Magnetic Graphene Oxide Nanocomposite Research Articles

Cost-effective synthesis of magnetic graphene oxide nanocomposite from waste battery for the removal of arsenic from aqueous solutions: Adsorption mechanism with DFT calculation

In this study, magnetic graphene oxide (MGO-Fe3O4) nanocomposite was prepared by co-precipitating of FeCl3.6H2O and FeCl2.4H2O on waste battery-derived graphene oxide and used as an adsorbent for the efficient removal of As(III) from aqueous solutions. The prepared nanocomposite was characterized by Fourier transformed infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, zeta potential, and a vibrating sample magnetometer. These characterizations revealed that spare like Fe3O4 nanoparticles (10.5 nm) were decorated on graphene oxide nanosheets and showed excellent saturation magnetization (89.73 emu/g). The adsorption of As(III) by MGO-Fe3O4 was optimized by analyzing various parameters. Experiments showed that 98 % of As(III) was removed at neutral pH in a just 20 min, even though the adsorbent dose was only 0.14 g/L. The adsorption kinetic and isotherm were best fitted with the pseudo-second order kinetic and Frendlich isotherm model. The maximum adsorption capacity (qmax) was found to be 50.2 mg/g at room temperature. Thermodynamic studies showed that the As(III) adsorption process was spontaneous and exothermic in nature. The enhanced adsorption capacity and magnetic properties of MGO-Fe3O4 are crucial in the drinking water treatment process due to the easy magnetic separation of MGO-Fe3O4 from aqueous solution after the adsorption process. Density Functional Theory (DFT) was also used to investigate the interaction between MGO-Fe3O4 and As(III), which further suggested that MGO-Fe3O4 and As(III) mostly interact with each other through surface complexation and hydrogen bonding.

Magnetic Graphene Oxide Nanocomposites Boosts Craniomaxillofacial Bone Regeneration by Modulating circAars/miR-128-3p/SMAD5 Signaling Axis.

The ability of nanomaterials to induce osteogenic differentiation is limited, which seriously imped the repair of craniomaxillofacial bone defect. Magnetic graphene oxide (MGO) nanocomposites with the excellent physicochemical properties have great potential in bone tissue engineering. In this study, we aim to explore the craniomaxillofacial bone defect repairment effect of MGO nanocomposites and its underlying mechanism. The biocompatibility of MGO nanocomposites was verified by CCK8, live/dead staining and cytoskeleton staining. The function of MGO nanocomposites induced osteogenic differentiation of BMSCs was investigated by ALP activity detection, mineralized nodules staining, detection of osteogenic genes and proteins, and immune-histochemical staining. BMSCs with or without MGO osteogenic differentiation induction were collected and subjected to high-throughput circular ribonucleic acids (circRNAs) sequencing, and then crucial circRNA circAars was screened and identified. Bioinformatics analysis, Dual-luciferase reporter assay, RNA binding protein immunoprecipitation (RIP), fluorescence in situ hybridization (FISH) and osteogenic-related examinations were used to further explore the ability of circAars to participate in MGO nanocomposites regulation of osteogenic differentiation of BMSCs and its potential mechanism. Furthermore, critical-sized calvarial defects were constructed and were performed to verify the osteogenic differentiation induction effects and its potential mechanism induced by MGO nanocomposites. We verify the good biocompatibility and osteogenic differentiation improvement effects of BMSCs mediated by MGO nanocomposites. Furthermore, a new circRNA-circAars, we find and identify, is obviously upregulated in BMSCs mediated by MGO nanocomposites. Silencing circAars could significantly decrease the osteogenic ability of MGO nanocomposites. The underlying mechanism involved circAars sponging miR-128-3p to regulate the expression of SMAD5, which played an important role in the repair craniomaxillofacial bone defects mediated by MGO nanocomposites. We found that MGO nanocomposites regulated osteogenic differentiation of BMSCs via the circAars/miR-128-3p/SMAD5 pathway, which provided a feasible and effective strategy for the treatment of craniomaxillofacial bone defects.

Adsorption Behaviors and Mechanism of Phenol and Catechol in Wastewater by Magnetic Graphene Oxides: A Comprehensive Study Based on Adsorption Experiments, Mathematical Models, and Molecular Simulations.

This study provides a comprehensive analysis of the adsorption behaviors and mechanisms of phenol and catechol on magnetic graphene oxide (MGO) nanocomposites based on adsorption experiments, mathematical models, and molecular simulations. Through systematic experiments, the influence of various parameters, including contact time, pH conditions, and ionic strength, on the adsorption efficacy was comprehensively evaluated. The optimal contact time for adsorption was identified as 60 min, with the observation that an increase in inorganic salt concentration adversely affected the MGOs' adsorption capacity for both phenol and catechol. Specifically, MGOs exhibited a superior adsorption performance under mildly acidic conditions. The adsorption isotherm was well represented by the Langmuir model, suggesting monolayer coverage and finite adsorption sites for both pollutants. In terms of adsorption kinetics, a pseudo-first-order kinetic model was the most suitable for describing phenol adsorption, while catechol adsorption conformed more closely to a pseudo-second-order model, indicating distinct adsorption processes for these two similar compounds. Furthermore, this research utilized quantum chemical calculations to decipher the interaction mechanisms at the molecular level. Such calculations provided both a visual representation and a quantitative analysis of the interactions, elucidating the underlying physical and chemical forces governing the adsorption phenomena. The findings could not only offer crucial insights for the treatment of coal industrial wastewater containing phenolic compounds with bridging macroscopic observations with microscopic theoretical explanations but also advance the understanding of material-pollutant interactions in aqueous environments.

GELLAN GUM- AND PECTIN-MAGNETIC GRAPHENE OXIDE NANOCARRIERS LOADED WITH CINNAMALDEHYDE FOR MOSQUITO LARVAE CONTROL

Magnetic nanoparticles have evolved over the last few decades as nanocarriers in drug delivery systems for hydrophobic drugs. Here, novel gellan gum magnetic graphene oxide (GG-GO-Fe3O4) and pectin magnetic graphene oxide (PEC-GO-Fe3O4) nanocomposites were prepared to carry cinnamaldehyde to control Aedes aegypti larvae. Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM) and scanning transmission electron microscopy (STEM) were employed to investigate the physicochemical characteristics of the nanocomposites. Entrapment efficiencies and loading capacities of nanocomposites on cinnamaldehyde were examined using ultraviolet-visible analysis. The successful cinnamaldehyde loading was confirmed by C-C and C-O stretches in the FTIR spectra. Results of in vitro release study showed the capabilities of GG-GO-Fe3O4 as a drug carrier system, extending the cinnamaldehyde release period for 36 h, and the release profiles for both nanocomposites fit the Korsmeyer-Peppas kinetic model with correlation coefficient (R2) values of over 0.9809. The cinnamaldehyde-loaded GG-GO-Fe3O4 nanocomposites induced 68% mortality after 72 h of exposure, with LC50 values ranging from 2.0488 and 15.9121 mg/L. The conjugation of GO-Fe3O4 with biopolymers improved the water solubility of cinnamaldehyde by 36.41 to 62.83 times vs. free cinnamaldehyde in water (1.42 mg/mL). Overall, these results are beneficial for researchers dealing with mosquito control and prevention.

Magnetic Graphene Oxide Nanocomposites for Selective miRNA Separation and Recovery.

In this study, we developed magnetic graphene oxide composites by chemically attaching Fe3O4 nanoparticles to graphene oxide nanosheets. Characterization techniques, including Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and transmission electron microscopy (TEM), confirmed the successful synthesis of Fe3O4@GO composites with desirable properties. The resulting composites exhibited superparamagnetic behavior, solubility, and compatibility for efficient miRNA separation. Using miR-29a as a model, we demonstrated the effective binding of miR-29a to the magnetic graphene oxide (GO) composites at an optimal concentration of 1.5 mg/mL, followed by a simple separation using magnetic forces. Additionally, the addition of 5.0 M urea enhanced the miRNA recovery. These findings highlight the potential use of our magnetic graphene oxide composites for the efficient separation and recovery of miR-29a, suggesting their broad applicability in various miRNA-based studies. Further exploration can focus on investigating endogenous miRNAs with aberrant expression patterns, contributing to the advancements in precision medicine.

Magnetic graphene oxide nanocomposites induce cytotoxicity in ADSCs via GPX4 regulating ferroptosis

Magnetic graphene oxide nanocomposites (MGO NPs) have been widely studied in biomedical applications. However, their cytotoxicity and underlying mechanisms remain unclear. In this study, the biosafety of MGO NPs was investigated, and the mechanism involved in ferroptosis was further explored. MGO can produce cytotoxicity in ADSCs, which is dependent on their concentration. Ferroptosis was involved in MGO NP-induced ADSC survival inhibition by increasing total ROS and lipid ROS accumulation as well as regulating the expression levels of ferroptosis-related genes and proteins. GPX4 played a critical role in the MGO NP-induced ADSC ferroptosis process, and overexpressing GPX4 suppressed ferroptosis to increase cell survival. This study provides a theoretical basis for the biosafety management of MGO NPs used in the field of biomedical treatment.

Efficient removal of amoxycillin antibiotics onto magnetic graphene oxide: adsorption performance, mechanism, and regeneration exploration

ABSTRACT The present study was done to synthesise an adsorbent, i.e. magnetic graphene oxide (MGO) nanocomposite, which was performed based on a facile precipitation method and was utilised in experiments for removing amoxycillin (AMX). The characteristics of the prepared adsorbent were defined based on commonly utilised analyses (SEM, XRD, BET, TEM, FTIR, VSM, and pHpzc). According to kinetic studies, the PSO model was found as an applicable model for describing data. Moreover, the two-step diffusion process, i.e. diffusion in the boundary layer and the porous structures, was perceived for the evaluated process based on the IPD model. The isotherm models, including Langmuir, Freundlich, Temkin, and D–R, were employed for fitting data and calculating AMX adsorption capacity, among which Langmuir was the best one; using this model, the maximum adsorption capacities for MGO were 91.4, 103.9, 112.3, and 122.5 mg/g, which were achieved at 20, 30, 40, and 50°C. In addition, a feasible, spontaneous, and endothermic process was found for the adsorption of AMX ions, according to thermodynamic studies. The highest percentage of removal (100%) was obtained for the initial concentration of 25 mg/L at 50°C using the adsorbent dose of 1.5 g/L at a pH of 5 and a contact time of 90 min. The values of 74.4 m2/g and 27.74 emu/g were detected for the specific surface area and saturation magnetisation values of the MGO, respectively. The overall results were representative of the suitability of the MGO as an adsorbent for removing AMX from aqueous media.

Removal of ciprofloxacin and cephalexin antibiotics in water environment by magnetic graphene oxide nanocomposites; optimization using response surface methodology

This study investigates the efficient removal of ciprofloxacin (Cip) and cephalexin (Cep) using magnetic graphene oxide (Fe3O4/GO) as an adsorbent. To this end, the magnetic nanocomposite was synthesized via a co-precipitation method. The surface and properties of the adsorbent were characterized using pHpzc, XRD, FE-SEM, FT-IR, VSM, and TEM techniques. The XRD and FT-IR results were consistent with those of previous results. The FE-SEM and TEM results of the synthesized nanoparticles were less than 30 nm in size and showed a spherical shape. The maximum saturation magnetization of the Fe3O4/GO nanocomposite was 45.97 emu g−1. Also, the pHpzc of the nanocomposite was 6.2. The optimal conditions for independent variables were found to be an antibiotic concentration of 15 mg L−1, pH of 7, a contact time of 33 min, and a nanocomposite amount of 0.55 g. Furthermore, under these optimal conditions, Fe3O4/GO magnetic nanocomposite removed 96.39 % of Cip and 97.69 % of Cep from the water samples. Among different eluents (i.e., acetonitrile, chloroform, methanol, and ammonia), significant desorption of Cip and Cep antibiotics was achieved using methanol. Furthermore, applying the Fe3O4/GO magnetic nanocomposite on real water samples revealed that nanocomposite could remove Cip and Cep antibiotics in the range of 89.96–95.83 %. Considering the high potential of Fe3O4/GO magnetic nanocomposite in removing Cip and Cep antibiotics, it can be considered a suitable candidate for removing antibiotics from contaminated water sources.

Adsorptive removal of tetracycline antibiotic onto magnetic graphene oxide nanocomposite modified with polyvinylpyrroilidone

Disposal of pharmaceutical compounds in wastewaters poses potential environmental risk, especially to aquatic life. Herein, magnetic CuFe2O4-graphene oxide (GO) modified with polyvinylpyrrolidone (PVP) ternary nanocomposite (PMGO) was prepared, by a simple ultrasonic method, and successfully applied to the removal of tetracycline (TC) as a model pharmaceutical species. The defect sites of graphene oxide layers served as nucleation centers that allowed the anchoring of both PVP and CuFe2O4 nanoparticles, resulting in reduced agglomeration chances of GO sheets and thus enhanced its TC removal efficiency. Furthermore, the synthesized PMGO was characterized using SEM-EDS, HRTEM, XRD, XPS, FTIR, BET, and VSM. The removal including was optimized by examining the effects of operating parameters, including, initial TC concentration, solution pH, contact time, and PMGO mass. Adsorption isotherms were examined using three-parameters (Hills and Sips) and two-parameters (Langmuir, Freundlich and Tekman) models. PMGO exhibited a maximum adsorption capacity of 193.8 mg/g according to Sips model that exhibited the best fit to experimental data. Moreover, TC removal fitted the PSO kinetics. The removal mechanism was inferred based on adsorption isotherms and kinetic investigations, as well as changes of medium pH and spectral analysis of PMGO composite after adsorption and revealed that electrostatic attraction, π-π interaction, and H-bonding were essential contributing forces, where a TC monolayer was adsorbed onto the PMGO surface and OH− and H+ exerted competitive effects. Importantly, the synthesized nanocomposite exhibited outstanding performance even in the presence of coexisting species (NaCl and SDS surfactant), as well as excellent reusability for practical applications.

Adsorptive removal of ciprofloxacin from aqueous medium by magnetic guar gum grafted graphene oxide nano composite

In view of the huge quantum of harmful pharmaceuticals being released into the water stream from various sources, eradication or reduction of these harmful chemicals to a minimum permissible limit is of primary importance. The current work reports a two-step fabrication of magnetic guar gum graphene oxide nanocomposite, mGG/GO NC, a bio nanocomposite based on guar gum polymer blended with Graphene oxide decorated with magnetic nanoparticles. It was subsequently examined for its adsorption ability for the sequestration of ciprofloxacin form wastewater. Various techniques including XRD, Raman and FTIR spectroscopy, HRTEM, EDX, FESEM, VSM, pHZPC, and TGA have been employed for the characterization of guar gum as well the nanocomposite. Experimental kinetic and isotherm data obtained from batch adsorption studies when fitted into known models reveals that pseudo second order model and Langmuir isotherm model can best illustrate the behavior of the adsorption process. Thermodynamic studies carried out at varying temperatures confirm the spontaneity and exothermic nature of the adsorption phenomenon. Moreover, a significant extent of recyclability of the nanocomposite is predicted with a retention of adsorption efficiency up to several cycles of adsorption-desorption studies. The novel natural polysaccharide-based nanocomposite can prove to be an excellent adsorbent as evident from a considerably high maximum adsorption capacity value of 555.56 mg g−1. Numerous interactions such as hydrogen bonding, electrostatic, electron-donor acceptor (EDA) or π − π interactions, and hydrophobic interactions act as driving forces in the adsorption mechanism; a synergistic effect of all these interactions may have plausibly resulted in such an excellent adsorption capacity exhibited by mGG/GO NC.

Magnetic functionalized graphene oxide combined with ultra-high performance liquid chromatography for trace detection of succinate dehydrogenase inhibitor fungicides in food.

In this study, an efficient, sensitive, and convenient magnetic solid-phase extraction method combined with ultra-high performance liquid chromatography-tandem mass spectrometry (MSPE-UHPLC-MS/MS) was developed for the simultaneous determination of 19 succinate dehydrogenase inhibitor fungicide residues in six different food matrices The synthesized tetraethylenepentamine magnetic graphene oxide nanocomposite showed the advantages of good dispersibility, large specific surface area (113.93 m2 /g) and large pore volume (0.25 cm3 /g), making it an ideal succinate dehydrogenase inhibitor pretreatment adsorbent. The MSPE-UHPLC-MS/MS method showed linearity in the range of 5.0-800.0μg/kg, with a correlation coefficient (R2 )>0.99, and a limit of quantification of 5μg/kg. The recovery of succinate dehydrogenase inhibitor fungicides was in the range of 71.2%-119.4%. The MSPE method is simple, rapid, and efficient, making it an ideal alternative to sample pretreatment in the determination of trace succinate dehydrogenase inhibitor fungicides in complex matrices.

Visible light assisted photocatalytic degradation of methylene blue using iodine doped Fe3O4-GO composite

Environmental contamination and wastewater discharge from industrial activities are global issues that must be addressed immediately. The uncontrolled discharge of dangerous organic compounds constitutes a significant environmental risk. To solve this issue, heterogeneous photocatalysis with semiconductor metal oxides has appeared as an environmentally benign method for wastewater treatment. Our research aims to create a new iodine-doped magnetic graphene oxide nanocomposite and test its ability to break down the refractory methylene blue dye by photocatalytic techniques using sunlight. The I-Fe3O4-GO composite was synthesized using a facile ultrasonication-assisted co-precipitation method. Several physiochemical techniques were employed for detailed characterization, including SEM-EDX, XRD, FTIR, UV-Vis DRS, and Raman spectroscopy. The band gap value of 2.6 eV was measured using a tauc plot. The I-Fe3O4-GO nanocomposite showed 95% methylene blue degradation under sunlight in about an hour. The improved catalytic efficiency of the synthesized photocatalyst was attained at pH 8, with an I-FeGO dose of 50 mg/100 mL and an oxidant dose of 14 mM. The photocatalyst displayed exceptional photostability after five consecutive reusability cycles. Response surface methodology was the statistical tool for evaluating several interacting parameters for optimizing dye degradation.

Adsorption of chloroquine, propranolol, and metformin in aqueous solutions using magnetic graphene oxide nanocomposite.

The work proposes the application of a nanocomposite formed by graphene oxide and magnetite to remove chloroquine, propranolol, and metformin from water. Tests related to adsorption kinetics, equilibrium isotherms and adsorbent reuse were studied, and optimization parameters related to the initial pH of the solution and the adsorbent dosage were defined. For all pharmaceuticals, adsorption tests indicated that removal efficiency was independent of initial pH at adsorbent dosages of 0.4 g L-1 for chloroquine, 1.2 g L-1 for propranolol, and 1.6 g L-1 for metformin. Adsorption equilibrium was reached within the first few minutes, and the pseudo-second-order model represented the experimental data well. While the equilibrium data fit the Sips isotherm model at 298 K, the predicted maximum adsorption capacities for chloroquine, propranolol, and metformin were 44.01, 16.82, and 12.23 mg g-1, respectively. The magnetic nanocomposite can be reused for three consecutive cycles of adsorption-desorption for all pharmaceuticals, being a promising alternative for the removal of different classes of pharmaceuticals in water.

Novel chitosan/GO@Fe3O4 porous microspheres with magnetic separation function for the removal of Congo red from aqueous solutions

BackgroundDeveloping a novel chitosan porous microsphere with outstanding adsorption performance and magnetic separation function is significant for recycling and purification in wastewater treatment applications. MethodsGO@Fe3O4 (magnetic graphene oxide nanocomposite, MGN) was synthesized by a hydrothermal method, and magnetic chitosan/GO@Fe3O4 porous microspheres (MCMS) were fabricated via inverse emulsion method combined with simple microfluidic technique. The influence of MGN on the microstructures, magnetic separation performance and thermal stability of MCMS was characterized and the efficiency in removing Congo red (CR) from aqueous solutions was evaluated. Significant FindingsThe incorporation of MGN can significantly improve the adsorption performance of MCMS microspheres. The maximum adsorption amount of MCMS for CR achieved was around 395.8 mg g-1 at 308 K. MCMS also exhibited excellent magnetic separation performance and remarkably enhanced thermal stability. Besides, the pseudo-second-order kinetic model can describe the adsorption process for CR well, and the adsorption isotherms closely obeyed the Langmuir isotherm model.

Removal of lead (II) from aqueous solutions using β-cyclodextrin functionalized magnetic graphene oxide nanocomposite, performance, and optimization with response surface methodology

Removal of lead (II) from aqueous solutions using β-cyclodextrin functionalized magnetic graphene oxide nanocomposite, performance, and optimization with response surface methodology

Magnetic graphene oxide nanocomposite as dual-mode genosensor for ultrasensitive detection of oncogenic microRNA

MicroRNA (miRNA) is a noncoding RNA that controls cellular functions and gene expression. Several oncogenic miRNAs that aberrantly expressed in prostate cancer have the potential to be used as biomarkers. We designed multifunctional nanosheets that can capture, detect, and quantify miRNA 183-5p from prostate cancer cells with the aid of a disposable printed electrode and a portable potentiostat. Magnetic reduced graphene oxide (MrGO) has been used as the starting nanocomposite to analyze miRNA. Three cationic dyes—toluidine blue (TBO), thionine, and neutral red—were used to modify MrGO and evaluate its impact on the electron transfer rate. MrGO modified with TBO had the fastest conductivity and a large electrochemically active surface area. Two strategies were used to detect miRNA. One used peroxidase-labeled amplification and the other used TBO as the redox probe intercalating in the miRNA-capture probe duplex. The intercalator method reduced the complications of using peroxidase-labeled probes and exhibited superior performance. The limits of miRNA detection in human serum and urine were 3.73 and 0.86 aM, respectively, with a linear range from 0.1 nM to over 1 aM. The assay time of the intercalator method, including wash, was less than 16 min, and only one sample droplet (5 μL) was needed for analysis. We provided dual-mode genosensors for miRNA detection, which might be used for point-of-care testing. The incorporation of MrGO, screen-printed carbon electrodes, and portable potentiostat can accelerate biomarker detection, simplify analysis, and reduce the time and cost of analysis.

One pot chemical co-precipitation preparation of magnetic graphene oxide-deltamethrin nanoformulations for management of Aedes aegypti

Aedes-borne diseases are of worldwide concern due to the lack of effective medicine and vaccination. Frequent use of chemical intervention has developed insecticide resistance in mosquitoes and posed health risks to humans and the environment, necessitating an effective and safer intervention. Graphene Oxide (GO) is an efficient material that can absorb pesticide particles and release pesticide macromolecules in a controlled manner. With the proposition that magnetic graphene oxide (MGO)-based nanoformulations can be an eco-safe and effective material for pesticide conjugation, the present study synthesized these nanoformulations conjugated with a pyrethroid, deltamethrin (DL) through chemical co-precipitation method. The formulations were validated using biophysical techniques and investigated for their efficacy against Aedes aegypti. The X-ray diffraction (XRD) pattern of nanocomposites showed six intense diffraction peaks of Fe3O4 particles, X-ray photoelectron spectroscopy (XPS) displayed the C1s, O1s, and Fe2p photoelectron lines in the MGO nanocomposite's spectra, while Field Emission Scanning Electron Microscopy (FESEM) revealed the small size and uniformity of Fe3O4 nanoparticles on the GO surface. The individual MGO and DL, as well as MGO-DL binary combinations (1:1, 1:2, and 1:3) imparted significant larval toxicity, demonstrating 30%, 50%, and 85% CTC (Co-toxicity coefficient), respectively. High corresponding Synergistic factor (SF) values indicated significant synergism increasing with the rise in deltamethrin proportion. The MGO-DL combinations also increased irritancy and flight response in adults, the notable synergistic effects imparted by the 1:3 combination. The effective actions of MGO-DL nanoformulations against mosquitoes suggest their possible use for mosquito management as a safer and more operative intervention.

Magnetically purification/immobilization of poly histidine-tagged proteins by PEGylated magnetic graphene oxide nanocomposites

Carbon-based nanomaterials have many applications in biomedicine due to their unique mechanical, chemical, and biological properties. Among them, graphene has received special attention due to its very high specific surface area, high flexibility, and chemical stability. In this study, graphene oxide was first functionalized with amine groups (GO-NH2) and then Fe3O4 nanoparticles were deposited on it using the hydrothermal method. In addition, polyethylene glycol (PEG) was attached to the magnetic graphene nanoparticles to increase their stability and solubility. Finally, PEGylated magnetic graphene nanocomposites were functionalized with nickel-nitrilotriacetic acid (NTA-Ni+2) to bind to the poly-histidine tag in recombinant proteins. The resulting nanocomposites (MG-PEG-NTA-Ni+2) were then used for magnetic immobilization and purification of recombinant β-NGF as a protein with his-tag sequence. Binding and purification were confirmed by FTIR and SDS-PAGE techniques, respectively. Importantly, differentiation of the PC12 cell line into neurons demonstrated that the purified β-NGF was fully functional. Our results suggest that MG-PEG-NTA-Ni+2 nanocomposites may be a suitable alternative to commercial resins for rapid and specific protein immobilization and purification.

Tailoring carboxylatopillar[5]arene-modified magnetic graphene oxide nanocomposites for the efficient removal of cationic dyes.

A carboxylatopillar[5]arene-embellished (CP5) magnetic graphene oxide nanocomposite (MGO@CP5) was smoothly constructed via a mild layer-by-layer method. The morphology, structure, and surface characteristics of this nanocomposite was investigated by field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, zeta potential, and other techniques. Benefiting from a high capture ability for small molecules of CP5 as a supramolecular host molecule, along with a negative surface charge and large surface area of MGO@CP5, this nanocomposite exhibits an ultrafast, efficient adsorption property for representative cationic dyes: methylene blue (MB) and basic fuchsin (BF). The removal efficiency of MB and BF can reach nearly 99% within 3 min, while the maximum adsorption capacity of the two dyes reaches 240 mg g-1 for MB and 132 mg g-1 for BF. Furthermore, owing to excellent magnetic responsiveness from the tight loading of Fe3O4 nanoparticles on graphene oxide, MGO@CP5 could be easily and magnetically separated, regenerated, and reused four times without an evident reduction in the removal efficiency (>95%). Impressively, the adsorption property of MGO@CP5 reveals a strong tolerance to pH changes and ionic strength interference, which renders it a promising adsorbent in the field of water treatment.

Magnetic particle-filled polyaniline-doped graphene oxide nanocomposite-based electrode in application of supercapacitor

In this study, the electrochemical characteristics of magnetic particle-filled conductive polyaniline-doped graphene oxide nanocomposites (MDiPG) were investigated. The graphene oxide was chemically exfoliated from natural graphite flakes by the modified Hummer's method. The nanocomposite was characterised through thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Its electrochemical characteristics were evaluated by cyclic voltammetry and galvanostatic charge/discharge tests. The nanocomposite electrode material was obtained through in situ polymerisation of polyaniline-doped graphene oxide combined with the mixing of a magnetic substance. The supercapacitor cell was composed of symmetric magnetic-derived electrodes, polypropylene separator, and 6M KOH as an electrolyte. The cyclic voltammetry curve study showed a good relation of both materials, where a high specific gravimetric capacitance was achieved at 303 F/g.