Magnetic Composite Nanomaterials Research Articles

Synthesis and characterization of the sea urchin-like γ-AlOOH/Fe3O4@SiO2 nanosorbent with ultra-high performance of Congo red removal

To manifest the benefits of nanosorbents in microstructure, the strong magnetism of Fe3O4 nanospheres is fully utilized to realize the rapid solid–liquid separation of adsorbent and aqueous solution. A sea urchin-like magnetic composite nanosorbent with a hierarchical structure was successfully manufactured by a simple and efficient liquid-phase hydrothermal synthesis method. Furthermore, its graded structure can sufficiently enhance the porosity and Zeta potential value of the material to increase the adsorption site and adsorption force between the material and CR molecular. The synthesized nanosorbent was then explored by a series of material physical and chemical characterization tools. It can be illustrated that the adsorbent is a strong magnetic composite nanomaterial with uniform particle size distribution and high dispersion, and is based on Fe3O4@SiO2 smooth nanoparticles as the inner core and γ-AlOOH as the shell. The saturation adsorption capacity reached 4534.57 mg g−1 with due expedition (under the adsorbent mass of 50 mg, CR mass concentration of 1500 mg/L, temperature of 25 °C and solution pH value of 3), whereas the γ-AlOOH of 925.34 mg g−1, Fe3O4 of 41.25 mg g−1 and Fe3O4@SiO2 of 93.21 mg g−1. After eight cycles of adsorption tests, the saturation capacity could still maintain 94.46% of the original adsorption capacity. Moreover, the adsorbent could be recovered by a simple applied magnetic field and the whole adsorption process conforms to the Pseudo-second kinetic model and the Langmuir isotherm model. Therefore, the sea urchin-like magnetic composite nanomaterials with a graded structure synthesized in this study could be widely utilized as a potential adsorbent material for CR removal.

Compare the Effects of Magnolol on Gastric Cancer Cells Through c-Jun N-Terminal Kinase Signaling Pathway and Gold Magnetic.

This article explores the effects and mechanisms of magnolol on the proliferation of gastric cancer cells as well as the apoptosis. First, 0 (control group), 20, 40, and 80 /x mol/L magnolol were observed on SGC-7901 cells for 24, 48, and 72 h. We use MTT method to measure the cell viability, and apoptosis and cells were detected by flow cytometry. Cell proliferation inhibition rate, apoptosis and cell cycle experiments showed that P-value < 0.05 means the difference is statistically significant. And the results which compare the control group, the 20, 40, and 80 /x mol/L show that honokiol had lower cell viability (P < 0.01), increased apoptotic rate (P < 0.01), and cell cycle stay in the G1 phase (P < 0.01), so we found that honokiol may suppress the proliferation of SGC-7901 cells and stimulate apoptosis by regulating cyclin and apoptosis-related proteins. With the development of nanomaterials synthesis technology and application in biomedicine, gold magnetic composite nanomaterials have unique properties, so they have been widely concerned in many applications. We combine gold and magnetic nanomaterials through other nanostructures to achieve the integration of diagnosis and treatment of tumors. We have synthesized two kinds of gold magnetic nanocomposites, GNR-PPy-FA nanocomposites. With the role of chemotherapy and heat and light therapy, GNR-PPy-FA nanocomposites have high light-to-heat conversion efficiency. Cell experiments verify the effect of chemotherapy and photothermal treatment of composite nanomaterials. After incubation with gold magnetic composite nanomaterials, the cell survival rate of tumor cells decreased to about 15%. In addition, both types of gold magnetic nanocomposites have the ability to dually target cancer cells, and the modification of folic acid and cancer cell membranes makes the material more biocompatible.

Maximizing surface-enhanced Raman scattering sensitivity of surfactant-free Ag-Fe3O4 nanocomposites through optimization of silver nanoparticle density and magnetic self-assembly

Magnetic composite nanomaterials consisting of more than two functional constituents have been attracting much research interests due to the realization of multiple functionalities in a single entity. In particular, integration of ferromagnetic oxides and noble metal nanoparticles (NPs) in composites results in simultaneous magnetic activity and optical response where the optical property of the whole system could be modulated by application of an external magnetic field. In this work, we prepared Ag NPs-coated Fe3O4 microspheres as a novel surfactant-free surface-enhanced Raman scattering (SERS) substrate through a solid-phase thermal decomposition reaction. The SERS sensitivity of the fabricated nanocomposites is maximized by adjusting the size and density of Ag NPs supported on the Fe3O4 microspheres and further increased by magnetic-field-directed self-assembly of the composite substrates, with both effects attributed to the efficient generation of plasmonic near-field “hot” spots. At the optimal conditions, the prepared substrate is capable of detecting rhodamine 6G molecules at a concentration down to 10−12 M, thus demonstrating the great potential of using bifunctional nanocomposites as an excellent candidate for ultra-high sensitive Raman spectroscopy and biosensors. We also reveal the underlying mechanisms responsible for the observed SERS enhancements through full-wave numerical simulations.

Water dispersible cross-linked magnetic chitosan beads for increasing the antimicrobial efficiency of aminoglycoside antibiotics

The aim of this study was to obtain a nano-active system to improve antibiotic activity of certain drugs by controlling their release. Magnetic composite nanomaterials based on magnetite core and cross-linked chitosan shell were synthesized via the co-precipitation method and characterized by Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The prepared magnetic composite nanomaterials exhibit a significant potentiating effect on the activity of two cationic (kanamycin and neomycin) drugs, reducing the amount of antibiotics necessary for the antimicrobial effect. The increase in the antimicrobial activity was explained by the fact that the obtained nanosystems provide higher surface area to volume ratio, resulting into higher surface charge density thus increasing affinity to microbial cell and also by controlling their release. In addition to the nano-effect, the positive zeta potential of the synthesized magnetite/cross-linked chitosan core/shell magnetic nanoparticles allows for a more favorable interaction with the usually negatively charged cell wall of bacteria. The novelty of the present contribution is just the revealing of this synergistic effect exhibited by the synthesized water dispersible magnetic nanocomposites on the activity of different antibiotics against Gram-positive and Gram-negative bacterial strains. The results obtained in this study recommend these magnetic water dispersible nanocomposite materials for applications in the prevention and treatment of infectious diseases.

Thermoresponsive magnetic composite nanomaterials for multimodal cancer therapy

The synthesis, characterization and property evaluation of drug-loaded polymer-coated magnetic nanoparticles (MNPs) relevant to multimodal cancer therapy has been studied. The hyperthermia and controlled drug release characteristics of these particles was examined. Magnetite (Fe 3O 4)–poly- n-(isopropylacrylamide) (PNIPAM) composite MNPs were synthesized in a core–shell morphology by dispersion polymerization of n-(isopropylacrylamide) chains in the presence of a magnetite ferrofluid. These core–shell composite particles, with a core diameter of ∼13 nm, were loaded with the anti-cancer drug doxorubicin (dox), and the resulting composite nanoparticles (CNPs) exhibit thermoresponsive properties. The magnetic properties of the composite particles are close to those of the uncoated magnetic particles. In an alternating magnetic field (AMF), composite particles loaded with 4.15 wt.% dox exhibit excellent heating properties as well as simultaneous drug release. Drug release testing confirmed that release was much higher above the lower critical solution temperature (LCST) of the CNP, with a release of up to 78.1% of bound dox in 29 h. Controlled drug release testing of the particles reveals that the thermoresponsive property can act as an on/off switch by blocking drug release below the LCST. Our work suggests that these dox-loaded polymer-coated MNPs show excellent in vitro hyperthermia and drug release behavior, with the ability to release drugs in the presence of AMF, and the potential to act as agents for combined targeting, hyperthermia and controlled drug release treatment of cancer.