Magnetic Oxide Nanoparticles Research Articles

Synthesis of magnetic nanoparticles to detect Sudan dye adulteration in chilli powders

Magnetic nanoparticles were synthesised to extract Sudan dyes from chilli powders. The adsorbents used were magnetic ferroferric oxide nanoparticles coated with polystyrene. The extraction procedures for Sudan dyes comprised liquid-solid extraction and magnetic solid phase extraction. The conditions were optimised to achieve efficient magnetic solid phase extraction, including extraction and desorption time, type and volume of the desorption solvent, and the mass of the adsorbents. Repeatability tests showed satisfactory recovery rates of 80.2–115.8%, with a relative standard deviation <3.8%. The results suggested that the proposed extraction method was effective and efficient to extract Sudan dyes from chilli powders. The extraction process was simpler compared with traditional approaches because the adsorbents can be rapidly removed from the sample matrix using a permanent magnet. The use of recyclable adsorbents decreased the cost greatly. Chilli powder samples collected from local markets in Singapore were tested using the proposed method under optimum conditions.

Bottom-up design of hydrogels through click-chemistry modification of magnetic nanoparticles

The paper describes a modular approach based on click chemistry for the surface modification of magnetic oxide nanoparticles and their covalent inclusion within chemical hydrogels. As a proof of concept, we prepared cobalt ferrite nanoparticles and we modified their surfaces through the reaction with molecules bearing a carboxylic function and, alternatively, either an azide or an alkyne moiety. In the second step, the modified nanoparticles were reacted through a Huisgen 1,3-dipolar cycloaddition with a molecule bearing an unsaturated function and either an alkyne or an azide moiety, respectively. Finally, the particles were successfully copolymerized with acrylamide and N,N&#39;-methylenebisacrylamide to obtain a magnetically responsive hydrogel. This approach could be easily extended towards any type of inorganic oxide nanoparticles and their inclusion within any radically co-polymerized hydrogel.

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.

Magnetic nanoferromanganese oxides modified biochar derived from pine sawdust for adsorption of tetracycline hydrochloride.

In this study, a new type of composite material, namely modified biochar (MBC), was synthesized by loading the magnetic ferromanganese oxide nanoparticles on pine biochar. BET, SEM, and FTIR were employed to analyze the surface properties and pore structures of MBC. In addition, XRD was adopted to examine the crystal structure of MBC. Characterization results showed that the surface area and porosity of MBC have been greatly improved, and the functional groups have been introduced by ferromanganese oxides. Adsorption experiments of tetracycline hydrochloride (TC) including kinetics, isotherms, thermodynamics as well as the influence of pH, salt ion strength, and the environmental risk of MBC, were evaluated. The results revealed that the experimental data conformed to the pseudo-second-order kinetic model and the Freundlich isotherm model. In the adsorption process, MBC showed excellent adsorption ability (maximum capacity for TC 100.74mgg-1) to BC (33.76mgg-1). In isotherm experiments, the maximum adsorption capacity of TC by MBC reached 177.71mgg-1. Toxicity studies showed that the MBC had no harm to the environment. To conclude, MBC has great potential for applications in removing TC from water.

Synthesis, characterization and evaluation of Co3O4 nanoparticles toxicological effect; synthesized by cochineal dye via environment friendly approach

Magnetic oxide nanoparticles (MNPs) have been extensively utilized in a wide range of biomedical applications, in order to improve the efficiency of the MNPs in therapeutic applications, there for in the present work high quality cobalt oxide magnetic nanoparticles were synthesized with a green solid state approach using cochineal powder (a natural and environmentally friendly source) as a biosynthetic precursor. This method is novel, green, simple, one step, surfactant free, solvent free, low temperature and fast. A natural complex of Co(NO3)2 - cochineal prepared and thermally decomposed in 400, 500 and 600 °C. The synthesized-nanoparticles were characterized by; scanning electron microscope (SEM), X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS) and vibrating sample magnetometer (VSM). MTT assay performed to determine the cytotoxicity and anti-cancer effect of the Co3O4 nanoparticles against 4T1 cell lines. Acridine orange/ethidium bromide staining methods, DAPI staining was applied in order to investigate the mechanism of cell death. The effect of the Co3O4 nanoparticles on oxidative stress studied as well using the H2DCF-DA assay used for the reactive oxygen species (ROS) generation study. The results demonstrate that the Co3O4 nanoparticles significantly reduced the survival percentage of 4T1 cells of breast cancer with that IC50 of 2 mg/ml. The dominant mechanism of cell death was apoptosis, along with an increase in cellular oxidative stress. Therefore, the Co3O4 nanoparticles prepared here can be used as a chemotherapeutic agent against invasive breast cancer cells. However, further in vivo study is required to confirm it's effect.

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.

Synthesis and sustainable assessment of thiol-functionalization of magnetic graphene oxide and superparamagnetic Fe3O4@SiO2 for Hg(II) removal from aqueous solution and petrochemical wastewater

Abstract Adsorbents used in adsorption processes play an important role in wastewater treatment technologies. It is therefore of interest how manufactured adsorbents can perform better or be more efficient. Is the adsorption capacity a sufficient indicator to select a good adsorbent? In this study, two nanoadsorbents of Hg(II) were successfully synthesized. They are magnetic graphene oxide (MGO NH-SH) and magnetic nanoparticle (Fe3O4@SiO NH-SH), both functionalized with a thiol group, acetylcysteine. The nanoadsorbents, in addition to their adsorption capacity, were investigated from the viewpoints of reuse and regeneration, economic costs, and environmental impact (carbon footprint). The prepared nanoadsorbents were characterized by FTIR, XRD, TGA, FE-SEM, VSM, AFM, Raman, and elemental analysis. Their adsorption of Hg(II) fits well with the Langmuir isotherm model and follows the pseudo-second-order kinetics. Under optimal conditions, the results of Hg(II) removal from real wastewater and polluted water by MGO NH-SH exhibited a higher adsorption capacity, reuse, and regeneration, and as well lower cost and greenhouse gas emissions compared to Fe3O4@SiO NH-SH. The findings of the present study highlight that MGO NH-SH as a promising adsorbent is more economically and environmentally friendly than Fe3O4@SiO NH-SH in the efficient removal of Hg(II) from real wastewater and polluted water.

Assembly of Magnetic Nano-Fe3O4@GSH-Au NCs Core–Shell Microspheres for the Visualization of Latent Fingerprints

Glutathione (GSH), the protective agent and reducing agent, has been widely used to prepare gold nanoclusters (GSH-Au NCs) with stable fluorescence properties and negative charge of the surface. Meanwhile, polyethyleneimine (PEI) was used as the modification agent to synthesize magnetic ferroferric oxide nanoparticles (Fe3O4) with fantastic dispersibility and positive charge of the surface. Based on the electrostatic adsorption force, magnetic nano-Fe3O4@GSH-Au NCs core–shell microspheres composed of magnetic Fe3O4 nanoparticles modified by PEI as the core and GSH-Au NCs as the shell were assembled. The prepared Fe3O4@GSH-Au NCs microspheres harbored a uniform size (88.6[Formula: see text]nm), high magnetization (29.2[Formula: see text]emu/g) and excellent fluorescence. Due to the coordination bond action between Au atom and sulfhydryl (–SH), amino (–NH2), carboxyl (–COOH) in sweat, Fe3O4@GSH-Au NCs could combine with latent fingerprints. In addition, Fe3O4@GSH-Au NCs with good fluorescence and magnetism could detect fingerprints on various objects. Significantly, the powders were not easy to suspend in the air, which avoided the damage to the health of forensic experts and the fingerprints by only powder contacting. Above all, Fe3O4@GSH-Au NCs was successfully applied to the latent fingerprint visualization, which has great potential in forensic science.

Growth inhibition of mice mammary carcinoma cell line with green synthesized Magnetic Iron Oxide Nanoparticles

Mammary adenocarcinoma represents one of the most cancers that effect woman in Iraq and worldwide. Finding a definitecure for this type of cancer is a target of considerable research in many laboratories over the globe. In this study, a greensynthesized magnetic iron oxide nanoparticles (MNP) was used to specify their ability to inhibit the growth of mice mammarycarcinoma cell line (AMN3), it comes as a preliminary study of wider ongoing research. After successfully synthesizing magneticiron nanoparticles, it employed in different concentrations to expose AMN3 cells for 24 and 48 hours. The viability of theexposed cells was determined using standard MTT assay. The inhibition concentration 50 was determined afterward and usedto test the possibility of inducing apoptosis in the carcinoma cells using a mixture of fluorescent stains acridine orange andpropidium iodide. Results indicated that green synthesized MNP can inhibit the growth of mammary adenocarcinoma cell lineup to 79% and 89% after 24 and 48 hr of incubation with 1000μg/ml. The IC50 of MNP was capable of inducing apoptosis inthis cell line as shown by fluorescence microscope. The standard hemolysis assay used to test the reaction between the greensynthesized magnetic oxide nanoparticles and normal cells. The IC50 of AMN3 cells growth inhibition only induce 14% ofRBC hemolysis, while the percentage induced by negative control was 10%. In conclusion, green MNP have an effect uponcancer cells greater than normal cells. This material must tested against other types of cancer and normal cells to verify itsaction and study mechanisms of apoptosis induction in detail.Key words: Magnetic iron oxide nanoparticles, AMN3, green synthesis, nanotherapy.

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.

Citric acid coated CoFe2O4 nanoparticles transformed through rapid mechanochemical ligand exchange for efficient magnetic hyperthermia applications

Abstract We report the hydrothermal synthesis of uniform size (∼6 nm) oleic acid capped CoFe 2 O 4 (OA-CoFe 2 O 4 ) nanoparticles. These OA-CoFe 2 O 4 nanoparticles were initially hydrophobic and not dispersible in water which were transformed into hydrophilic nanoparticles by modifying their surface with citric acid using a rapid mechanochemical ligand exchange process, which makes CoFe 2 O 4 nanoparticles stable colloidal solution in water. The synthesized citric acid coated CoFe 2 O 4 (CA-CoFe 2 O 4 ) nanoparticles show a high enough and stable zeta potential over 120 days. CA-CoFe 2 O 4 nanoparticles exhibited high biocompatibility under in vitro cell studies. The specific absorption rate (SAR) of the CA-CoFe 2 O 4 nanoparticles was measured by induction heating studies. Upon the exposure of AC external magnetic field, the viability of cancer cells was reduced considerably, suggesting efficient potentiality of these CA-CoFe 2 O 4 nanoparticles for Magnetic Hyperthermia Applications. Present mechanochemical ligand exchange method is proposed as an efficient method for large scale production of biocompatible and water dispersible magnetic oxide nanoparticles for Magnetic Hyperthermia Applications.

Controlled surface/interface structure and spin enabled superior properties and biocompatibility of cobalt ferrite nanoparticles

High quality, crystalline, well-dispersed, and stable magnetic oxide nanoparticles (NPs) of inverse spinel cobalt ferrite (CoFe2O4; CFO) were prepared by a facile, reproducible, and simple hydrothermal route. The transmission electron microscopy, small-angle scattering and X-ray diffraction analyses demonstrate the structural quality of CFO NPs with a controlled size of ∼12 nm. Small-angle scattering experiments demonstrate that the pristine CFO NPs have the individual size ∼8.5 nm and spherical shape. The Raman and infrared spectroscopic measurements further confirm their high chemical quality and cubic symmetry. CFO NPs exhibit a remarkable, maximum coercivity (HC) value of 18.92 kOe, which is the highest value achieved to date. Surface spins and spins canting along with a weak dipolar interaction accounts for the giant HC and large effective anisotropy (11.45 × 106 erg/cm3) of these CFO NPs. The magnetic grain size of NPs reveals that the canted surface spins exist around the magnetic particles. Reorientation of surface spins and interparticle interaction causes the jumping behaviour in M-H hysteresis loops at H = 0. The cell viability of CFO NPs against the cancer (cisplatin resistant ovarian cancer – A2780/CP70) was evaluated to determine their potential application in biomedicine and health science. The mild response of CFO NPs in terms of their anti-proliferative nature against cancer cells and negligible cytotoxicity suggests their human-safe-and-friendly nature which makes them suitable for biomedical/health-related applications. Assessment of toxicity toward human red blood cells (RBC) revealed that hemolysis is less than 5% compared to the positive control confirming the potential applications of CFO NPs targeting human cells and making relevant for adopting them in biomedicine.

Magnetic oxide nanoparticles (Fe3O4) impregnated bentonite clay as a potential adsorbent for Cr(III) adsorption

This paper presents the adsorption of Cr(III)from aqueous solutions using the magnetic oxide impregnated bentonite clay. Results of the study suggested that Fe3O4-Bentonite have excellent sorption potential in removing Cr(III) by conventional adsorption mechanisms. The characterization of impregnated sorbent was made by SEM, XRD, UV–vis and FTIR spectroscopy and salt addition methods. The effect of contact time, pH, metal concentration and dosage amount on the adsorption efficiency were investigated. The results showed that the adsorption capability for the Cr(III) increased by increasing the contact time and initial pH of the solution. The equilibrium data was evaluated by Langmuir, Freundlich and Dubinin-Radushkevich models to determine the nature of adsorption. Maximum capacity for Cr(III) was found 1.27 mmol g−1 at temperature of 283 K. Three kinetic models, Film, Particle, Intra-particle diffusion models and pseudo first order were applied to kinetic data to observe the reaction mechanism. The lower activation energy (less than 42 kJ mol−1) proved the diffusional and physical nature of metal sorption on magnetic sorbent. Thermodynamics parameters indicated the endothermic and spontaneous nature of the sorption process with entropical changes at solid-liquid interface. Moreover, Fe3O4-Bentonite adsorbent was also regenerated and reused for successful recovery.

Magnetically Recoverable Catalysts: Beyond Magnetic Separation.

Here, we discuss several important aspects of magnetically recoverable catalysts which can be realized when magnetic oxide nanoparticles are exposed to catalytic species and catalytic reaction media. In such conditions magnetic oxides can enhance performance of catalytic nanoparticles due to (i) electronic effects, (ii) catalyzing reactions which are beneficial for the final reaction outcome, or (iii) providing a capacity to dilute catalytic metal oxide species, leading to an increase of oxygen vacancies. However, this approach should be used when the magnetic oxides are stable in reaction conditions and do not promote side reactions. Incorporation of another active component, i.e., a graphene derivative, in the magnetically recoverable catalyst constitutes a smart design of a catalytic system due to synergy of its components, further enhancing catalytic properties.

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.

Cholesterol-oxidase-magnetic nanobioconjugates for the production of 4-cholesten-3-one and 4-cholesten-3, 7-dione

Cholesterol oxidase(ChOx) enzyme isolated from Pseudomonas aeruginosa PseA(ChOxP) and Rhodococcus erythropolis MTCC 3951(ChOxR) strains as well as a commercial variant produced by Streptomyces sp.(ChOxS) were immobilized on silane modified iron(II, III)oxide magnetic nanoparticles(MNP) by covalent coupling methods. The nanobiocatalysts in case of ChOxP, ChOxR and ChOxS, retained 71, 91 and 86% of cholesterol oxidase activity respectively, as compared to their soluble counterparts. The catalytic efficiency of the immobilized enzymes on nanoparticles was more than 2.0 times higher than the free enzyme. They also showed enhanced pH and thermal stability. After 10 cycles of operation, the MNP-bioconjugates retained 50, 52 and 51% of residual activity in case of ChOxP, ChOxR and ChOxS respectively. The presence of enzyme on nanoparticles was confirmed by FTIR, SEM and TEM. The nanobiocatalysts were used for the biotransformation of cholesterol and 7-ketocholesterol to 4-cholesten-3-one and 4-cholesten-3, 7-dione respectively, which are industrially and medically important steroid precursors.

UV-Vis-Induced Degradation of Phenol over Magnetic Photocatalysts Modified with Pt, Pd, Cu and Au Nanoparticles.

The combination of TiO2 photocatalyst and magnetic oxide nanoparticles enhances the separation and recoverable properties of nanosized TiO2 photocatalyst. Metal-modified (Me = Pd, Au, Pt, Cu) TiO2/SiO2@Fe3O4 nanocomposites were prepared by an ultrasonic-assisted sol-gel method. All prepared samples were characterized by X-ray powder diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), Mott-Schottky analysis and photoluminescence spectroscopy (PL). Phenol oxidation pathways of magnetic photocatalysts modified with Pt, Pd, Cu and Au nanoparticles proceeded by generation of reactive oxygen species, which oxidized phenol to benzoquinone, hydroquinone and catechol. Benzoquinone and maleic acid were products, which were determined in the hydroquinone oxidation pathway. The highest mineralization rate was observed for Pd-TiO2/SiO2@Fe3O4 and Cu-TiO2/SiO2@Fe3O4 photocatalysts, which produced the highest concentration of catechol during photocatalytic reaction. For Pt-TiO2/SiO2@Fe3O4 nanocomposite, a lack of catechol after 60 min of irradiation resulted in low mineralization rate (CO2 formation). It is proposed that the enhanced photocatalytic activity of palladium and copper-modified photocatalysts is related to an increase in the amount of adsorption sites and efficient charge carrier separation, whereas the keto-enol tautomeric equilibrium retards the rate of phenol photomineralization on Au-TiO2/SiO2@Fe3O4. The magnetization hysteresis loop indicated that the obtained hybrid photocatalyst showed magnetic properties and therefore could be easily separated after treatment process.

Synthesis and catalytic evaluation of Fe3O4/MWCNTs nanozyme as recyclable peroxidase mimetics: Biochemical and physicochemical characterization

AbstractIn this research, the nanocomposite of multiwalled carbon nanotubes and magnetic metal oxide nanoparticles (Fe3O4/MWCNTs), as enzyme mimetic, was synthesized using an in situ chemical reduction method. The structure, composition and morphology of the prepared Fe3O4/MWCNT nanocomposite materials were characterized using X‐ray diffraction, FT‐IR and scanning electron microscopy with energy dispersive X‐ray spectroscopy, respectively. The magnetic properties of the nanocomposite were investigated by the vibrating sample magnetometer. A colorimetric system involving nanozyme, phenol/4‐aminoantipyrine and H2O2 was utilized for the determination of peroxidase mimetic catalytic assay. The obtained results confirmed that the synthesis of Fe3O4/MWCNTs nanostructures was successful. It was found that Fe3O4/MWCNTs nanohybrid exhibited peroxidase‐like activity without any pH limitation. Colorimetric data demonstrated that the prepared nanocatalyst had higher catalytic activity toward H2O2 than MWCNTs. The kinetic parameters of the nanozyme, Km and Vmax, were estimated to be 8.3 mm and 1.4 mm min−1, respectively. The Fe3O4/MWCNTs nanostructures were also successfully applied for glucose detection. In addition, peroxidase‐like activity of the nanozyme increased in the presence of butyl‐imidazolium bromide ionic liquid. These biomimetic catalysts have some advantages, such as simplicity, stability, reusability and cost effectiveness, which makes them great candidates to be used in various fields of biotechnology applications.

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.

Cr–Containing Magnetic Oxides in a Methanol Synthesis: Does Cr Ion Distribution Matter?

AbstractHere, we report on the development of novel Cr‐containing magnetic oxide nanoparticles (NPs) as catalysts for a syngas‐to‐methanol reaction which constitutes a sustainable route to obtain value‐added chemicals. These NPs have been synthesized in a one‐pot reaction by thermal decomposition of Cr acetylacetonate and doping metal acetylacetonates (if used) in the reaction solution of preformed magnetite NPs stabilized by polyphenylquinoxaline. For all the samples, the NP surface is enriched with Cr. At the same time, the Cr species are finely dispersed in the magnetite phase. This exposes Cr catalytic species to reacting molecules and creates an intimate contact between Cr3+ and Fe3O4. As a result, the methanol productivity rate for the Cr‐containing magnetic oxide prepared with 0.5 mmol of the Cr precursor is approximately three orders of magnitude higher than that for the conventional Cu/ZnO/Al2O3 catalyst. Additional doping of this Cr‐containing magnetic oxide with small amounts of Ni or La leads to even higher catalytic activity (by 40–49%).