Magnetic Graphene Oxide Nanoparticles Research Articles

Magnetic curcumin–copper graphene oxide as facile and recyclable heterogeneous nanocatalyst for preparation of polyhydroquinolines and sulfoxides

In this research project, a versatile procedure has been designed for the preparation of supported copper@curcumin on magnetic graphene oxide nanoparticles (GO@Fe3O4@Cur–Cu). The structure of prepared nanocatalyst was characterized by several techniques including; Fourier transform infrared, powder X-ray diffraction, thermal gravimetric analysis, energy dispersive X-ray analysis, inductively coupled plasma optical emission spectroscopy, vibrating sample magnetometer, transmission electron microscopy, and scanning electron microscopy analyses. The catalytic properties of GO@Fe3O4@Cur–Cu were examined for the efficient synthesis of polyhydroquinolines as well as the preparation of sulfoxides through selective oxidation of sulfides in the presence of hydrogen peroxide.

Preparation and Characterization of Nanohybrids Made of Graphene Oxide as Super Adsorbents

Adsorption is considered one of the best methods for the removal of heavy metal ions from an aqueous solution. However, the synthesis of adsorbents with desired selectivity and performance remains a key challenge in the battle of water decontamination. Recently, carbon-based and metal-oxide based nanomaterials have emerged as promising candidates for the adsorption of heavy metals due to their high specific surface area, high aspect ratio, and concentrated pore size distribution. Here, in this work five adsorbents ie. Graphene Oxide (GO), Magnetic Graphene Oxide (MGO), Titanium Dioxide (TiO2), and their composites GO-TiO2 and MGO-TiO2 were synthesized. The prepared samples were characterized via high-resolution imaging, BET-N2 adsorption-desorption analysis, and spectroscopic techniques. TEM results revealed the nanoscale structures of the synthesized nanomaterials. The approximate sizes of MGO and TiO2 nanoparticles found under TEM studies were about 24.58 and 35.51 nm respectively. The presence of desired functional groups was very well deciphered by FT-IR spectroscopy. Results of N2 adsorption-desorption studies revealed that the prepared GO was macro-porous while all other samples were mesoporous. MGO was found to have the highest BET surface area of about 108.375 m2/g. These results indicate that the prepared nanomaterials may serve the purpose of effectively adsorbing the heavy metal ions from an aqueous solution.

Removal of erythromycin antibiotic from the aqueous media using magnetic graphene oxide nanoparticles

Removal of erythromycin antibiotic from the aqueous media using magnetic graphene oxide nanoparticles

Aptamer decorated magnetic graphene oxide nanoparticles for effective capture of exosomes

Exosomes secreted by most cells possese many biological functions and arouse great interest in biomedical research. However, the effective and convenient methods for the capture of exosomes from clinical samples or cultured cells is still scarce. In this work, we developed novel magnetic graphene oxide nanoparticles (MGONs) for the efficient capture of exosomes, in which Fe3O4@SiO2 magnetic nanoparticles (NPs) were decorated with GO through dopamine. CD63 aptamers were attached to the surface of MGONs, which could recognize and bound to CD63 on the exosome membrane. The number of exosomes adsorbed onto the MGONs surface was 1.5 times that attached to the Fe3O4@SiO2 surface. The capture rate of exosomes reached as high as 89.4% within 15 min at room temperature. Moreover, exosomes can be effectively enriched and isolated under external magnetic field and the capture process did not affect their morphological structure and biological functions. Through hybridizing with a FAM-labelled single-stranded DNA probe, the concentration of captured exosomes could also be recorded by measuring the fluorescence intensity, and the limit of detection of this system reached 2.4 × 107 particles/ml. These aptamer-decorated MGONs also showed potential in high-effieient capture of exosomes using cancer patients samples, which demonstrated that the resultant MGONs had significant practical values in early disease diagnosis and the related clinical applications.

Solvent-free mechanochemical preparation of graphene oxide-Fe3 O4 and its application in magnetic dispersive solid-phase extraction of illegal dyes in food samples.

A simple, green, and efficient mechanochemical approach was developed herein to prepare tunable magnetic graphene oxide nanoparticles. The obtained nanoparticles were successfully used as adsorbents in a magnetic dispersive solid-phase extraction method to extract three cationic dyes (i.e., thioflavine T, auramine-O, and basic orange 2) found in food samples. Our proposed approach also utilized high-performance liquid chromatography with ultraviolet detection. Several key variables affecting the extraction recovery were investigated. These included the sample pH, amount of extractant, extraction time, sample volume, elution solvent type and volume, and the stability and reusability of the magnetic graphene oxide nanoparticles. Under optimized conditions, the calibration curve was linear at a concentration range of 0.005-1.0 μg/mL with a correlation coefficient of 0.9992-0.9996. Moreover, the limits of detection were determined at 0.97-1.35 μg/mL. The extraction mechanism was investigated via ultraviolet-visible spectrophotometry and zeta-potential analyses. The developed method was used to analyze the above-mentioned cationic dyes in bean products and yellow fish samples. Notably, satisfactory spiked recoveries ranging from 90.7 to 104.9% were achieved.

Facile fabrication of magnetic chitosan hydrogel beads and modified by interfacial polymerization method and study of adsorption of cationic/anionic dyes from aqueous solution

Dyes are a new type of environmental and water pollution which has caused global concern. Many researchers have been done in order to remove dyes from wastewater based on adsorption. This project describes the preparation of magnetic chitosan hydrogel beads based on chitosan biopolymer, magnetic graphene oxide nanoparticles (GO/Fe3O4), and isophthaloyl chloride for removal of cationic and anionic dyes from aqueous solution. Chitosan hydrogel beads were prepared in the presence of GO/Fe3O4 nanoparticles. GO/Fe3O4 nanoparticles were prepared by the in-situ co-precipitation method. Afterward, amine groups in chitosan/GO/Fe3O4 hydrogel beads reacted with acyl chloride (in isophthaloyl chloride) via interfacial polymerization technique to modify surface of hydrogel beads. The results showed that the kinetic data and adsorption isotherm were best-correlated to the pseudo-second-order model and Langmuir model, respectively. The maximum adsorption capacities of cationic MB and anionic EBT were 289 and 292 mg/g, respectively. Moreover, the mechanism for the adsorption was studied by the fitting of isotherm data by the Dubinin-Radushkevich model showed that happened by the physio-sorption mechanism. The thermodynamic data indicated that the adsorption process was spontaneous, favorable and endothermic.

Fe3O4/Graphene Oxide Composite for Adsorption of Methylene Blue and Methyl Orange in Water Treatment

Magnetic nanoparticle–graphene oxide (Fe3O4/GO) nanocomposite was synthesized for two reasons: this is a good adsorbent for the adsorption of methylene blue (MB) and methyl orange (MO) from aqueous solutions; and due to its magnetic properties, it can be easily separated from aqueous solution using a magnet. This adsorbent was characterized by FTIR, SEM, and XRD techniques. Several parameters such as pH of the solution, the amount of adsorbent, adsorption time, type and volume of elution solvent, and desorption time were optimized to improve the adsorption recovery. The maximum adsorption recovery was obtained at the optimized solution pH of 6.0 using 10.0 mg adsorbent for 10.0 min. According to the Langmuir isotherm, the maximum adsorption capacity was 666.7 and 714.3 mg/g for MB and MO, respectively. The limit of detection (LOD) was also determined as 0.9 and 1.0 μg/L for MB and MO, respectively. Owing to the good repeatability and reproducibility of this adsorbent, it can be considered as a promising candidate for water treatment purposes. Consequently, this adsorbent was used for the adsorption of MB and MO from natural water samples.

Quantitative determination of trace phenazopyridine in human urine samples by hyphenation of dispersive solid-phase extraction and liquid-phase microextraction followed by gas chromatography/mass spectrometry analysis.

Magnetic dispersive solid-phase extraction followed by dispersive liquid-liquid microextraction coupled with gas chromatography/mass spectrometry was applied for the quantitative analysis of phenazopyridine in urinary samples. Magnetic dispersive solid-phase extraction was carried out using magnetic graphene oxide nanoparticles modified by poly(thiophene-pyrrole) copolymer. The eluting solvent of this step was used as the disperser solvent for the dispersive liquid-liquid microextraction procedure. To reach the maximum efficiency of the method, effective parameters including sorbent amount, adsorption time, type and volume of disperser and extraction solvents, pH of the sample solution, and ionic strength as well as desorption time, and approach were optimized, separately. Characterization of the synthesized sorbent was studied by utilizing infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analysis. Calibration curve was linear in the range of 0.5-250ng/mL (R2 =0.9988) with limits of detection and quantification of 0.1 and 0.5ng/mL, respectively. Intra- and interday precisions (RSD%, n=3) of the method were in the range of 4.6-5.4% and 4.0-5.5%, respectively, at three different concentration levels. Under the optimal condition, this method was successfully applied for the determination of phenazopyridine in human urine samples. The relative recoveries were obtained in the range of 85.0-89.0%.

High efficient removal and mineralization of Cr(VI) from water by functionalized magnetic fungus nanocomposites

A hydroxyl-functionalized magnetic fungus nanocomposite (MFH@GO) was prepared by a simple one-pot method for the removal of Cr(VI) from wastewater. The adsorption behavior of MFH@GO to Cr(VI) in wastewater was discussed in detail. At pH of 5.0 and temperature of 323.15 K, MFH@GO had higher adsorption capacity to Cr(VI) (58.4 mg/g) than the unmodified fungus and GO. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry and differential thermal analysis (TG-DTA), scanning electron microscopy and energy dispersive X-Ray spectroscopy (SEM-EDX) were employed to determine the characteristics of MFH@GO. Results showed that magnetic graphene oxide nanoparticles significantly enhanced the physiochemical properties of the fungi. In addition, the adsorption mechanisms analyses show that Cr(VI) could be reduced and mineralized into ferric chromate in residues. These results suggested that MFH@GO could be used as an promising and alternative biosorbent for removal of Cr(VI) from industrial wastewater.

The fabrication of dendrimeric phenylboronic acid-functionalized magnetic graphene oxide nanoparticles with excellent adsorption performance for the separation and purification of horseradish peroxidase

A dendrimeric phenylboronic acid-affinitive magnetic graphene oxide nanoparticle was synthesized and used to separate and purify HRP.

Self-Assembled Magnetic Nanoparticle–Graphene Oxide Nanotag for Optomagnetic Detection of DNA

In this work, a two-dimensional self-assembled magnetic nanoparticle–graphene oxide (MNP-GO) nanocomposite is reported for the detection of DNA. Single-stranded DNA (ssDNA) coils, generated through a rolling circle amplification (RCA) reaction triggered by the hybridization of target oligos and padlock probes, have a strong interaction with MNP-GO nanotags through several mechanisms including π–π stacking, hydrogen bonding, van der Waals, electrostatic, and hydrophobic interactions. This interaction leads to a hydrodynamic size increase or aggregation of MNP-GO nanotags, which can be detected by a simple optomagnetic setup. Due to the high shape anisotropy, MNP-GO nanotags provide stronger optomagnetic signal than individual MNPs. Moreover, the avoidance of DNA probes (i.e., short ssDNA sequences as the biosensing receptor) provides easier material preparation and lower measurement cost. From real-time measurements of interactions between MNP-GO and RCA products amplified from a highly conserved Escherich...

Mo (CO)6‐assisted Pd‐supported magnetic graphene oxide‐catalyzed carbonylation‐cyclization as an efficient way for the synthesis of 4(3H)‐quinazolinones

In this paper, a novel catalyst is introduced based on the immobilization of palladium on modified magnetic graphene oxide nanoparticles. The catalyst is characterized by several methods, including transmission electron microscopy, scanning electron microscopy, X‐ray fluorescence, vibrating‐sample magnetometer, Fourier transform‐infrared and dynamic light scattering (DLS) analysis. The activity of the catalyst was investigated in the synthesis of 4(3H)‐quinazolinones via Pd‐catalyzed carbonylation‐cyclization of N‐(2‐bromoaryl) benzimidamides by Mo (CO)6. The Mo (CO)6 is used as a carbon monoxide source for performing the reaction under mild conditions. The catalyst showed good reusability, and no change in activity was observed after 10 cycles of recovery.

Synergistic effects of Radiofrequency Hyperthermia temperature rate with magnetic Graphene oxide nanoparticles drug targeting on CT26 colon cancer cell line

Introduction: Graphene oxide (GO) sheets are carbon-networking nanomaterials offering excellent potential for drug delivery platforms due to hydrophobic interactions and high drug-loading efficiency. Superparamagnetic iron oxide nanoparticles can be used in certain applications such as cell labeling, drug delivery, targeting, magnetic resonance imaging and hyperthermia. Due to the larger surface to volume ratio for unmodified iron oxide nanoparticles, they usually possess high surface energy leading to particle aggregation. The magnetic nanoparticles could induce heat energy in an alternating magnetic field (AMF). The absorption of radiofrequency energy by biological tissue results in higher tissue temperatures as a function of time, which eventually causes cell death due to hyperthermia. Mensuration of the temperatures inside the tumors and in normal tissues within AMF demonstrated that this treatment could induce tumor-specific hyperthermia. Materials and Methods: CT26 colon cancer cell line was cultured in vitro as a monolayer. The monolayer culture was treated with of 5-FU, 5-FU- MGO nanoparticles, and MGO nanoparticles for 24 hours. then the flasks were located at the centre of the RF coil where the alternative magnetic field strength had reached its maximum value (40 kA/m) and was exposed to the AMF (forward power, 70 W), for 12 min (43°C) without MGO nanoparticles and 4 min (43°C) with MGO nanoparticles. During the AMF exposure, the temperature increase was monitored using a T-type thermocouple (copperconstantan, 0.1 mm diameter) linked to a digital thermometer (Lutron thermometer TM-917, Taiwan) every 1 min for 15 min with ± 0.1°C accuracy. Results: Increase in the temperature was measured. The results revealed that the temperature increase of the culture depends on the nanoparticles concentrations. The results also indicated that the temperature of cells exposed to AMF (13.56 MHz) at a forward power of 70 W reached to 43°C after 12 min, whereas the combination of accumulated 50 μg/ml 5-FU- MGO nanoparticles and RF hyperthermia was 3 min and for 25 and 5 μg/ml, it was calculated as 4 and 9 min, respectively. The significant difference was observed between the 5-FU, 5- FU- MGO nanoparticles, and MGO nanoparticles in RF hyperthermia at power of 70 W (P < 0.05). This suggests that MGO nanoparticles act as effective thermal agents in AMF hyperthermia. Conclusion: On the basis of this study is According to the temperature-time curves at different intensities, the rate of temperature rise was very sharp during the first few minutes of AMF exposure; however, it then reached a near equilibrium because cell heat transfer parameters (conduction and convection) started to perform, The radiofrequency heats cells with a steep gradient pending the initial stage of exposure.

Magnetic solid phase extraction of sulfonamides based on carboxylated magnetic graphene oxide nanoparticles in environmental waters

A magnetic nano-adsorbent material was prepared by functionalizing carboxylic group onto the granule surface of magnetic graphene oxide nanoparticles (CMGO), using in-situ co-precipitating method. The surface morphology was characterized by SEM and TEM. The CMGO was selected as the adsorbent for the magnetic solid phase extraction (MSPE) of sulfonamides (SAs) from environmental water samples, and the eluted analytes were determined by ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A series of experimental parameters were optimized to improve the extraction efficiency such as amount of CMGO, extraction time, pH, ionic strength of the sample solution and desorption conditions. When the pH of water sample was 4.00, the extraction recoveries (ERs) for SAs were over 82.0% with 15.0 mg CMGO adsorption for 20 min. Under the optimized extraction conditions, linear range was obtained with coefficients of determination (R2)≥0.9983. The limits of detection for this proposed method were in the range of 0.49–1.59 ng/L, and the enrichment factors were 1320-1702 for eight SAs. The newly developed method was successfully applied to the analysis of trace SAs in real-world water samples, which provided satisfactory ERs in the range of 82.0–106.2% with RSDs less than 7.2%. Overall, it shows a great potential for the concentration of trace amine organic pollutions in complex matrices.

Preconcentration of Pd ion in novel modified magnetic graphene oxide nanoparticles in different samples and its determination by ETAAS

Since Magnetic Graphene Oxide (MGO) nanoparticles are good adsorbents of metal ions, we tried a simple and fast process to produce them. Using the chemical co-precipitation of Co3O4 magnetic nanoparticles on GO nano-platelets, MGO was prepared. The different properties of the synthesized nanocomposite were investigated by using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD), and a Vibrating Sample Magnetometer (VSM). The results were indicative of MGO successful preparation and anchoring of Co3O4 nanoparticles on MGO nanosheets. To remove Pd (II) ions from aqueous solutions, MGO was applied as a sorbent. The effects of different parameters like pH, acid concentration, adsorbent type and amount, and contact and ultrasonication times were optimized under optimum conditions. A limit of 1.81 ng L−1 was obtained for detection. The linear range for palladium was between 0.01 and 0.50 ng mL-1 . ±3.1% was the relative SD for the 8 replicates (0.10 ng mL-1) of Pd (II) based on this approach. As a result, this method was believed to provide a wide application in the water purification process.

Rapamycin loaded magnetic graphene oxide nanoparticles as tumor-targeted drug delivery system: synthesis and in vitro characterization

The current study was designed to develop and optimize lazaroid loaded nano-structured lipid carriers (LAZ-NLCs) using design of experiment approach for enhancing lazaroid brain exposure. Response surface plots were used to determine the effects of independent variables (amount of PEGylating agent and liquid lipid) on dependent variables (particle size, zeta potential and encapsulation efficiency), while numerical optimization was used for optimizing LAZ-NLCs composition. The optimal LAZ-NLCs were spherical in shape with measured size of 172.3 ± 3.54 nm, surface charge of −4.54 ± 0.87 mV and encapsulation efficiency of 85.01 ± 2.60%. The optimal LAZ-NLCs were also evaluated for hemolytic potential, storage stability and solid-state properties. The plasma pharmacokinetics along with brain and hepatic distributions of control lazaroid citrate solution and optimal LAZ-NLCs formulation were evaluated in Sprague-Dawley rats after the single bolus intravenous administration. The optimized LAZ-NLCs and the control lazaroid citrate solution had similar plasma pharmacokinetic profiles; however, differential organ bio-distributions were observed. The lazaroid exposure in brain was enhanced by two times with a decreased liver exposure by half for the NLCs group compared to the solution group.

Efficient removal and trace determination of chlorophenols from water using mixed hemi-/ad-micelle ionic liquid-coated magnetic graphene oxide and the adsorption mechanism

Solid phase extraction based on magnetic graphene oxide nanoparticles and 1-hexadecyl-3-methylimidazolium bromide is used for the removal and determination of chlorophenols in water.

Development and validation of a magnetic solid-phase extraction with high-performance liquid chromatography method for the simultaneous determination of amphetamine and methadone in urine.

The simultaneous determination of amphetamine and methadone was carried out by magnetic graphene oxide nanoparticles, a magnetic solid-phase extraction adsorbent, as a new sample treatment technique. The main factors (the amounts of sample volume, amount of adsorbent, type and amount of extraction organic solvent, time of extraction and desorption, pH, the ionic strength of extraction medium, and agitation rate) influencing the extraction efficiency were investigated and optimized. Under the optimized conditions, good linearity was observed in the range of 100-1500ng/mL for amphetamine and 100-1000ng/mL for methadone. The method was evaluated for determination of AM and methadone in positive urine samples, satisfactory results were obtained, therefore magnetic solid-phase extraction can be applied as a novel method for the determination of drugs of abuse in forensic laboratories.

Mixed hemimicelles solid-phase extraction of cephalosporins in biological samples with ionic liquid-coated magnetic graphene oxide nanoparticles coupled with high-performance liquid chromatographic analysis

A novel mixed hemimicelles solid phase extraction based on magnetic graphene oxide (Fe3O4/GO) and ionic liquid (IL) was developed for the simultaneous extraction and determination of trace cephalosporins in spiked human urine. The high surface area and excellent adsorption capacity of the graphene oxide after modification with1-hexadecyl-3-methylmidazoliumbromide(C16mimBr) were utilized adequately in the solid phase extraction(SPE) process. A comprehensive study of the parameters affecting the extraction recovery, such as the zeta-potential of magnetic graphene oxide, amounts of magnetic graphene oxide and surfactant, pH of solution, ionic strength, extraction time, and desorption condition were optimized. A comparative study on the use of different surfacant-coated Fe3O4/GO NPs as sorbents was presented. Good linearity (R2>0.9987) for all calibration curves was obtained. The LODs were ranged between 0.6 and 1.9ng mL−1 for the cephalosporins and the LOQs were 1.5 to 5.5, respectively. Satisfactory recoveries(84.3% to 101.7%)and low relative standard deviations from 1.7% to 6.3% in biological matrices were achieved. The mixed hemimicelles magnetic SPE (MSPE) method based on ILs and Fe3O4/GO NPs magnetic separation has ever been successfully used for pretreatment of complex biological samples.

A combination of β-cyclodextrin functionalized magnetic graphene oxide nanoparticles with β-cyclodextrin-based sensor for highly sensitive and selective voltammetric determination of tetracycline and doxycycline in milk samples

Highly sensitive and selective determination of tetracycline and doxycycline in milk samples using solid phase extraction followed by differential pulse voltammetric determination on a β-cyclodextrin modified carbon paste sensor.