As-synthesized Magnetic Nanoparticles Research Articles

Application of biocompatible and ultrastable superparamagnetic iron(III) oxide nanoparticles doped with magnesium for efficient magnetic fluid hyperthermia in lung cancer cells.

Magnetic fluid hyperthermia (MFH) is a promising therapeutic strategy that targets malignant tissues by heating to 40-43 °C using magnetic nanoparticles (MNPs) subjected to an alternating magnetic field (AMF). In this study, novel magnetic iron(III) oxide nanoparticles doped with magnesium (Mg0.1-γ-Fe2O3(mPEG-silane)0.5) were synthesized, and their structural, chemical, and magnetic properties were analyzed using the following techniques: Fourier-transform infrared spectroscopy, Raman spectroscopy, vibrating magnetometer analysis, powder X-ray diffraction, inductively coupled plasma mass spectrometry, scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The as-synthesized MNPs were used as water ferrofluids for MFH under an AMF in two calorimetric setups, namely phantom and lung cancer cell (A549) models. The as-synthesized MNPs were hexagonal or rhombohedral shaped, with an average size of 27 nm. They showed a typical soft ferromagnetic behavior based on the hysteresis profile, with a magnetic saturation of 70 emu g-1 and remnant magnetization of 1.6 emu g-1. In phantom studies, the ferrofluid (3.0 mg mL-1) exposed to an AMF (18.3 kA m-1, 110.1 kHz) heated up extremely quickly, reaching more than 90 °C in the first 10 min of magnetization. In cell studies, the ferrofluid (0.25 mg mL-1) under an AMF (16.7 kA m-1, 110.1 kHz) showed a slight increase in temperature within the first 12 min, reaching a peak of ca. 43-45 °C, which was stable up to the end of the AMF exposure (45 min). Under these conditions, a pronounced cytotoxic effect on the lung cancer cells was observed (viability ca. 15-20%). No such deleterious effects were observed when the cells were treated with MNPs only without an AMF. Specific absorption rate (SAR) measurements were performed using three mathematical approaches, namely the initial slope method, the corrected slope method, and the Box-Lucas method, which ranged from ca. 429 to 596 W g-1 for phantom and cell studies. Iron(III) oxide MNPs doped with magnesium were found to be candidates for MFH in lung cancer treatments.

Preparation of magnetic ferrite by optimizing the synthetic pH and its application for the removal of Cd(II) from Cd-NH3-H2O system

The magnetic ferrite nanoparticles were prepared using ferrous ions in aqueous solutions at various pH values (9, 10, 11 and 12) at 25 °C, labeled F9, F10, F11 and F12. The as-synthesized magnetic nanoparticles were characterized by settling velocity, Fe2+/Fe3+ ratio, laser particles size analyzer, vibrating sample magnetometer, X-ray diffraction and scanning electron microscopy. F9 had a settling velocity of 2% and a saturation magnetization of 82.30 emu/g, suggesting that it can be easily separated from water at a magnetic field. F9 was successfully applied to the adsorption of Cd(II) ions from Cd-NH3-H2O system. The effects of solution pH, contact time and NH3-N concentration were investigated. NH3-N in solution can hinder the adsorption of Cd(II) ions. The adsorption of Cd onto magnetic ferrite nanoparticles followed the pseudo-second order kinetics and the Langmuir isotherm model. The maximum adsorption capacities were 44.13 mg/g for the control group and 40.75 mg/g for the sample group. According to the cost analysis, the magnetic ferrite can be used as a cost-effective adsorbent.

Removal of Cu<sup>2+</sup> from Aqueous Solutions by Magnetic Nanoparticles-Pomelo Peel Composite

Many researchers have currently interested in using Fe3O4 magnetic nanoparticles (MNPs) impregnated onto agricultural wastes for removal of heavy metal ions in wastewater treatment process. In this work, the MNPs-pomelo peel powder (MNPs-PP) composites were developed and their adsorption capacities of heavy metal ions were studied as well. The MNPs-PP samples were synthesized by co-precipitation method in different ratios; 2:1, 2:2, 2:4, 2:5, and 2:6 (by weight). The results showed that the as-synthesized MNPs were mainly spherical shape with an average particle size of approximately 12.7 ± 0.6 nm. Then, the MNPs, PP and MNPs-PP in different ratios were used as adsorbents for adsorption of 25 ppm Cu2+ in aqueous solution. The pH and temperature of solution were kept constant at 5 and 30 °C, respectively. From the experiment, it was found that the adsorption capacities decreased in the following order: PP > MNPs-PP (2:6) > MNPs-PP (2:5) > MNPs-PP (2:4) > MNPs-PP (2:2) > MNPs-PP (2:1) > MNPs. It indicated that the adsorption capacity of as-synthesized MNPs-PP is significantly higher than that of sole MNPs. Furthermore, the adsorption capacities of MNPs-PP increased with increasing the weight ratio of PP. The MNPs-PP developed herein has demonstrated not only high adsorption efficiency but also have shown additional benefits such as ease to synthesis, cost-effectiveness, environmental-friendliness, and ease to separate from treated water by an external magnet.

Covalent Immobilization of Biotin on Magnetic Nanoparticles: Synthesis, Characterization, and Cytotoxicity Studies.

A simple protocol for covalent immobilization of biotin onto the surface of Fe3O4 magnetic nanoparticles (MNPs) for improving the biocompatibility of original MNPs has been realized. MNPs were first prepared by co-precipitation method which was subsequently anchored with functionalized biotin. The as-synthesized MNPs were observed to be monocrystalline as evidenced from XRD and TEM images. The covalent grafting of biotin to MNPs was confirmed by FT-IR. The XPS analysis suggested the successful preparation of Biotin-f-MNPs. The as-synthesized Biotin-f-MNPs were found to be superparamagnetic character as recorded by SQUID. Cell viability studies revealed that the biocompatibility of MNPs was improved upon Biotin immobilization.

Preparation and characterization of magnetic nanoparticles for the on-line determination of gold, palladium, and platinum in mine samples based on flow injection micro-column preconcentration coupled with graphite furnace atomic absorption spectrometry

A simple and highly selective procedure for on-line determination of trace levels of Au, Pd, and Pt in mine samples has been developed using flow injection-column adsorption preconcentration coupled with graphite furnace atomic absorption spectrophotometry (FI-column-GFAAS). The precious metals were adsorbed on the as-synthesized magnetic nanoparticles functionalized with 4'-aminobenzo-15-crown-5-ether packed into a micro-column and then eluted with 2% thiourea + 0.1 mol L(-1) HCl solution prior to the determination by GFAAS. The properties of the magnetic adsorbents were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). Various experimental parameters affecting the preconcentration of Au, Pd, and Pt were investigated and optimized. Under the optimal experimental conditions, the detection limits of the developed technique were 0.16 ng mL(-1) for Au, 0.28 ng mL(-1) for Pd, and 1.01 ng mL(-1) for Pt, with enrichment factors of 24.3, 13.9, and 17.8, respectively. Precisions, evaluated as repeatability of results, were 1.1%, 3.9%, and 4.4% respectively for Au, Pd, and Pt. The developed method was validated by the analysis of Au, Pd, and Pt in certified reference materials and mine samples with satisfactory results.

Selective recognition and separation of nucleosides using carboxymethyl-β-cyclodextrin functionalized hybrid magnetic nanoparticles

A novel magnetic nanoadsorbent (CMCD-APTS-MNPs) containing the superparamagnetic and molecular recognition properties was synthesized by grafting carboxymethyl-β-cyclodextrin (CM-β-CD) on 3-aminopropyltriethoxysile (APTS) modified Fe3O4 nanoparticles. The feasibility of using CMCD-APTS-MNPs as magnetic nanoadsorbent for selective adsorption of adenosine (A) and guanosine (G) based on inclusion and molecular recognition was demonstrated. The as-synthesized magnetic nanoparticles were characterized by TEM, FTIR and TGA analyses. The effects of pH and initial nucleoside concentrations on the adsorption behavior were studied. The complexation of CMCD-APTS-MNPs with both nucleosides was found to follow the Langmuir adsorption isotherm. The CMCD-APTS-MNPs showed a higher adsorption ability and selectivity for G than A under identical experimental conditions, which results from the ability of selective binding and recognition of the immobilized CM-β-CD towards G. The driving force of the separation between G and A is through the different weak interaction with grafted CM-β-CD, i.e., hydrogen bond interaction, which is evidenced by different inclusion equilibrium constants and FTIR analyses of inclusion complexes between grafted cyclodextrin and the guest molecules. Our results indicated that this nanoadsorbent would be a promising tool for easy, fast and selective separation, analysis of nucleosides and nucleotides in biological samples.