Growth Of Fe3O4 Nanoparticles Research Articles

A pH-sensitive magnetic hydrogel nanocomposite based on alginate for controlled release of methotrexate

Development of a carrier with controlled release manner for methotrexate (MTX), an anticancer drug with short elimination half-life of 3-10 h, is important to overcome undesired side effects of conventional systems. This study demonstrated the synthesis of a pH-sensitive magnetic hydrogel nanocomposite based on montmorillonite (MMT), magnetite (Fe3O4), and alginate (Alg) for extended release of MTX. MMT-Fe3O4 with different amounts of MMT, were prepared by growth of Fe3O4 nanoparticles on the surface of MMT. Then, the MMT-Fe3O4-MTX-Alg nanocomposite beads were prepared by coating of well dispersed MMT-Fe3O4-MTX with Alg. The characterization was investigated using FTIR, XRD, DLS, FESEM-EDX, TGA, and VSM techniques. By introducing 1 g of MMT in hydrogel beads, the encapsulation efficiency and loading content were enhanced to 99.34% and 18.71%, respectively. Pure drug exhibits a burst release of 100% within 4 h. Whereas for MMT (1)-Fe3O4-MTX-Alg, less burst release of 12.4% and 27.6% in the gastric and intestinal fluid was obtained, respectively within 4 h. This phenomenon leads to the beads remaining intact passing through the stomach, but the release rate is done at an acceptable rate at the relatively alkaline environment of the intestine. The release kinetics of MTX from the nanocomposite beads follows the Korsmeyer-Peppas model. Finally, MTT assay and RT-PCR analysis were followed on MDA-MB-231 breast cancer cells, to assess their anti-proliferative, apoptotic and antiapoptotic effects. MMT-Fe3O4-MTX-Alg significantly reduced the percentage of viable cells, with a high down-regulation in the expression level of the anti-apoptotic gene (Bcl-2), and up-regulation in the apoptotic gene (Bax).

Photothermal Nanozyme-Based Microneedle Patch against Refractory Bacterial Biofilm Infection via Iron-Actuated Janus Ion Therapy.

Owing to high antibiotic resistance and thermotolerance, bacterial biofilm infections (BBIs) are refractory to elimination. Iron is essential for bacterial growth and metabolism, and bacteria can thus accumulate iron from surrounding cells to maintain biofilm formation and survival. Consequently, iron deficiency in the biofilm microenvironment (BME) leads to the functional failure of innate immune cells. Herein, a novel antibiofilm strategy of iron-actuated Janus ion therapy (IJIT) is proposed to regulate iron metabolism in both bacterial biofilm and immune cells. A BME-responsive photothermal microneedle patch (FGO@MN) is synthesized by the growth of Fe3 O4 nanoparticles on graphene oxide nanosheets and then encapsulated in methacrylated hyaluronic acid needle tips. The catalytic product of ·OH by FGO@MN in BME disrupts the bacterial heat-shock proteins, coercing biofilm thermal sensitization. As synergistic mild photothermal treatment triggers iron uptake, the intracellular iron overload further induces ferroptosis-like death. Moreover, iron-nourished neutrophils around BME can be rejuvenated for reactivating the suppressed antibiofilm function. Thus, more than 95% BBIs elimination can be achieved by combining heat stress-triggered iron interference with iron-nutrient immune reactivation. Furthermore, in vivo experiments validate the scavenging of refractory BBI after 15days, suggesting the promising perspective of IJIT in future clinical application.

Fabrication of Magnetic Cenosphere Deposited with Fe<sub>3</sub>O<sub>4</sub> Nanoparticles by Hydrothermal Method

We prepared the magnetic cenospheres deposited with magnetite Fe3O4 nanoparticles under hydrothermal conditions. The crystalline phase, magnetization properties, morphology, chemical composition and thermal stability of asobtained cenospheres are analyzed by Xray diffraction, vibrating sample magnetometer, scanning electron microscope, Xray energy dispersive spectroscope, transmission electron microscope, thermal gravimetric analysis and differential scanning calorimetry techniques. The results show that the inverse cubic spinel phase of Fe3O4 nanoparticles with an average size 50 nm are synthesized, and synchronously deposited on cenosphere surface. As the thickness of Fe3O4 coating increases, the saturation magnetization increases to some extent. The growth of Fe3O4 nanoparticles can be controlled by adding ethanol to the reaction solution.

Fe3O4 nanoparticles grown on graphene as advanced electrode materials for supercapacitors

A novel composite of magnetite (Fe3O4) nanoparticles (NPs) grown on reduced graphene oxide (rGO) has been synthesized by a facile hydrothermal technique without any surfactants or templates. In this method, the growth of Fe3O4 NPs and the reduction of graphene oxide (GO) are completed in one single step. Moreover, we have prepared Fe3O4 microcubes and Fe3O4/carbon nanotubes (CNTs) composite under the same condition. The electrochemical properties of the as-prepared samples are investigated as advanced electrode materials for supercapacitors. It is found that the Fe3O4/rGO nanocomposite displays much higher specific capacitances and better cycle stability than those of pure Fe3O4 and Fe3O4/CNTs composite. Specifically, it exhibits a high specific discharge capacitance of 220.1 F g−1 at 0.5 A g−1 and remains stable after 3000 charge/discharge cycles. The improvement of the electrochemical performances of Fe3O4/rGO may be attributed to the chemical interaction between rGO and Fe3O4, lower agglomeration and smaller particle size of Fe3O4.

Preparation and characterization of magnetic nanoparticles of Fe3O4 coated with mesoporous SiO2

We prepared the magnetic nanoparticles of Fe3O4from thermal decomposition of the Fe oleates precursors synthesized by iron chlorides and sodium oleate,and the SiO2-coated Fe3O4nanoparticles by combining the reverse microemulsion and organic template methods. FTIR was adopted to investigate the surface of Fe oleate under different treatments,and the growth of Fe3O4 nanoparticles with different reactant concentrations of oleic acid and heating rates. The results indicated that the superficial oleic acid of the waxy solid Fe oleates after extraction from ethanol and acetone was partially removed,which impairs the formation of monodispersion Fe3O4 naoparticles. The effect of heating rate on the growth of nanoparticles was weak compared with that of the concentration of Fe oleates. When the concentration of oleic acid is 0.09 mol/L, a characteristic peak of Fe3O4 at 576 cm-1(assignable to the bending vibrations of Fe-O) is enhanced significantly. The XRD (X-ray diffraction) spectra,TEM (transmission electron microscopy) images and SQUID (superconducting quantum interference device) confirmed that the Fe3O4 nanoparticles are spinel cubic crystal and have a good monodispersity and super-paramagnetism. Whats more,the TEM of SiO2-coated Fe3O4 nanoparticles also confirmed that the Fe3O4 nanoparticles were well coated by mesoporous SiO2.