Amount Of Magnetite Nanoparticles Research Articles

Composite magnetic 3D-printing filament fabrication protocol opens new perspectives in magnetic hyperthermia

Three-dimensional (3D) printing technology has emerged as a promising tool for meticulously fabricated scaffolds with high precision and accuracy, resulting in intricately detailed biomimetic 3D structures. Producing magnetic scaffolds with the aid of additive processes, known as 3D printing, reveals multitude and state-of-the-art areas of application such as tissue engineering, bone repair and regeneration, drug delivery and magnetic hyperthermia. A crucial first step is the development of innovative polymeric composite magnetic materials. The current work presents a fabrication protocol of 3D printed polymer-bonded magnets using the Fused Deposition Modeling 3D printing method. Polymer-bonded magnets are defined as composites with permanent-magnet powder embedded in a polymer binder matrix. By using a low-cost mixing extruder, four (4) different filament types of 1.75 mm were fabricated using commercial magnetite magnetic nanoparticles mixed with a pure polylactic acid powder (PLA) and a ferromagnetic PLA (Iron particles included) filaments. The powder mixture of the basic filaments was compounded mixed with the nanoparticles (NPs), and extruded to fabricate the 3D printing filament, which is subsequently characterized structurally and magnetically before the printing process. Magnetic polymer scaffolds are finally printed using composite filaments of different concentration in magnetite. Our results demonstrate that the heating efficiency (expressed in W g−1) of the 3D printed magnetic polymer scaffolds (ranging from 2 to 5.5 W g−1 at magnetic field intensity of 30 mT and field frequency of 365 kHz) can be tuned by choosing either a magnetic or a non-magnetic filament mixed with an amount of magnetite NPs in different concentrations of 10 or 20 wt%. Our work opens up new perspectives for future research, such as the fabrication of complex structures with suitable ferromagnetic custom-made filaments adjusting the mixing of different filaments for the construction of scaffolds aimed at improving the accuracy of magnetic hyperthermia treatment.

A porous calcium-zirconia scaffolds composed of magnetic nanoparticles for bone cancer treatment: Fabrication, characterization and FEM analysis

One of the most critical challenges in tissue engineering is the fabrication of porous scaffolds with high porosity and proper mechanical properties. Conventional synthetic scaffolds are typically made of ceramic composed with other ceramics; however, a better combination of nanocomposite can be obtained using magnetite nanoparticles (MNPs), which benefits both ceramic materials. The current study used the space holder method and mechanical activation to create a porous magnetic-zirconia calcium bio-nanocomposite scaffold for bone tissue applications. The samples were made with varying amounts of reinforcement (0, 5, 10, and 15 wt%). The addition of sodium chloride has the main effect on the porosity size of the architecture. The prepared magnetic-zirconia calcium bio-nanocomposite scaffold was coated with a 5% solution of chitosan polymer, and its mechanical and biological properties were investigated. Powders and scaffolds were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The cell viability and non-toxicity of porous scaffolds were evaluated by MTT assay. The results showed that the addition of 15 wt% of MNPs changed the mechanical and biological properties of the composite scaffold. According to the SEM results, addition of 15% MNPs did not significantly change the porosity. However, it improves the porosity percentages. After being placed in the simulated body fluid (SBF), SEM images of the scaffolds showed the formation of a bone-like apatite layer on the surfaces of the sample with a higher amount of MNPs. Biocompatibility assessment by MTT test showed that composite scaffolds did not show any toxicity in contact with bone marrow stem cells and increased cell growth and proliferation. The mechanical simulation shows that the specimen's mechanical strength can be predicted by low error and can be a suitable option for bone tissue engineering applications.

Nanomagnetite-embedded PLGA Spheres for Multipurpose Medical Applications.

We report on the synthesis and evaluation of biopolymeric spheres of poly(lactide-co-glycolide) containing different amounts of magnetite nanoparticles and Ibuprofen (PLGA-Fe3O4-IBUP), but also chitosan (PLGA-CS-Fe3O4-IBUP), to be considered as drug delivery systems. Besides morphological, structural, and compositional characterizations, the PLGA-Fe3O4-IBUP composite microspheres were subjected to drug release studies, performed both under biomimetically-simulated dynamic conditions and under external radiofrequency magnetic fields. The experimental data resulted by performing the drug release studies evidenced that PLGA-Fe3O4-IBUP microspheres with the lowest contents of Fe3O4 nanoparticles are optimal candidates for triggered drug release under external stimulation related to hyperthermia effect. The as-selected microspheres and their chitosan-containing counterparts were biologically assessed on macrophage cultures, being evaluated as biocompatible and bioactive materials that are able to promote cellular adhesion and proliferation. The composite biopolymeric spheres resulted in inhibited microbial growth and biofilm formation, as assessed against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans microbial strains. Significantly improved antimicrobial effects were reported in the case of chitosan-containing biomaterials, regardless of the microorganisms’ type. The nanostructured composite biopolymeric spheres evidenced proper characteristics as prolonged and controlled drug release platforms for multipurpose biomedical applications.

Determination of indium using vortex assisted solid phase microextraction based on oleic acid coated magnetic nanoparticles combined with slotted quartz tube-flame atomic absorption spectrometry

A solid phase microextraction (SPME) method combined with slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) was developed and optimized for the extraction and the determination of trace indium in different matrices. The method relies upon SPME that uses oleic acid coated magnetite nanoparticles (MNPs) followed by analysis with SQT mounted FAAS. After the enhancement in sensitivity by means of SPME, further improvement in sensitivity was provided by SQT which improves the detection power of conventional FAAS. The easy separation of extracted indium from the media was facilitated using an external magnetic field. Some effective parameters on the development of the method such as pH of the analyte solution, amount of eluent, amount of MNPs were optimized to obtain maximum absorbance value at each optimization step in order to achieve an improved detection power. Under the optimum experimental and instrumental conditions, the enhancement factor of 44 was obtained where the limit of detection and the limit of quantification were found to be 6.02 μg/L and 20.06 μg/L, respectively. Recovery tests were also studied in order to demonstrate the accuracy of the developed analytical method and satisfactory outcomes were obtained.

Effect on the Formation of Magnetite Reduced Graphene Oxide with Controlled Stirring Duration

Graphene is a promising material due to its fascinating properties, such as mechanical, electronic and thermal properties. Graphene based hybrids materials also have been widely studied due to its wide applications, such as sensors, energy storage and conversion, electronic device and others. The current study presents the synthesis of magnetite-reduced graphene oxide (M-rGO) nanocomposites through in situ chemical synthesis at different stirring durations. This synthesis process involves the redox reaction between the iron(II) salts and graphene oxide (GO) sheets. Various techniques were employed to characterize the synthesized M-rGO nanocomposites. From X-ray diffraction (XRD) results, the crystal structure of M-rGO was found to be independent on the stirring duration. Three magnetite vibrations, D band and G band were observed in Raman spectrum of M-rGO with 24 hours stirring duration. From Fourier transform infrared (FTIR) analysis, M-rGO with 24 hours stirring duration showed the strong intensity of Fe-O vibration. Thus, this indicated that a large amount of magnetite nanoparticles were covered on the surface of rGO sheets. This result is further supported by the morphology of nanocomposites from scanning electron microscopy (SEM) and the elemental analysis (EDX). A monolayer of rGO sheet (C= 33.79 atomic %) with full coverage of magnetite nanoparticles (Fe= 30.20 atomic %) was found for the M-rGO with 24 hours stirring duration. Overall, M-rGO require 24 hours of continuous stirring to ensure full coverage of magnetite nanoparticles on the surface of rGO sheets.

Effective induction of death in mesothelioma cells with magnetite nanoparticles under an alternating magnetic field

With the objective of finding an avenue for development of magnetic hyperthermia as an effective mesothelioma treatment, the influence of heating by magnetite nanoparticles (MNPs) with a diameter of ~40nm, which were incorporated into cells and then subjected to AC magnetic field, on induction of cell death was investigated in all three histological subtypes of human mesothelioma cells (i.e., epithelioid NCI-H28, sarcomatoid NCI-H2052, and biphasic MSTO-211H cells). Cellular uptake of MNPs was observed in all cell types, but the amount of MNPs incorporated per cell into MSTO-211H cells was smaller than in NCI-H28 and NCI-H2052 cells. On the other hand, cell death induced by cellular uptake of MNPs was observed specifically in MSTO-211H cells. Hence, when cells are heated by intracellular MNPs under AC magnetic field, a high degree of cell mortality in NCI-H28 and NCI-H2052 cells is induced by the temperature increase derived from the high amount of intracellular MNPs, but the combination of intracellular heating and cell-type-specific toxicity of MNPs induced high rates of cell death in MSTO-211H cells even at a lower temperature. Almost all of the heated cells were dead after 24-h incubation at 37°C in all histological subtypes. Additionally, higher mortalities were observed in all three types of mesothelioma cells after MNPs-heating, as compared to the heating with a thermostatic bath. Herein, the significance of cellular uptake of MNPs for effectively inducing cell death in mesothelioma has been demonstrated in vitro.

A novel bioelectrode and anaerobic sludge coupled system for p-ClNB degradation by magnetite nanoparticles addition.

A novel laboratory-scale bioelectrode and anaerobic sludge coupled system was established for the enhancement of p-chloronitrobenzenes (p-ClNB) reductive transformation with addition of magnetite nanoparticles. In this coupled system, the bioelectrodes were supplied with a voltage of 0.8V and the amount of magnetite nanoparticles was set at 7.4mL/400mL. Results showed that high p-ClNB transformation rate of 0.284h-1 and high p-chloroaniline (p-ClAn) dechlorination rate of 0.082h-1 were achieved in the coupled system at p-ClNB initial concentration of 30mgL-1, and p-ClAn is one of the reductive products of p-ClNB. The cyclic voltammetry curve showed that when the potential was -1000mV, the magnetite-biocathode current was about 10.7 times of the abiotic cathode. Also, a shift in the reductive peak potential and a dramatic increase in reductive peak current were observed. These findings suggest that magnetite nanoparticles could enhance the electrocatalytic activity and may act as electron conduits between microorganisms or between electrodes and microorganisms to promote the extracellular electron transfer.

Enhanced stability and photocatalytic performance of transition metal-doped ZnO with magnetite nanoparticle and zeolite

The combination of zeolite and transition metal-doped ZnO nanoparticles for improved electron and hole photogeneration and inhibited electron-hole recombination, due to the trapping states, has been studied in our previous work. However, the photocatalyst has not been separated and reused after successfully degrading the organic dye. Therefore, in this study, we incorporated four different variations of magnetite nanoparticles into zeolite-supported Fe-doped ZnO, using the co-precipitation method. The samples were characterized with the aid of various measurements, such as x-ray diffraction, infrared absorption, diffuse reflectance spectroscopy, vibrating sample magnetometer (VSM), and Burneur-Emment-Teller (BET). The photocatalytic activity of nanocomposites was examined by photodegradation of methylene blue under UV light irradiation. The results show that the presence of a certain amount of magnetite nanoparticles in a zeolite-supported Fe-doped ZnO nanocomposite improved its efficiency in degrading methylene blue. The role of charged carriers and the active radical involved in the photocatalytic activity is discussed.

Naked magnetite nanoparticles for both clean-up and solid-phase extraction-trace determination of mercury

A new solid-phase extraction method was developed for trace determination of Hg(II) by using a small amount of naked magnetite nanoparticles as an adsorbent. The magnetite nanoparticles were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The adsorbed Hg(II)-dithizone complex was eluted with 1.0 mL aliquot of an acidic 1-propanol solution prior to electrothermal atomic absorption spectrometry. A huge positive effect was found on the mercury adsorption by ionic strength. Under optimized condition, a linear calibration curve was obtained for mercury in the range of 0.2–50 ng mL−1 with relative standard deviation in the range of 0.5–2.0%. The limit of detection and enrichment factor were 0.01 ng mL−1 and 98.3, respectively. The effects of coexisting ions were studied extensively, and a new clean-up procedure was used to remove the matrix effects by using a simple sample pretreatment step using a little amount of magnetite nanoparticles. The method was successfully applied to the determination of Hg(II) in different water and human urine samples and a commercial sodium nitrate.

Super-paramagnetic responsive silk fibroin/chitosan/magnetite scaffolds with tunable pore structures for bone tissue engineering applications

Tissue engineering is a promising approach in repairing damaged tissues. During the last few years, magnetic nanoparticles have been of great interest in this field of study due to their controlled responsive characteristics in specific external magnetic fields. In this study, after synthesizing iron oxide (magnetite) nanoparticles through a reverse coprecipitation method, silk fibroin/chitosan-based magnetic scaffolds were prepared using different amounts of magnetite nanoparticles (0, 0.5, 1 and 2%) by freeze-casting method. The physicochemical activity of the scaffolds was monitored in phosphate-buffered saline (PBS) solution to determine the biodegradation and swelling behaviors. The stability of the magnetite nanoparticles in the fabricated scaffolds was determined by atomic absorption spectroscopy (AAS). Moreover, the cellular activity of the magnetic scaffolds was examined under a static magnetic field. The results showed that the lamellar structured scaffolds having MNPs in the walls could not affect the final structure and deteriorate the biological characteristics of the scaffolds, while the ability of magnetic responsivity was added to the scaffolds. This study warrants further pre-clinical and clinical evaluations.

Multifunctional layered magnetic composites.

A fabrication method of a multifunctional hybrid material is achieved by using the insoluble organic nacre matrix of the Haliotis laevigata shell infiltrated with gelatin as a confined reaction environment. Inside this organic scaffold magnetite nanoparticles (MNPs) are synthesized. The amount of MNPs can be controlled through the synthesis protocol therefore mineral loadings starting from 15 wt % up to 65 wt % can be realized. The demineralized organic nacre matrix is characterized by small-angle and very-small-angle neutron scattering (SANS and VSANS) showing an unchanged organic matrix structure after demineralization compared to the original mineralized nacre reference. Light microscopy and confocal laser scanning microscopy studies of stained samples show the presence of insoluble proteins at the chitin surface but not between the chitin layers. Successful and homogeneous gelatin infiltration in between the chitin layers can be shown. The hybrid material is characterized by TEM and shows a layered structure filled with MNPs with a size of around 10 nm. Magnetic analysis of the material demonstrates superparamagnetic behavior as characteristic for the particle size. Simulation studies show the potential of collagen and chitin to act as nucleators, where there is a slight preference of chitin over collagen as a nucleator for magnetite. Colloidal-probe AFM measurements demonstrate that introduction of a ferrogel into the chitin matrix leads to a certain increase in the stiffness of the composite material.

In Vitro Studies of Bacterial Cellulose and Magnetic Nanoparticles Smart Nanocomposites for Efficient Chronic Wounds Healing.

The quality of life of patients with chronic wounds can be extremely poor and, therefore, over the past decades, great efforts have been made to develop efficient strategies to improve the healing process and the social impact associated with these conditions. Cell based therapy, as a modern tissue engineering strategy, involves the design of 3D cell-scaffold bioconstructs obtained by preseeding drug loaded scaffolds with undifferentiated cells in order to achieve in situ functional de novo tissue. This paper reports on the development of bionanocomposites based on bacterial cellulose and magnetic nanoparticles (magnetite) for efficient chronic wounds healing. Composites were obtained directly in the cellulose bacterial culture medium by dispersing various amounts of magnetite nanoparticles during the biosynthesis process. After purification and drying, the membranes were characterized by Raman spectroscopy and X-ray diffraction to reveal the presence of magnetite within the bacterial cellulose matrix. Morphological investigation was employed through SEM and TEM analyses on bionanocomposites. The biocompatibility of these innovative materials was studied in relation to human adipose derived stem cells in terms of cellular morphology, viability, and proliferation as well as scaffolds cytotoxic potential.

Synergistic effect of magnetite nanoparticles and carbon nanofibres in electromagnetic absorbing composites

Epoxy composites with different amounts of magnetite nanoparticles, carbon nanofibres (CNF) and magnetite-decorated CNF were prepared and characterized. A simple method for the magnetite CNF decoration was developed by adsorbing preformed oleic acid capped-magnetite nanoparticles over the CNF surface. A synergy between magnetite nanoparticles and CNF was found to have crucial effects in the electromagnetic shielding efficiency of the prepared materials. This effect has been analysed by their electrical conductivity in terms of percolation theory and complex permittivity at high frequencies. Electromagnetic shielding mechanisms (reflection, absorption and transmission) were individually studied in the 1–18GHz range. Results show that decoration of CNF with magnetite, notably increases permittivity and high-frequency AC conductivity and enhances the electromagnetic shielding efficiency up to around 20dB at high frequencies. It is proposed that interfacial polarization adds an additional dissipation mechanism that may be responsible for the observed electromagnetic shielding enhancement.

The intensity of internalization and cytotoxicity of superparamagnetic iron oxide nanoparticles with different surface modifications in human tumor and diploid lung cells

The human lung adenocarcinoma epithelial (A549) cells and the human embryo lung (HEL 12469) cells were used to investigate the uptake and cytotoxicity of magnetite nanoparticles (MNPs) with different chemically modified surfaces. MNPs uptake was an energy-dependent process substantially affected by the serum concentration in the culture medium. Internalized MNPs localized in vesicle-bound aggregates were observed in the cytoplasm, none in the nucleus or in mitochondria. All MNPs induced a dose- and time-dependent increase in cytotoxicity in both human lung cell lines. The cytotoxicity of MNPs increased proportionally with the particle size. Since the cytotoxicity of MNPs was nearly identical when the doses were equalized based on particle surface area, we suppose that the particle surface area rather than the surface modifications per se underlay the cytotoxicity of MNPs. In general, higher internalized amount of MNPs was found in HEL 12469 cells compared with A549 cells. Accordingly, the viability of the human embryo lung cells was reduced more substantially than that of the adenocarcinoma lung cells. The weak MNPs uptake into A549 cells might be of biomedical relevance in cases where MNPs should be used as nanocarriers for targeted drug delivery in tumor tissue derived from alveolar epithelial cells.