Graphene oxide-Fe3O4 Nanocomposites Research Articles

The Influence of Graphene Oxide-Fe3O4 Differently Conjugated with 10-Hydroxycampthotecin and a Rotating Magnetic Field on Adenocarcinoma Cells.

Nanoparticles (e.g., graphene oxide, graphene oxide-Fe3O4 nanocomposite or hexagonal boron nitride) loaded with anti-cancer drugs and targeted at cancerous cells allowed researchers to determine the most effective in vitro conditions for anticancer treatment. For this reason, the main propose of the present study was to determine the effect of graphene oxide (GO) with iron oxide (Fe3O4) nanoparticles (GO-Fe3O4) covalently (c-GO-Fe3O4-HCPT) and non-covalently (nc-GO-Fe3O4-HCPT) conjugated with hydroxycamptothecin (HCPT) in the presence of a rotating magnetic field (RMF) on relative cell viability using the MCF-7 breast cancer cell line. The obtained GO-Fe3O4 nanocomposites demonstrated the uniform coverage of the graphene flakes with the nanospheres, with the thickness of the flakes estimated as ca. 1.2 nm. The XRD pattern of GO-Fe3O4 indicates that the crystal structure of the magnetite remained stable during the functionalization with HCPT that was confirmed with FTIR spectra. After 24 h, approx. 49% and 34% of the anti-cancer drug was released from nc-GO-Fe3O4-HCPT and c-GO-Fe3O4-HCPT, respectively. The stronger bonds in the c-GO-Fe3O4-HCPT resulted in a slower release of a smaller drug amount from the nanocomposite. The combined impact of the novel nanocomposites and a rotating magnetic field on MCF-7 cells was revealed and the efficiency of this novel approach has been confirmed. However, MCF-7 cells were more significantly affected by nc-GO-Fe3O4-HCPT. In the present study, it was found that the concentration of nc-GO-Fe3O4-HCPT and a RMF has the highest statistically significant influence on MCF-7 cell viability. The obtained novel nanocomposites and rotating magnetic field were found to affect the MCF-7 cells in a dose-dependent manner. The presented results may have potential clinical applications, but still, more in-depth analyses need to be performed.

Tribological behavior of graphene oxide-Fe3O4 nanocomposites for additives in water-based lubricants

Graphene oxide-Fe3O4 (GO-Fe3O4) nanocomposites were synthesized via the solvothermal method and used as lubricant additives. The tribological tests and a series of characterization techniques were conducted to understand the lubrication mechanism of GO-Fe3O4 nanocomposite. The GO-Fe3O4 nanocomposites exhibited excellent tribological properties due to high dispersion stability in water. Friction results indicated that the GO-Fe3O4 can significantly improve the tribological properties and the friction coefficient and wear scar diameter had been reduced by 33.6% and 32.3% compared with base fluid, respectively. Raman results showed that the GO nanosheets formed a protective film on the contact interfaces, which facilitated shear, reduced the wear and inhibited the tribo-corrosion. The lubrication mechanism was attributed to the synergistic lubrication effect between the Fe3O4 nanospheres and the GO nanosheets.

Graphene oxide-Fe3O4 nanocomposite used as aniline adsorbent with a wide pH range

Graphene oxide-Fe3O4 nanocomposite used as aniline adsorbent with a wide pH range

Highly photocatalytic active r-GO/Fe3O4 nanocomposites development for enhanced photocatalysis application: A facile low-cost preparation and characterization

This research explores reduced graphene oxide-Fe3O4 nanocomposites synthesis, characterization, and it's ability to degrade methylene blue dye using sodium lamp as the visible white light source. The modified co-precipitation method was employed for the synthesis of the photocatalyst. The photocatalyst was further characterized by various characterization techniques. Moreover, photocatalytic activity was performed by varying performance conditions, and analyzed the results. It was found that photocatalyst has highly active performance at the working conditions of pH 12 with 50 mg catalyst for 10 ppm methylene blue dye solutions and produced 98.3% degradation of the dye within 80 min. It was also observed that minor positive performance was observed on varying temperature and catalyst concentration. The photocatalytic activity was found highly dependent on the pH of the solution and increased with an increase in pH. Additional studies were also performed by adding some amount of hydrogen peroxide in the solution without changing its pH. It was also noted that as the amount of hydrogen peroxide was increased in the solution, there was an increment in the degradation of the dye. A maximum of 98.8% degradation was recorded with the 9 ml addition of hydrogen peroxide-containing 25 mg catalyst, pH 8, and at 40 °C reaction temperature within 70 min of irradiation.

Fabrication of Graphene oxide-Fe3O4 nanocomposites for application in bone regeneration and treatment of leukemia

The current study illustrates the fabrication of Graphene oxide- Iron Oxide (GO-Fe3O4) nanocomposites by using a mechanical process called mechanochemical method, which is expected to produce particles with extreme heterogeneity. The characterization of fabricated nanocomposites was done by using techniques like Transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Raman spectroscopy and X-ray diffraction (XRD) analysis. Investigation of osteogenic differentiation effects in the mesenchyme cells derived from the bone marrow (BMSCs) of rat and corresponding mechanisms were carried out for the 1st time by using the prepared composite. GO-Fe3O4 could noticeably increase BMSCs osteogenic differentiation other than being biocompatible at lower concentrations. Concentration relayed characteristics were shown in GO-Fe3O4 treated BMSCs bone development differentiation as well as in their cellular behavior. Additionally, GO-Fe3O4 displayed different effects on cell viability through dose-dependent selective killing of cancer cells without affecting normal cells in the MTT assay. Reactive oxygen species (ROS) generation revealed the dose-dependent cytotoxicity of GO-Fe3O4 towards K562 cells. The GO-Fe3O4 caused apoptosis was identified using propidium iodide and acridine orange double staining. Further, the prepared material can have prospective for future bone regeneration applications and in treatment of leukemia.

Covalent immobilization of laccase on Fe3O4–graphene oxide nanocomposite for biodegradation of phenolic compounds

Covalent immobilization of laccase on Fe3O4–graphene oxide nanocomposite for biodegradation of phenolic compounds

Synthesis of covalently bonded reduced graphene oxide-Fe3O4 nanocomposites for efficient electromagnetic wave absorption

High-performance electromagnetic (EM) wave absorbers, covalently bonded reduced graphene oxide-Fe3O4 nanocomposites (rGO-Fe3O4), are synthesized via hydrothermal reaction, amidation reaction and reduction process. The microstructure, surface element composition and morphology of rGO-Fe3O4 nanocomposites are characterized and corresponding EM wave absorption properties are analyzed in great detail. It demonstrates that Fe3O4 nanoparticles are successfully covalently grafted onto graphene by amide bonds. When the mass ratio of rGO and Fe3O4 is 2:1 (sample S2), the absorber exhibits the excellent EM wave absorption performance that the maximum reflection loss (RL) reaches up to -48.6 dB at 14.4 GHz, while the effective absorption bandwidth (RL<-10 dB) is 6.32 GHz (11.68–18.0 GHz) with a matching thickness of 2.1 mm. Furthermore, radar cross section (RCS) simulation calculation is also adopted to evaluate the ability of absorbers to scatter EM waves, which proves again that the absorption performance of absorber S2 is optimal. The outstanding EM wave absorption performance is attributed to the synergistic effect between dielectric and magnetic loss, good attenuation ability and excellent impedance matching. Moreover, covalent bonds considered to be carrier channels can facilitate electron migration, adjust EM parameters and then enhance EM wave absorption performance. This work provides a possible method for preparing efficient EM wave absorbers.

High-performance cement containing nanosized Fe3O4–decorated graphene oxide

The current study presents a new idea for reinforcing the cement and its realization. The idea includes the increase of the surface roughness of the graphene oxide (GO) sheets through their decoration by nanoparticles, which enhances the interaction between filler and cement matrix. To reinforce the cement, the GO–Fe3O4 hybrid nanocomposite were prepared by electrostatic attraction approach. The hybrid filler was added to the cement paste with different graphene content. The performance of the composite materials were evaluated in different aspects. It was revealed that the sample containing 0.25 wt% Fe3O4 and 0.05 wt% GO (FG5) exhibited the best physical and mechanical behaviors. The FG5 sample showed an increase in compressive, flexural, and tensile strengths by 53, 94, and 86%, respectively, in comparison with those of the plain cement sample after 28 days of hydration. In addition, 148% growth for the toughness and 31% reduction for the total porosity of this sample compared to those of the neat cement sample were obtained. The XRD and morphological results for the cement containing GO–Fe3O4 nanocomposite indicated the formation of a denser, more integrated structure.

Magnetic Fe3O4-graphene oxide nanocomposite – synthesis and practical application for the heterogeneous photo-Fenton degradation of different dyes in water

ABSTRACT Characterization and test a magnetic graphene oxide (GO) nanocomposite (Fe3O4-GO) in the photo-degradation of Methylene Blue (MB), Reactive Black 5 (RB), and Acid Blue 80 (AB) dyes were investigated in this work. Measurements indicated that GO was decorated by Fe3O4. Kinetic tests showed that the process was more efficient in degrade MB – %Degradation MB>RB>AB; also in the regeneration and reuse of the photocatalyst. Regarding the phytotoxicity, all seeds germinated, although a decrease in the root length after the photodegradation was observed. In overall, Fe3O4-GO seems to be a promissory photocatalyst for the degradation of different textile dyes.

Electrochemical Determination of Levodopa on Carbon Paste Electrode Modified with Salmon Sperm DNA and Reduced Graphene Oxide–Fe3O4 Nanocomposite

In this work, an electrochemical label-free DNA biosensor was developed for determination of levodopa (LD). The biosensor was constructed using reduced graphene oxide decorated with Fe3O4 magnetic nanoparticles (rGO–Fe3O4) on a carbon paste electrode (CPE) and double-stranded deoxyribonucleic acid (DNA) (DNA/rGO–Fe3O4-CPE). The application was related to the molecular interaction between LD and DNA. Thus, the voltammetric behavior of LD at the surface of DNA/rGO–Fe3O4-CPE was studied using differential pulse voltammetry (DPV) where the oxidation peak current of LD was measured as an analytical signal. A considerable increase was observed in the oxidation signal of LD at the DNA-coated electrode compared to the DNA-free electrode, indicating the pre-concentration of LD due to the interaction with the surface-confined DNA layer. Scanning electron microscopy, energy dispersive X-ray and Fourier transform infrared spectroscopy confirmed the structure of the synthesized nanocomposites (electrode composition). Electrochemical studies revealed that modification of the electrode significantly increases the oxidation peak currents of LD. Under the optimum conditions, the calibration curve was linear in the range of 0.5–600 nM with a detection limit of 0.11 nM. The relative standard deviation for 200.0 nM was 4.07% (n = 5). The developed biosensor was successfully applied to the analysis of LD in human serum and urine sample.

An enzymatic performance for a new swift magnetically detachable bio-conjugate of Candida rugosa lipase with modified Fe3O4–graphene oxide nanocomposite

The high stability, reusability, half-life, and catalytic activity, accompanied by facile separation from the reaction products, are essential for fulfilling the promise of biocatalysts for different applications in analytical and industrial processes. Here, the Candida rugosa lipase (CRL) immobilization on a new chemically modified, magnetically coated graphene oxide nanosheets is presented. The synthesis, modification, and CRL immobilization operations are monitored and verified through XRD, VSM, FT-IR, TEM, SEM, EDS, UV−Vis, and AFM techniques. The appraisal of operational parameters reveals the high-grade reusability, high pH, thermal, and storage stability of the synthesized swift magnetically detachable biocatalyst. The molecular interpretation of this catalytic performance represents by enzyme–enzyme and enzyme–product interactions. This unique magnetic bio-conjugate with outstanding performance recommends for analytical and industrial applications in a wide range of temperature and pH.

Synthesis of Graphene Oxide-Fe3O4 Based Nanocomposites Using the Mechanochemical Method and in Vitro Magnetic Hyperthermia.

The study presented in this work consists of two parts: The first part is the synthesis of Graphene oxide-Fe3O4 nanocomposites by a mechanochemical method which, is a mechanical process that is likely to yield extremely heterogeneous particles. The second part includes a study on the efficacy of these Graphene oxide-Fe3O4 nanocomposites to kill cancerous cells. Iron powder, ball milled along with graphene oxide in a toluene medium, underwent a controlled oxidation process. Different phases of GO-Fe3O4 nanocomposites were obtained based on the composition used for milling. As synthesized nanocomposites were characterized by x-ray diffraction (XRD), alternating magnetic field (AFM), Raman spectroscopy, and a vibrating sample magnetometer (VSM). Additionally, the magnetic properties required to obtain high SAR values (Specific Absorption Rate-Power absorbed per unit mass of the magnetic nanocomposite in the presence of an applied magnetic field) for the composite were optimized by varying the milling time. Nanocomposites milled for different extents of time have shown differential behavior for magneto thermic heating. The magnetic composites synthesized by the ball milled method were able to retain the functional groups of graphene oxide. The efficacy of the magnetic nanocomposites for killing of cancerous cells is studied in vitro using HeLa cells in the presence of an AC (Alternating Current) magnetic field. The morphology of the HeLa cells subjected to 10 min of AC magnetic field changed considerably, indicating the death of the cells.

The properties of the sonochemically functionalized nonsteroidal anti-inflammatory drug ketorolac in an Fe3O4–graphene oxide nanocomposite

A feasible sonochemical method is developed for the complexation of nonsteroidal anti-inflammatory drug ketorolac with the Fe3O4–graphene oxide nanocomposite.

Fe3O4-Graphene oxide nanocomposite: Synthesis of 5-sulfanyl tetrazole derivatives of alkyls, indoles, and pyrroles

In this work, the use of Fe3O4/geraphene oxide nanocomposite as an efficient catalyst for the synthesis of 5-sulfanyltetrazole derivatives of indoles, pyrroles, and 5-alkyl sulfanyltetrazoles is described. These compounds are readily obtained by the reaction of the starting heterocycles indoles, N-aryl pyrroles, alkyl thiocyanates, and trimethylsilyl azide in good to excellent yields. Moreover, Fe3O4/GO nanocomposite could be easily separated from the reaction mixtures by an external permanent magnet and reused at least six times continuously without significant reduction in the product yield and its catalytic activity.

Preparation and Characterization of Reduced Graphene Oxide–Fe3O4 Nanocomposites in Polyacrylamide

A hydrogel nanocomposite composed of reduced graphene oxide (RGO), iron oxide (Fe3O4) nanoparticles, and polyacrylamide (PAM) was prepared using radical polymerization. Different percentages of RGO, Fe3O4, and PAM were used to prepare the nanocomposite. Fourier transform infrared spectroscopy (FT-IR) results confirmed the formation of the nanocomposite’s chemical structure. X-ray power diffraction (XRD) patterns revealed the principal peak’s 2θ value to be 77.3° with the size of the nanocomposite particles estimated at 77 nm. Results indicated that the electrochemical capacity of the nanocomposites was controlled by the weight percentage of RGO. Increases to the potential scan rate reduced porosity and surface area, thereby decreasing the electrochemical capacity of the nanocomposites. Moreover, increasing the percentage of Fe3O4 nanoparticles in the nanocomposites improved their magnetic characteristics and thermal properties. The latter also improved when the RGO percentage increased.

Design of three-dimensional macroporous reduced graphene oxide–Fe3O4 nanocomposites for the removal of Cr(VI) from wastewater

Three-dimensional macroporous reduced graphene oxide–Fe3O4 nanocomposites (3D macroporous rGO–Fe3O4 nanocomposites) were synthesized through electrostatic self-assembly method. The morphology and structure characteristics of 3D macroporous rGO–Fe3O4 nanocomposites were studied in detail. Then 3D macroporous rGO–Fe3O4 nanocomposites were used as adsorbents for the removal of Cr(VI) from wastewater. The effects of contact time and solution pH on the adsorption properties of 3D macroporous rGO–Fe3O4 nanocomposites were also investigated. Due to the hierarchical porous structure, high surface area and large pore volume, 3D macroporous rGO–Fe3O4 nanocomposite adsorbents exhibited excellent adsorption capability and rapid adsorption rates for Cr(VI) from aqueous solution. The kinetic and isothermal studies suggested that the adsorption process could be best described by pseudo-second-order kinetic model and Langmuir isotherm model, respectively. Moreover, the adsorbents could be separated easily by an external magnetic field for reusability, demonstrating great potential for the treatment of wastewater containing Cr(VI) during practical applications.

Magnetic solid-phase extraction for the analysis of bisphenol A, naproxen and triclosan in wastewater samples.

Magnetic Fe3O4 graphene oxide nanocomposite was synthesized by chemical coprecipitation method and characterized by scanning electron microscopy, Fourier transform infrared spectra and X-ray diffraction. A simple, rapid, convenient and environmentally friendly method was developed for separation and pre-concentration of trace amounts of bisphenol A, naproxen and triclosan in wastewater samples by high performance liquid chromatography with magnetic Fe3O4 graphene oxide nanocomposite as the adsorbent for magnetic solid-phase extraction. Various parameters possibly influencing the extraction performance such as amount of the adsorbent, extraction time, sample pH and elution conditions were optimized. Under the optimal working conditions, the developed method showed good linearity (R > 0.9997) in the range of 1-200 μg/L, and the limits of detection are between 0.5 and 0.8 μg/L. The enrichment factors are in the range of 81-89. The repeatability of the method, expressed as relative standard deviation, is 3.36-4.26%.

Preparation and characterization of reduced graphene oxide/Fe3O4 nanocomposite by a facile in-situ deposition method for glucose biosensor applications

In this work, the reduced graphene oxide-Fe3O4 nanocomposite (rGO/Fe3O4) was prepared by a facile in-situ deposition of Fe3O4 nanoparticles on graphene sheets. The fact that graphene oxide (GO) was completely reduced to graphene by Fe2+ was evidenced by X-ray diffractometer, ultraviolet visible spectrophotometer, Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy. The results showed Fe3O4 nanoparticles were generated uniformly and bonded on the surface of rGO with a particle size of about 50 nm. In addition, the rGO/Fe3O4 nanocomposite showed a good conductivity and was considered as a high volume-surface ratio matrix for the immobilization of glucose oxidase (GOx) on a glassy carbon electrode (GCE). The fabricated rGO/Fe3O4/GOx/GCE exhibited a fast electron transfer and good electrocatalytic activity due to the good electrochemical properties of the rGO/Fe3O4 nanocomposite. These results demonstrated that the rGO/Fe3O4 nanocomposite prepared by in-situ deposition could be applied to high performance biosensor for glucose detection.

Immobilization of Candida rugosa lipase onto graphene oxide Fe3O4 nanocomposite: Characterization and application for biodiesel production

The purpose of this work is to develop a magnetically recyclable immobilized lipase for biodiesel production to meet the need of green and clean production. To achieve this, magnetic Fe3O4 nanoparticles were encapsulated in graphene oxides (GO), and then employed as a magnetic carrier for the immobilization of lipase from Candida rugosa via the interfacial activation of enzyme on hydrophobic surfaces. By using this immobilization strategy, the activity recovery of 64.9% and enzyme immobilization efficiency of 85.5% could be achieved. The as-prepared graphene oxide Fe3O4 nanocomposite (MGO) and immobilized lipase microsphere were fully characterized by means of enzyme activity assays, transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, vibrating-sample magnetometer (VSM) and nitrogen adsorption–desorption techniques. It was shown that the Fe3O4 nanoparticles were successfully encapsulated into the GO, and moreover the lipase was tethered on the magnetic support. The immobilized lipase could efficiently catalyze the transesterification of soybean oil with methanol for the production of biodiesel. With this magnetic biocatalyst, the biodiesel yield of 92.8% could be obtained at a temperature of 40 °C by three-step addition of methanol in a shaking water bath. The immobilized lipase could be easily recovered by using an external magnetic field, allowing for recycling of the biocatalyst five times without significant loss of its activity.

Superparamagnetic graphene oxide-based dispersive-solid phase extraction for preconcentration and determination of tamsulosin hydrochloride in human plasma by high performance liquid chromatography-ultraviolet detection

In the present study, superparamagnetic graphene oxide-Fe3O4 nanocomposites were successfully prepared by a modified impregnation method (MGOmi) and their application as a sorbent in the magnetic-dispersive solid phase extraction (M-dSPE) mode to the preconcentration and determination of tamsulosin hydrochloride (TMS) in human plasma was investigated by coupling with high performance liquid chromatography-ultraviolet detection (HPLC-UV). The structure, morphology and magnetic properties of the prepared nanocomposites were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and vibrating sample magnetometry (VSM). Some factors affecting the extraction efficiency, including the pH value, amount of sorbent, extraction time, elution solvent and its volume, and desorption time were studied and optimized. Magnetic nanocomposites plasma extraction of TMS following HPLC analyses showed a linear calibration curve in the range of 0.5–50.0ngmL−1 with an acceptable correlation coefficient (R2=0.9988). The method was sensitive, with a low limit of detection (0.17ngmL−1) and quantification (0.48ngmL−1). Inter- and intra-day precision expressed as relative standard deviation (n=3) and the preconcentration factor, were found to be 5.6–7.2%, 2.9–4.2% and 10, respectively. Good recoveries (98.1–101.4%) with low relative standard deviations (4.2–5.0%) indicated that the matrices under consideration do not significantly affect the extraction process. Due to its high precision and accuracy, the developed method may be a HPLC-UV alternative with M-dSPE for bioequivalence analysis of TMS in human plasma.