed that both bare and GC-coated IONPs are superparamagnetic and have saturation magnetizations of 70.3 and 59.8 emu g−1, respectively. The IONP size was measured as ∼8–9 nm by transmission electron microscopy, and their crystal structure was assigned to magnetite from x-ray diffraction patterns. Both bare and GC-coated IONPs inhibited the growths of Escherichia coli ATCC 8739 and Salmonella enteritidis SE 01 bacteria better than the antibiotics linezolid and cefaclor, as evaluated by the agar dilution assay. GC-coated IONPs showed higher potency against E. coli O157:H7 and Staphylococcus aureus ATCC 10832 than bare IONPs. Given their biocompatibility and antibacterial properties, GC-coated IONPs are a potential nanomaterial for in vivo applications.