Mesoporous Fe3O4 Nanoparticles Research Articles

Superoxide Dismutase-Like Regulated Fe/Ppa@PDA/B for Synergistically Targeting Ferroptosis/Apoptosis to Enhance Anti-Tumor Efficacy.

The cell apoptosis pathway of sonodynamic therapy (SDT) is usually blocked, resulting in limited therapeutic efficacy, therefore, the development of new methods for sensitizing targeted ferroptosis and promoting apoptosis is of great significance to improve the anti-tumor efficacy of SDT. Herein, mesoporous Fe3 O4 nanoparticles (NPs) are synthesized for loading pyropheophorbide-a (ppa), surface-coated by polydopamine (PDA) and further anchored with tumor-targeting moieties of biotin to obtain Fe/ppa@PDA/B NPs. Fe/ppa@PDA/B displayes pH/ultrasound (US) responsive release properties, and magnetic resonance imaging (MRI) functions. Moreover, Fe3 O4 NPs of Fe/ppa@PDA/B as the Fe source for ferroptosis, enhances ferroptosis sensitivity by consuming glutathione (GSH) and producing hydroxyl radical (OH). The quinone groups of PDA layer on Fe/ppa@PDA/B own free electrons, which led to effective superoxide dismutase (SOD) action through superoxide anion (O2 - ) disproportionation to hydrogen peroxide (H2 O2 ) and oxygen (O2 ), thus, overcame hypoxia of SDT and promoted ·OH generation by Fe ions under US trigger, synergistically improves ferroptosis and apoptosis to enhance the anti-tumor efficacy of SDT both in vitro and in vivo. The anti-tumor strategy of synergistic apoptosis and ferroptosis induce by GSH depletion and self-sufficient O2 regulated by SOD provides a new idea for enhancing SDT efficacy.

Magnetic Nanozyme Based on Loading Nitrogen-Doped Carbon Dots on Mesoporous Fe3O4 Nanoparticles for the Colorimetric Detection of Glucose.

The simple and accurate monitoring of blood glucose level is of great significance for the prevention and control of diabetes. In this work, a magnetic nanozyme was fabricated based on loading nitrogen-doped carbon dots (N-CDs) on mesoporous Fe3O4 nanoparticles for the colorimetric detection of glucose in human serum. Mesoporous Fe3O4 nanoparticles were easily synthesized using a solvothermal method, and N-CDs were then prepared in situ and loaded on the Fe3O4 nanoparticles, leading to a magnetic N-CDs/Fe3O4 nanocomposite. The N-CDs/Fe3O4 nanocomposite exhibited good peroxidase-like activity and could catalyze the oxidation of the colorless enzyme substrate 3,3',5,5'-tetramethylbenzidine (TMB) to blue TMB oxide (ox-TMB) in the presence of hydrogen peroxide (H2O2). When the N-CDs/Fe3O4 nanozyme was combined with glucose oxidase (Gox), Gox catalyzed the oxidization of glucose, producing H2O2 and leading to the oxidation of TMB under the catalysis of the N-CDs/Fe3O4 nanozyme. Based on this mechanism, a colorimetric sensor was constructed for the sensitive detection of glucose. The linear range for glucose detection was from 1 to 180 μM, and the limit of detection (LOD) was 0.56 μM. The recovered nanozyme through magnetic separation showed good reusability. The visual detection of glucose was also realized by preparing an integrated agarose hydrogel containing the N-CDs/Fe3O4 nanozyme, glucose oxidase, and TMB. The colorimetric detection platform has an enormous potential for the convenient detection of metabolites.

Tumor Microenvironment-Adaptive Nanoplatform Synergistically Enhances Cascaded Chemodynamic Therapy.

Chemodynamic therapy (CDT), a noninvasive strategy, has emerged as a promising alternative to conventional chemotherapy for treating tumors. However, its therapeutic effect is limited by the amount of H2O2, pH value, the hypoxic environment of tumors, and it has suboptimal tumor-targeting ability. In this study, tumor cell membrane-camouflaged mesoporous Fe3O4 nanoparticles loaded with perfluoropentane (PFP) and glucose oxidase (GOx) are used as a tumor microenvironment-adaptive nanoplatform (M-mFeP@O2-G), which synergistically enhances the antitumor effect of CDT. Mesoporous Fe3O4 nanoparticles are selected as inducers for photothermal and Fenton reactions and as nanocarriers. GOx depletes glucose within tumor cells for starving the cells, while producing H2O2 for subsequent ·OH generation. Moreover, PFP, which can carry O2, relieves hypoxia in tumor cells and provides O2 for the cascade reaction. Finally, the nanoparticles are camouflaged with osteosarcoma cell membranes, endowing the nanoparticles with homologous targeting and immune escape abilities. Both in vivo and in vitro evaluations reveal high synergistic therapeutic efficacy of M-mFeP@O2-G, with a desirable tumor-inhibition rate (90.50%), which indicates the great potential of this platform for clinical treating cancer.

Facile Synthesis of Amino-functionalized Mesoporous Fe3O4/rGO 3D Nanocomposite by Diamine compounds as Li-ion Battery Anodes

Being an essential part of lithium-ion batteries, the development of novel anode materials currently receives much attention. Among these, the high theoretical capacity of Fe3O4 (924 mAh g−1) makes it highly promising. However, massive volumetric changes and particle aggregation during repeated insertion/de-insertion of lithium ions damage the electrode structure and destroy the electrical connection with the current collectors, resulting in rapid and significant capacity losses. One strategy to overcome this problem is the employment of graphene-based compounds as a substrate in an interconnected porous conductive network using a crosslinker (e.g., ethylene diamine) to adjust the distance between the graphene layers. Such a 3D framework creates enough available space for the lithium ions to be inserted or de-inserted respectively to or from the electrode during the charge-discharge process. Moreover, this strategy prevents large electrode volume changes and the accumulation of Fe3O4 during cycling. Herein, an ex situ method was used to synthesize amino-functionalized mesoporous Fe3O4/graphene-based nanocomposites. In the first step, Fe3O4 nanoparticles were synthesized with the addition of ethylenediamine (EDA), whereby mesoporous Fe3O4 nanoparticles were obtained (Fe3O4-E). In the second step, Fe3O4-E/rGO nanocomposites were prepared with the help of electrostatic interactions. The Fe3O4-E/rGO nanocomposite showed good cycling performance vs. Li-metal and a high reversible capacity (∼465 mAh g−1) and average coulombic efficiency of ∼98% after 250 cycles at the current density of 1000 mA g−1. These promising results can be attributed to the presence of EDA in the formation of mesoporous nanoparticles and the 3D structure of the resulting composite. Itprevents the fragmentation of Fe3O4 particles induced by the formation of mesoporous structures and the restacking of rGO sheets generated by adjusting the layer spacing.

Tumor-targeted Gd-doped mesoporous Fe3O4 nanoparticles for T1/T2 MR imaging guided synergistic cancer therapy

In this study, a novel intelligent nanoplatform to integrate multiple imaging and therapeutic functions for targeted cancer theranostics. The nanoplatform, DOX@Gd-MFe3O4 NPs, was constructed Gd-doped mesoporous Fe3O4 nanoparticles following with the doxorubicin (DOX) loading in the mesopores of the NPs. The DOX@Gd-MFe3O4 NPs exhibited good properties in colloidal dispersity, photothermal conversion, NIR triggered drug release, and high T1/T2 relaxicity rate (r 1=9.64 mM−1s−1, r 2= 177.71 mM−1s−1). Benefiting from the high MR contrast, DOX@Gd-MFe3O4 NPs enabled simultaneous T1/T2 dual-modal MR imagining on 4T1 bearing mice in vivo and the MR contrast effect was further strengthened by external magnetic field. In addition, the DOX@Gd-MFe3O4 NPs revealed the strongest inhibition to the growth of 4T1 in vitro and in vivo under NIR irradiation and guidance of external magnetic field. Moreover, biosafety was also validated by in vitro and in vivo tests. Thus, the prepared DOX@Gd-MFe3O4 NPs would provide a promising intelligent nanoplatform for dual-modal MR imagining guided synergistic therapy in cancer theranostics.

Encapsulating highly crystallized mesoporous Fe3O4 in hollow N-doped carbon nanospheres for high-capacity long-life sodium-ion batteries

High capacity transition metal oxides have attracted much attention as potential sodium-ion batteries (SIBs) anodes. However, the fast capacity fading greatly limits their practical applications. In this study, highly crystallized mesoporous Fe3O4 nanoparticles encapsulated in the hollow nitrogen-doped carbon nanospheres (denoted as HCM-Fe3O4@void@N-C) have been synthesized and then explored as anode materials for SIBs. The resultant HCM-Fe3O4@void@N-C nanospheres possess a uniform particle size of ~ 180 nm with highly crystallized mesoporous Fe3O4 cores (~ 100 nm in diameter), a large surface area of ~ 250 m2 g−1 and a nitrogen-doped carbon shell (~ 7.6 wt%). Notably, a high discharge capacity of 372 mA h g−1 is obtained after the first five cycles at 160 mA g−1, which can gradually increase and be maintained at an ultrahigh specific capacity of 522 mA h g−1 even after 800 cycles. Besides, remarkable rate performance with a capacity of 196 mA h g−1 at a current density of 1200 mA g–1 and a high Coulombic efficiency (~ 100%) are obtained. Such good performance can be attributed to the unique yolk-shell nanostructure with a high crystallized mesoporous Fe3O4 core, a high conductive N-doped carbon shell, and a suitable void space, paving a new way to design and synthesize high-performance anode materials for SIBs.

Solvothermal Synthesis of Mesoporous Fe3O4 Nanoparticles in Mixed Solvent of Ethylene Glycol and Water: Structure and Magnetic Properties

Mesoporous Fe3O4 nanoparticles were synthesized by a solvothermal method, via a mixed solvent of ethylene glycol (EG) and deionized water, using iron chloride and urea as the precursors. The phase, morphology, and pore structure are investigated by the characterization of X-ray diffraction (XRD), transmission electron microscopy (TEM), and N2 isotherm adsorption–desorption. The results show that the amount of water in the mixed solvent plays vital role in controlling the size of Fe3O4 nanoparticles, specific surface area, and pore size. Additionally, solid Fe3O4 nanospheres were prepared using only EG as solvent, while α-Fe2O3 nanosized polyhedrals were obtained with only water as solvent. The mesoporous Fe3O4 nanoparticles show a ferromagnetic behavior, with saturation magnetizations (Ms) of 78–82 emu g− 1 and coercivities (Hc) ranging from 13–58 Oe. The α-Fe2O3 nanoparticles also exhibit a weak-ferrimagnetic character, with a remanent magnetization (Mr) of 0.24 emu g− 1, and Hc of 558 Oe.

A facile and stable colorimetric sensor based on three-dimensional graphene/mesoporous Fe3O4 nanohybrid for highly sensitive and selective detection of p-nitrophenol

To date, fabricating high sensitive, stable and facile sensing strategy for detection of nitrophenol still remains a challenge in practical applications. This article demonstrates for the first time a facile and stable colorimetric sensor based on three-dimensional graphene/mesoporous Fe3O4 (3D GF/m-Fe3O4) heterogeneous nanozyme. Using a simple hydrothermal procedure, mesoporous Fe3O4 nanoparticles were in situ synthesized on 3D GF. The 3D GF/m-Fe3O4 nanohybrid possesses high peroxidase mimicking activity due to the synergistic effect of 3D GF and m-Fe3O4. Based on the peroxidase-like activity and p-nitrophenol-mediated inhibition controllability, the nanohybrid was successfully adopted in the sensitive and selective sensing detections of p-nitrophenol (PNP) with a low detection limit of 45 nM. Moreover, 3D GF/m-Fe3O4 nanohybrid shows to be extremely robust, as it still retains its original response to PNP after being reused for 10 times. The method was applied to the determination of PNP in spiked lake water and gave good recoveries. With the merits of high sensitivity and selectivity, simplification, recyclability, and excellent stability, this sensing platform not only expands the application of 3D GF and Fe3O4, but also provides an alternative technique to construct robust nanozyme with multiple functionalities for various biological and environmental applications.

A multi-controlled drug delivery system based on magnetic mesoporous Fe3O4 nanopaticles and a phase change material for cancer thermo-chemotherapy

Herein a novel multi-controlled drug release system for doxorubicin (DOX) was developed, in which monodisperse mesoporous Fe3O4 nanoparticles were combined with a phase change material (PCM) and polyethylene glycol 2000 (PEG2000). It is found that the PCM/PEG/DOX mixture containing 20% PEG could be dissolved into water at 42 °C. The mesoporous Fe3O4 nanoparticles prepared by the solvothermal method had sizes of around 25 nm and exhibited a mesoporous microstructure. A simple solvent evaporation process was employed to load the PCM/PEG/DOX mixture on the mesoporous Fe3O4 nanoparticles completely. In the Fe3O4@PCM/PEG/DOX system, the pores of the Fe3O4 nanoparticles were observed to be filled with the mixture of PCM/PEG/DOX. The Fe3O4@PCM/PEG/DOX system showed a saturation magnetization value of 50.0 emu g−1, lower than 71.1 emu g−1 of the mesoporous Fe3O4 nanoparticles, but it was still high enough for magnetic targeting and hyperthermia application. The evaluation on drug release performance indicated that the Fe3O4@PCM/PEG/DOX system achieved nearly zero release of DOX in vitro in body temperature, while around 80% of DOX could be released within 1.5 h at the therapeutic threshold of 42 °C or under the NIR laser irradiation for about 4 h. And a very rapid release of DOX was achieved by this system when applying an alternating magnetic field. By comparing the systems with and without PEG2000, it is revealed that the presence of PEG2000 makes DOX easy to be released from 1-tetradecanol to water, owing to its functions of increasing the solubility of DOX in 1-tetradecanol as well as decreasing the surface tension between water and 1-tetradecanol. The novel drug release system shows great potential for the development of thermo-chemotherapy of cancer treatment.

Preparation of mesopourous Fe3O4 nanoparticle with template reagent: Tannic acid and the catalytic performance

We report a one-pot hydrothermal method for novel mesoporous Fe3O4 nanoparticles (NPs) preparation based on the reduction of ferric chloride with bifunctional agent: tannic acid (TA). TA acted both as template agent to obtain the mesoporous structure and functional agent to modify Fe3O4 NPs. The facile controlled process resulted in a relatively high surface area (99.5 m2 g−1) and good monodispersity with average diameter ∼200 nm of the synthetic nanoparticles. The high saturation magnetization (54.7 emu g−1) of the nanoparticles made it can be separated quickly from solution media via a magnet. The unique mesoporous structure of the Fe3O4 nanoparticles possessed high active site, and this was proved by studying the catalytic properties through Fenton catalytic degradation with hydrogen peroxide as a model reaction system. As a result, the tannic acid templated mesoporous Fe3O4 NPs (TA–Fe3O4 NPs) showed the very efficient catalytic properties for the degradation of methylene blue (MB) accelerated by the functionalization of TA.

Electrochemical determination of dopamine in the presence of uric acid using palladium-loaded mesoporous Fe3O4 nanoparticles

Amino-group functionalized mesoporous Fe3O4 nanoparticles were prepared by a simple solvothermal method. Palladium (Pd)-loaded amino-group functionalized mesoporous Fe3O4 nanoparticles (Pd@Fe3O4) were prepared with ethanol as the reductant. Pd@Fe3O4 modified the glassy carbon electrode (GCE) exhibited excellent electrochemical catalytic activities towards dopamine (DA) due to the synergetic effect between Pd and Fe3O4. Electrochemical behavior of Pd@Fe3O4/GCE towards DA was studied using square wave voltammetry and the selective determination of DA was carried out successfully at high concentration of uric acid. A wide concentration range (0.96–107μmol/L) and low detection limit (0.41μmol/L, S/N=3) for the determination of DA were obtained. The advantageous properties of this electrode for the DA determination lie in its excellent catalytic activity, selectivity and simplicity. The prepared sensor had been applied to the analysis of DA in human serum samples with satisfactory results.

Synthesis and properties of magnetic fluorescent bi-functional graphene oxide-based nanocomposites

A type of graphene oxide-based nanocomposite ((Fe3O4–ZnO QDs)@SiO2–GO nanocomposite) was synthesized via an amidation process by introducing mesoporous Fe3O4 nanoparticles and ZnO quantum dots onto the surface of GO. The structure characterization, optical properties, and magnetic properties of such nanocomposites were systematically studied by FT-IR and PL emission spectroscopy as well as AFM, VSM, TEM and SEM examination. The results show that the graphene oxide-based nanocomposite has high surface area, superparamagnetic properties and tunable fluorescence. Additionally, methylene blue was chosen as a model substance to investigate the loading capacity of this nanocomposite. The loading experiments indicate that such a nanocomposite has a loading capacity up to 1175.8 mg g−1, implying that this bi-functional graphene oxide-based nanocomposite is likely to find applications in some challenging fields such as drug carriers.

Synthesis and Enhanced Electromagnetic Wave Absorption Properties of Fe3O4@ZnO Mesoporous Spheres

ABSTRACTMesoporous Fe3O4 nanoparticles coated with ZnO nanocrystals were successfully synthesized by a simple solution method at low temperature. The transmission electron microscopy analysis indicates that the mesoporous Fe3O4 nanoparticles are monodispersed with a mean diameter of 160 nm and the thickness of ZnO layer is 15 nm approximately. The porosity of the products was further substantiated by the nitrogen (N2) sorption measurement. The N2 adsorption-desorption isotherm curve can be identified as type IV, which is a characteristic of mesopores. Electromagnetic (EM) wave absorption properties of the as-prepared Fe3O4@ZnO mesoporous spheres-wax composites were investigated at a room temperature in the frequency range of 0.5∼18 GHz. Interestingly, the Fe3O4@ZnO mesoporous spheres exhibit an enhanced EM wave absorption due to the mesoporous structure. The multiple absorbing mechanisms result from the interface polarization induced by the special core/shell and mesoporous structures as well as dipole polarization of both Fe3O4 and ZnO. The results demonstrate that the Fe3O4@ZnO mesoporous spheres are attractive candidates for a new kind of EM wave absorption materials with wide absorption frequency band.

Highly efficient removal of heavy metal ions by amine-functionalized mesoporous Fe3O4 nanoparticles

Amine-functionalized mesoporous Fe3O4 nanoparticles (AF-Fe3O4) were developed for the highly efficient removal of toxic heavy metal ions from water. AF-Fe3O4 were prepared by a new cost-effective and environmentally friendly procedure. The maximum amino-group grafted onto AF-Fe3O4 is 0.1790μg/mg by ninhydrin test. AF-Fe3O4 can be simply recovered from water with magnetic separations at low magnetic field within 1min. Each adsorption of 50mL 5mg/L of Pb(II), Cd(II), and Cu(II) onto 10mg of AF-Fe3O4 reached equilibrium within 120min at pH 7.0. It agreed well to the Langmuir adsorption model with maximum adsorption capacities for Pb(II), Cd(II), and Cu(II) from 369.0 to 523.6mg/g, which is larger than some other reports. The adsorption rates of Pb(II), Cd(II), and Cu(II) on AF-Fe3O4 fit pseudo-second order kinetic models (R2>0.99). Thermodynamic studies illustrated the adsorption process was endothermic and spontaneous. AF-Fe3O4 was able to remove over 98% of Cu(II), Cd(II) and Pb(II) in 50mL of solution containing 5mg/L metal ions at optimized conditions.

Anaerobic Biohydrogen Production by the Mixed Culture with Mesoporous Fe<sub>3</sub>O<sub>4</sub> Nanoparticles Activation

It was the first time to study the catalytic effect of mesoporous magnetic Fe3O4nanoparticles on the biohydrogen production. The mixed culture used in this study just suffered from an alkaline shock and lost its bioactivity of hydrogen production. We use mesoporous Fe3O4nanoparticles and ferrous ions as activators to recover the bioactivity of the mixed culture. The results indicate that the improvement of biohydrogen yield by mesoporous Fe3O4was obvious larger than that by ferrous ions. The maximum yield of cumulative hydrogen production was obtained at the mesoporous Fe3O4nanoparticles of 400 mg·L-1, which is 26% higher than that of the blank. The lag phases for hydrogen production in the tests added with mesoporous Fe3O4nanoparticles were decreased to 12 h, which are 50 h less than those of the corresponding ferrous ions and blank tests.