A New Powerful Magnetic Dark Catalyst Based on rGO/Fe3O4/CdSe Nanocomposite for Ultrafast Degradation of Methylene Blue Dye.

In the present study, Rgo/Fe3O4/CdSe as a dark catalyst material was synthesized by a refluxing method. The synthesized magnetic nanocomposites were studied by various analyses such as Fourier transform infrared (FTIR), energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), Raman, Zeta and vibrating sample magnetometer (VSM). Characterization of structural analysis showed that the nanocomposites were successfully synthesized. The absorption spectrum was used to determine the dark catalyst activity of rGO/Fe3O4/CdSe nanocomposite. Analysis of the absorption spectrum showed that the prepared nanocomposites degrade the MB organic dye completely (100%) after 2 min of stirring in the dark, also experimenting with different pH showed that the best performance for the degradation of MB occurs in neutral and alkaline media. The Raman spectrum analysis showed that the Fe3O4/CdSe quantum dots (QDs) were correctly incorporated on the reduced graphene oxide (rGO) nanosheets. Zeta potential analysis showed that rGO/Fe3O4/CdSe has a large amount of negative charge on its surface and the surface charge increased by about 16 mV compared to the Fe3O4/CdSe compound. BET and BJH techniques were used to determine the effective surface area and pore size diameter, BET results to determine the effective surface area showed that by adding graphene to the compound, the specific surface area increased from 42.877 m2g-1 to 54.1896 m2g-1. The radical scavenger experiment showed that electrons play an essential role in the degradation process. VSM analysis showed that the prepared nanocomposites have excellent superparamagnetic behavior, this advantage enables the easy collection of nanocatalysts by magnets from wastewater after dye degradation.

A novel nanocomposite for photocatalytic rhodamine B dye removal from wastewater using visible light.

Providing safe access to water and addressing the impact of waterborne diseases, which claim over two million lives annually, is a major contribution to water purification. The study introduces a novel nanocomposite, Ch/Fe3O4/α-MoO3, which exhibits outstanding photocatalytic efficacy under visible light. An in-depth investigation of the nanocomposite's synthesis, characterization, and photodegradation mechanisms reveals its outstanding capabilities. Photocatalytic activity is influenced by the catalytic dose, pH, dye concentration, and reaction time, according to the study. A response surface method is used to determine the optimal conditions for Rhodamine B degradation, which results in 96.3% removal efficiency at pH 8.5, dye concentration 25 mg/L, nanocomposite dose at 22 mg/L, and reaction time 50 min. As a result of its high surface area, biocompatibility, availability, and magnetization with iron compounds, Chitosan is an excellent substrate for enhancing the photocatalytic properties of MoO3 nanoparticles. A nanocomposite with an energy band of 3.18 eV exhibits improved visible light absorption. This study confirms the nanocomposite's recyclability and stability, affirming its practicality. Besides dye removal, it offers hope for the global quest for clean water sources by addressing a broader range of waterborne contaminants. By combining molybdenum and magnetite, nanocomposite materials facilitate the degradation of pollutant and bacteria, contributing positively to society's quest for clean and safe water. It emphasizes the role nanotechnology plays in preserving human health and well-being in combating waterborne diseases.

Polypyrrole-decorated bentonite magnetic nanocomposite: A green approach for adsorption of anionic methyl orange and cationic crystal violet dyes from contaminated water.

In the presented study, a novel polypyrrole-decorated bentonite magnetic nanocomposite (MBnPPy) was synthesized for efficient removal of both anionic methyl orange (MO) and cationic crystal violet (CV) dyes from contaminated water. The synthesis of this novel adsorbent involved a two-step process: the magnetization of bentonite followed by its modification through in-situ chemical polymerization. The adsorbent was characterized by SEM/EDX, TEM/SAED, BET, TGA/DTA-DTG, FTIR, VSM, and XRD studies. The investigation of the adsorption properties of MBnPPy was focused on optimizing various parameters, such as dye concentration, medium pH, dosage, contact time, and temperature. The optimal conditions were established as follows: dye concentration of Co (CV/MO) at 100 mg/L, MBnPPy dosage at 2.0 g/L, equilibrium time set at 105 min for MO and 120 min for CV, medium pH adjusted to 5.0 for MO dye and 8.0 for CV dye, and a constant temperature of 303.15 K. The different kinetic and isotherm models were applied to fit the experimental results, and it was observed that the Pseudo-2nd-order kinetics and Langmuir adsorption isotherm were the best-fitted models. The maximal monolayer adsorption capacities of the adsorbent were found to be 78.74 mg/g and 98.04 mg/g (at 303.15 K) for CV and MO, respectively. The adsorption process for both dyes was exothermic and spontaneous. Furthermore, a reasonably good regeneration ability of MBnPPy (>83.45%/82.65% for CV/MO) was noted for up to 5 adsorption-desorption cycles with little degradation. The advantages of facile synthesis, cost-effectiveness, non-toxicity, strong adsorption capabilities for both anionic and cationic dyes, and easy separability with an external magnetic field make MBnPPy novel.

Advanced Photodegradation of Azo Dye Methyl Orange Using H2O2-Activated Fe3O4@SiO2@ZnO Composite under UV Treatment.

The Fe3O4@SiO2@ZnO composite was synthesized via the simultaneous deposition of SiO2 and ZnO onto pre-prepared Fe3O4 nanoparticles. Physicochemical methods (TEM, EDXS, XRD, SEM, FTIR, PL, zeta potential measurements, and low-temperature nitrogen adsorption/desorption) revealed that the simultaneous deposition onto magnetite surfaces, up to 18 nm in size, results in the formation of an amorphous shell composed of a mixture of zinc and silicon oxides. This composite underwent modification to form Fe3O4@SiO2@ZnO*, achieved by activation with H2O2. The modified composite retained its structural integrity, but its surface groups underwent significant changes, exhibiting pronounced catalytic activity in the photodegradation of methyl orange under UV irradiation. It was capable of degrading 96% of this azo dye in 240 min, compared to the initial Fe3O4@SiO2@ZnO composite, which could remove only 11% under identical conditions. Fe3O4@SiO2@ZnO* demonstrated robust stability after three cycles of use in dye photodegradation. Furthermore, Fe3O4@SiO2@ZnO* exhibited decreased PL intensity, indicating an enhanced efficiency in electron-hole pair separation and a reduced recombination rate in the modified composite. The activation process diminishes the electron-hole (e-)/(h+) recombination and generates the potent oxidizing species, hydroxyl radicals (OH˙), on the photocatalyst surface, thereby playing a crucial role in the enhanced photodegradation efficiency of methyl orange with Fe3O4@SiO2@ZnO*.

Synergistic Effect Evaluation of Magnetotherapy and a Cationic-Magnetic Nanocomposite Loaded with Doxorubicin for Targeted Drug Delivery to Breast Adenocarcinoma.

This work investigates the synergistic effect of magnetotherapy and a novel cationic-magnetic drug delivery system on inhibiting breast cancer cell growth and other tissues. First, super-paramagnetic magnetite (Fe3O4) nanoparticles were coated with doxorubicin-imprinted poly(methacrylic acid-co-diallyl dimethylammonium chloride) [Fe3O4/poly(MAA-DDA)]. The cationic-magnetic nanocomposite (CMC) was characterized using XRD, FT-IR, VSM, TGA, TEM, FESEM, EDS, DLS, and BET. In vitro analyses, including drug release kinetics, cytotoxicity, and hemolytic assays, confirmed this novel CMC's good drug release profile and biocompatibility. Finally, in vivo experiments on BALB/c mice were designed to evaluate the synergistic effect of magnetotherapy on targeted drug delivery using the CMC. In vivo fluorescence imaging evaluated the drug distribution in different tissues of mice. Tumor volume evaluation demonstrated the efficiency of the CMC and magnetotherapy in preventing tumor growth; the two techniques significantly reduced tumor volume. Histopathological analysis proved that applying magnetotherapy in conjunction with the cationic-magnetic drug delivery system significantly prevented tumor cell proliferation and increased apoptosis with limited impact on other tissues. Also, Dox and Fe concentrations in different tissues confirmed the efficient drug delivery to tumor cells.

Enhanced photocatalytic degradation of crystal violet dye and high-performance electrochemical supercapacitor applications of hydrothermally synthesised magnetic bifunctional nanocomposite (Fe3O4/ZnO).

The present investigation employed a facile hydrothermal approach for the fabrication of Fe3O4/ZnO dual-functional magnetic nanocomposite. Supercapacitor and visible-light-driven photocatalytic applications of the material were explored. X-ray diffraction, Fourier transform infrared spectra, ultraviolet-visible diffuse reflectance spectra (UV-vis/DRS), field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray spectroscopy, and vibrating sample magnetometer were used to analyse the nanocomposite's structural, morphological, optical, and magnetic properties. The FE-SEM analysis demonstrated that the surface morphology of Fe3O4, ZnO, and the Fe3O4/ZnO nanocomposite consisted of nanoparticles, nanoflakes, and nanoparticles adhered to the nanoflakes, respectively. The maximum specific capacitance of the electrode based on the Fe3O4/ZnO nanocomposite was measured to be 736.36 Fg-1at a scan rate of 5 mVs-1. The electrode also demonstrated remarkable cycling stability, retaining 86.5% of its capacitance even after 3000 cycles. The Fe3O4/ZnO nanocomposite was found to have an optical bandgap of 2.7 eV, an average particle size of 22.5 nm, and a saturation magnetization of 68.7 emu g-1. The photocatalysis experiment was conducted using the optimised settings, which included a pH of 7.0, a dye concentration of 30 mg l-1, a catalyst dose of 1 g l-1, and a contact time of 120 min. The Fe3O4/ZnO nanocomposite exhibited a notable degradation efficiency towards crystal violet dye upon exposure to visible light, achieving a degradation efficiency of 96.9%. This performance surpassed that of pure ZnO, which attained a degradation efficiency of 70.2%. The nanocomposite exhibited a rate constant of 2.80 × 10-2min-1, which was found to be notably higher than that of pure ZnO (0.8 × 10-2min-1), as determined through modelling (pseudo-first order linear fit). The radical scavenger experiments indicated that the superoxide radicals and hydroxyl radicals are the primary reactive species. The Fe3O4/ZnO photocatalyst can be effectively isolated using a bar magnet. Remarkably, the photocatalytic efficiency of the material remained almost entirely intact even after undergoing four cycles of recycling. In addition, this research opens up exciting new possibilities for use in fields like energy storage and pollution control.

In situ preparation of MOF-199 into the carrageenan-grafted-polyacrylamide@Fe3O4 matrix for enhanced adsorption of levofloxacin and cefixime antibiotics from water.

In this research study, a novel method, an in-situ growth approach, to incorporate metal-organic framework (MOF) into carrageenan-grafted- polyacrylamide-Fe3O4 substrate was introduced. Carrageenan-grafted-polyacrylamide-Fe3O4/MOF nanocomposite (kC-g-PAAm@Fe3O4-MOF-199) was fabricated utilizing three stages. In this way, the polyacrylamide (PAAm) was grafted onto the carrageenan (kC) backbone via free radical polymerization in the presence of methylene bisacrylamide (MBA) as cross-linker and Fe3O4 magnetic nanoparticles. Next, the kC-g-PAAm@Fe3O4 was modified by MOF-199 via an in-situ solvothermal approach. Several analyses such as Fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-Dispersive X-ray Spectroscopy (EDX), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET) demonstrated the successful synthesis of kC-g-PAAm@Fe3O4-MOF-199 magnetic hydrogel nanocomposite. The XRD pattern of magnetic hydrogel nanocomposite illustrated characteristic peaks of Fe3O4, neat kC, and MOF-199 with enhanced crystallinity in comparison with kC-g-PAAm@Fe3O4. TGA showed it has a char yield of 24 wt% at 800 °C. VSM confirmed its superparamagnetic behavior (with Ms of 8.04 emu g-1), and the BET surface area of kC-g-PAAm@Fe3O4-MOF-199 was measured at 64.864 m2 g-1, which was higher than that of kC-g-PAAm@Fe3O4 due to the highly porous MOF-199 incorporation with a BET surface area of 905.12 m2 g-1). The adsorption effectiveness of kC-g-PAAm@Fe3O4-MOF-199 for eliminating cephalosporin and quinolones antibiotics, i.e., Cefixime (CFX) and Levofloxacin (LEV) from the aquatic area was considered. Several experimental setups were used to evaluate the efficacy of adsorption, such as solution pH, amount of adsorbent, contact duration, and initial concentration. The maximum adsorption capacity (Qmax) of the prepared magnetic hydrogel nanocomposite was found to be 2000 and 1666.667 mg-1 for LEV and CFX using employing 0.0025 g of adsorbent. The Freundlich isotherm model well described the experimental adsorption data with R2CFX = 0.9986, and R2LEV = 0.9939. And the adsorption kinetic data were successfully represented by the pseudo-second-order model with R2LEV = 0.9949 and R2CFX = 0.9906. Hydrogen bonding, π-π interaction, diffusion, and entrapment in the hydrogel network all contributed to the successful adsorption of both antibiotics onto the kC-g-PAAm@Fe3O4-MOF-199 adsorbent. Other notable physicochemical properties include the three-dimensional structure and availability of the reactive adsorption sites. Moreover, the adsorption/desorption efficacy of magnetic hydrogel nanocomposites was not significantly diminished after four cycles of recovery.

Magnetic activated carbon synthesized using rubber fig tree leaves for adsorptive removal of tetracycline from aqueous solutions.

The current study emphasizes the activated carbon fabrication from rubber fig leaves, the establishment of its composite with iron oxide nanoparticles (RFAC@Fe2O3), and its relevance in the adsorptive elimination of tetracycline. The physical and functional properties of RFAC@Fe2O3 nanocomposite were uncovered by multiple approaches. Elemental analysis portrayed the existence of carbon, oxygen, and iron, while FESEM analysis revealed that Fe2O3 nanoparticle agglomerates were entrenched in the activated carbon matrix rendering it a rough abrasive texture. FT-IR analysis reported the presence of functional groups attributing to CC, -OH, crystalline iron oxide, and Fe-O stretching vibrations, and XRD corroborated graphitic crystalline structure, oxygenated functional groups attached to carbon accompanied by crystalline plane corresponding to Fe2O3 nanoparticles. XPS spectra depicted signature peaks for C, O, and Fe, while VSM studies designated its superparamagnetic nature. The high surface area (662.73 m2/g), pore size (3.12 nm), and mesoporous nature of RFAC@Fe2O3 make it apt for the adsorption of pollutants from contaminated samples. The adsorption of tetracycline (50 ppm) by RFAC@Fe2O3 was maximum at pH 4.0. As the nanocomposite dosage and stirring speed increased to 2.0 g/L and 150 rpm, maximum adsorption was observed due to more active binding sites and improved mixing. Freundlich isotherm along with pseudo-second-order model well described adsorption process divulging that tetracycline was adsorbed onto RFAC@Fe2O3 composite in multi-layers by chemisorption. Thermodynamic analysis signified negative values for ΔG°, while positive values for ΔH° and ΔS were obtained, indicating spontaneous feasible endothermic adsorption.

Cerium ions immobilized magnetic graphite nitride decorated with L-Alanyl-L-Glutamine as new chelator for enrichment of phosphopeptides.

Cerium ions immobilized magnetic graphite nitride material have been prepared using L-Alanyl-L-Glutamine as the new chelator. The resulting Fe3O4/g-C3N4-L-Ala-L-Gln-Ce4+, as an immobilized metal ion affinity chromatography (IMAC) sorbent, was reusable. This is due to the strong coordination interaction between L-Alanyl-L-Glutamine and cerium ions. After a series of characterizations, the magnetic nanocomposite showed high surface area, good hydrophilicity, positive electricity, and magnetic response. Fe3O4/g-C3N4-L-Ala-L-Gln-Ce4+ had high sensitivity (0.1 fmol), selectivity (α-/ß-casein/bovine serum albumin, 1:1:5000), and good recyclability (10 cycles). A total of 647 unique phosphopeptides mapped to 491 phosphoproteins were identified from A549 cell lysate by nano LC-MS analysis.

Adsorptive removal of AB113 dye using green synthesized hydroxyapatite/magnetite nanocomposite.

In the present study, magnetite nanoparticles (Fe3O4NPs) synthesized using Thunbergia grandiflora leaf extract as a reducing agent were doped with hydroxyapatite sourced from waste bivalve clamshells to produce hydroxyapatite/magnetite nanocomposite (HA/Fe3O4NPs). The magnetic nanocomposite was examined using several characterization techniques. The results of XRD and FESEM, analysis showed HA/Fe3O4NPs have a crystalline phase and irregular spherical particles respectively. EDAX and FTIR confirmed the presence of specific elements and functional groups of both iron oxide and hydroxyapatite nanoparticles respectively. The surface area and superparamagnetic property of the composite were determined by BET and VSM analysis. Central Composite Design (CCD) was used to optimize the adsorption process to remove of AB113 from aqueous solutions. The optimal adsorption efficiency was found out to be 94.38% at pH 8, AB113 dye concentration 54 ppm, HA/Fe3O4NPs dose 84 mg, and an agitation speed of 174 rpm. The monolayer Langmuir isotherm was the best model with a sorption capacity of 109.98 mg/g which was higher than the reported values. The pseudo-second-order kinetic model displayed a good fit with an R2 = 0.99. Thermodynamic parameters were assessed which confirmed the exothermic adsorption process. Therefore, the synthesized magnetic nanocomposite can be employed as a novel nanoadsorbent for the removal of anionic dyes from waste effluents.

Cadmium ion removal from aqueous media using banana peel biochar/Fe3O4/ZIF-67.

In the present study, banana peel waste was used as a suitable source for biochar production. The banana peel biochar (BPB) was modified using Fe3O4 magnetic and ZIF-67 nanoparticles. The modification of the BPB surface (4.70 m2/g) with Fe3O4 and Fe3O4/ZIF-67 significantly increased the specific surface of the nanocomposites (BPB/Fe3O4: 78.83 m2/g, and BPB/Fe3O4/ZIF-67: 1212.40 m2/g). The effect of pH, temperature, contact time, adsorbent dose, and concentration of Cd2+ on the efficiency of the Cd2+ adsorption was explored. Maximum adsorption efficiencies for BPB (97.76%), BPB/Fe3O4 (97.52%), and BPB/Fe3O4/ZIF-67 (99.14%) were obtained at pH 6, Cd2+ concentration of 10 mg/L, times of 80 min, 50 min, and 40 min, and adsorbent doses of 2 g/L, 1.5 g/L, and 1 g/L, respectively. Thermodynamic measurements indicated that the process is spontaneous and exothermic. The maximum capacity of Cd2+ adsorption using BPB, BPB/Fe3O4, and BPB/Fe3O4/ZIF-67 were obtained 20.63 mg/g, 30.33 mg/g, and 50.78 mg/g, respectively. The Cd2+ adsorption using magnetic nanocomposites followed the pseudo-first-order kinetic model. The results showed that studied adsorbents especially BPB/Fe3O4/ZIF-67 have a good ability to adsorb-desorb Cd2+ and clean an effluent containing pollutants.

Surface magnetization of hydrolyzed Luffa Cylindrica biowaste with cobalt ferrite nanoparticles for facile Ni2+ removal from wastewater.

A novel magnetic adsorbent based on hydrolyzed Luffa Cylindrica (HLC) was synthesized through the chemical co-precipitation technique, and its potential was evaluated in the adsorptive elimination of divalent nickel ions from water medium. Morphological assessment and properties of the adsorbent were performed using FTIR, SEM, EDX, XRD, BET, and TEM techniques. The effect of pH, temperature, time and nickel concentration on the removal efficiency was studied, and pH = 6, room temperature (25 °C), contact time of 60 min, and Ni2+ ion concentration of 10 mg.L-1 were introduced as the optimal values. At optimal conditions, the removal efficiency of Ni2+ ions using HLC and HLC/CoFe2O4 magnetic composite was calculated as 96.38 and 99.13%, respectively. The adsorption process kinetic followed a pseudo-first-order model. Langmuir isotherm was suitable for modelling the experimental data of the Ni2+ adsorption. The maximum elimination capacity of HLC and HLC/CoFe2O4 samples was calculated as 42.75 and 44.42 mg g-1, respectively. Furthermore, thermodynamic investigations proved the spontaneous and exothermic nature of the process. The adsorption efficiency was decreased with increasing the content of Ca2+ and Na + cations in aqueous media. During reusability of the synthesized adsorbents, it was found that after 8 cycles, no significant decrease has occurred in the adsorption efficiency. In addition, real wastewater treatment results proved that HLC/CoFe2O4 magnetic composite has an excellent performance in removal of heavy metals pollutant from shipbuilding effluent.

Magnetic Fe/Fe3C@C Nanoadsorbents for Efficient Cr (VI) Removal.

Magnetic carbon nanocomposites (α-Fe/Fe3C@C) synthesized employing fructose and Fe3O4 magnetite nanoparticles as the carbon and iron precursors, respectively, are analyzed and applied for the removal of Cr (VI). Initial citric acid-coated magnetite nanoparticles, obtained through the co-precipitation method, were mixed with fructose (weight ratio 1:2) and thermally treated at different annealing temperatures (Tann = 400, 600, 800, and 1000 °C). The thermal decomposition of the carbon matrix and the Fe3O4 reduction was followed by thermogravimetry (TGA) and Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, Raman spectroscopy, SQUID magnetometry, and N2 adsorption-desorption isotherms. A high annealing temperature (Tann = 800 °C) leads to optimum magnetic adsorbents (high magnetization enabling the magnetic separation of the adsorbent from the aqueous media and large specific surface area to enhance the pollutant adsorption process). Cr (VI) adsorption tests, performed under weak acid environments (pH = 6) and low pollutant concentrations (1 mg/L), confirm the Cr removal ability and reusability after consecutive adsorption cycles. Physical adsorption (pseudo-first-order kinetics model) and multilayer adsorption (Freundlich isotherm model) characterize the Cr (VI) absorption phenomena and support the enhanced adsorption capability of the synthesized nanostructures.

Glutathione-stabilized Fe3 O4 nanoparticles as the sorbent for magnetic solid-phase extraction of diazepam and sertraline from urine samples through quantitation via high-performance liquid chromatography.

The synthesis and application of glutathione-coated magnetic nanocomposite were introduced with the purpose of developing a stable, cheap, operationally convenient, simple, fast, sensitive, and selective device for the microextraction of diazepam and sertraline for the first time. The prepared glutathione@Fe3 O4 nanocomposite was used as the sorbent in the form of magnetic solid-phase extraction. Afterward, the extracted analytes were desorbed by organic solvent and analyzed by high-performance liquid chromatography-ultraviolet detection. Several influential variables such as desorption time, desorption volume, sample pH, extraction time, and sorbent amount were screened through Plackett-Burman design and then optimized via Box-Behnken design. The obtained results showed that the above-mentioned method enjoys a good linear range (0.2-500 µg/L) with the coefficient of determination higher than 0.9927, low limits of determination (0.07-0.24 µg/L), acceptable limits of quantification (0.22-0.93 µg/L), good enrichment factors (128 and 153), and good spiking recoveries (95-105%) for diazepam and sertraline under the obtained optimized condition. Analyzing the real samples results in the confirmation of the presented method and it can be applied for the analysis of various organic compounds in biological samples.

Non-enzymatic monitoring of hydrogen peroxide using novel nanosensor based on CoFe2O4@CdSeQD magnetic nanocomposite and rifampicin mediator.

In this work, a novel strategy was introduced to develop a non-enzymatic hydrogen peroxide (H2O2) sensor based on rifampicin (RIF) electrodeposited on a polyvinylpyrrolidone (PVP)-capped CdSe quantum dot (CdSeQD), CoFe2O4 magnetic nanoparticle-modified glassy carbon electrode (CoFe2O4@CdSeQDs/RIF/GCE). CoFe2O4@CdSeQD magnetic nanocomposite (CoFe2O4@CdSeQD MNCs) was synthesized by a chemical co-precipitation method and characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). To prepare the non-enzymatic H2O2 sensor, firstly, the glassy carbon electrode surface was modified by dropping 10 µL of 5 mg mL-1 CoFe2O4@CdSeQD MNCs. Then, rifampicin was electrodeposited on the activated CoFe2O4@CdSeQDs/GCE by applying a potential of - 0.7 V for 400 s in pH 2.0 phosphate buffer containing 190 µM of rifampicin. Cyclic voltammetry and electrochemical impedance spectroscopy was used to investigate the electrochemical behavior of this sensor and was used for the reduction of H2O2. Construction of the calibration plot for H2O2 was performed using an amperometric method (- 0.2 V vs. Ag/AgCl) at the modified electrode. Two linearity ranges were obtained from 7 to 145 µM and 145 µM to 1.43 mM with sensitivities of 143.01 µA mM-1 and 28.67 µA mM-1 for the first and second linearity ranges, respectively. The detection limit was obtained as 0.38 µM (S/N = 3). Finally, the reliability of the nanosensor was confirmed with real sample analysis in different beverages such as juice and milk with satisfactory recovery results.

Quantitative Drug Release Monitoring in Tumors of Living Subjects by Magnetic Particle Imaging Nanocomposite.

In vivo drug release monitoring provides accurate and reliable information to guide drug dosing. Image-based strategies for in vivo monitoring are advantageous because they are non-invasive and provide visualization of the spatial distribution of drug, but those imaging modalities in use (e.g., fluorescence imaging (FI) and magnetic resonance imaging (MRI)) remain inadequate because of the low tissue penetration depth (for FI) or difficulty with quantification of release rate and signal convolution with noise sources (for MRI). Magnetic particle imaging (MPI), employing superparamagnetic nanoparticles as the contrast agent and sole signal source, enables large tissue penetration and quantifiable signal intensity. These properties make it ideal for application to in vivo drug release monitoring. In this work, we design a superparamagnetic Fe3O4 nanocluster@poly(lactide-co-glycolide acid) core-shell nanocomposite loaded with a chemotherapy drug (doxorubicin) which serves as a dual drug delivery system and MPI quantification tracer. The as-prepared nanocomposite can degrade under a mild acidic microenvironment (pH = 6.5), which induces a sustained release of doxorubicin and gradual decomposition of the Fe3O4 nanocluster, causing the MPI signal changes. We showed that nanocomposite-induced MPI signal changes display a linear correlation with the release rate of doxorubicin over time (R2 = 0.99). Utilizing this phenomenon, we successfully established quantitative monitoring of the release process in cell culture. We then performed in vivo drug release monitoring in a cancer therapy setting using a murine breast cancer model by injecting the nanocomposite, monitoring the drug release, and assessing the induced tumor cell kill. This study provides an improved solution for in vivo drug release monitoring compared to other available monitoring strategies. This translational strategy using a biocompatible polymer-coated iron oxide nanocomposite will be promising in future clinical use.

Concentrative isolation of uranium traces in aqueous solutions via resurfaced-magnetic carbon nanotube suspension.

The concentrative isolation of metal traces from aqueous solutions is of vital importance for environmental and industrial processes. Developing reliable systems of nanoscale that can be fine-tuned to effectively isolate these metals remains an intriguing aim which can potentially beget economic benefits and mitigate major environmental concerns. Here we demonstrate a conceptual metal extraction system where magnetic multi-wall carbon nanotubes (M-MWCNTs) are surface-equipped with a molecular network of polyethylenimine (PEI) to serve as a reusable nano-ionic exchanger, referred to as "M-MWCNTs-PEI". The designed nano-ionic exchanger forms readily stable suspensions with the metal-bearing aqueous solutions eliminating the need for vigorous agitation. Besides, it can be magnetically manipulated and separated in/from the solution. To exemplify its potential for the isolation of metal traces, the M-MWCNTs-PEI was tested with the uranium trace ions in aqueous media. The M-MWCNTs-PEI featured distinct sorption capacity of ~488 mg/g at pH 6, with moderate, but stable, binding affinity toward uranium ions. As such, excellent isolation performance is demonstrated while bound uranium ions are effectively concentrated and recovered from the interfacial PEI molecular network. This was efficiently achieved by exposing the loaded M-MWCNTs-PEI to solutions of small volumes and specific chemistry. Such combined qualities of large capacity and reusability have not been observed with the previously reported ion exchange systems. Altogether, our observations here demonstrate how functional systems of nanoscale can be adapted for industrial applications while this concept can be extended to address other important resources such as rare-earth and lanthanide elements.

Synthesis of Fe2SiO4-Fe7Co3 Nanocomposite Dispersed in the Mesoporous SBA-15: Application as Magnetically Separable Adsorbent.

The mixture containing alloy and oxide with iron-based phases has shown interesting properties compared to the isolated species and the synergy between the phases has shown positive effect on dye adsorption. This paper describes the synthesis of Fe2SiO4-Fe7Co3-based nanocomposite dispersed in Santa Barbara Amorphous (SBA)-15 and its application in dye adsorption followed by magnetic separation. Thus, it was studied the variation of reduction temperature and amount of hydrogen used in synthesis and the effect of these parameters on the physicochemical properties of the iron and cobalt based oxide/alloy mixture, as well as the methylene blue adsorption capacity. The XRD and Mössbauer results, along with the temperature-programmed reduction (TPR) profiles, confirmed the formation of Fe2SiO4-Fe7Co3-based nanocomposites. Low-angle XRD, N2 isotherms, and TEM images show the formation of the SBA-15 based mesoporous support with a high surface area (640 m2/g). Adsorption tests confirmed that the material reduced at 700 °C using 2% of H2 presented the highest adsorption capacity (49 mg/g). The nanocomposites can be easily separated from the dispersion by applying an external magnetic field. The interaction between the dye and the nanocomposite occurs mainly by π-π interactions and the mixture of the Fe2SiO4 and Fe7Co3 leads to a synergistic effect, which favor the adsorption.

Optimization, equilibrium, adsorption behavior and role of surface functional groups on graphene oxide-based nanocomposite towards diclofenac drug.

Aquatic contamination of diclofenac (DCF), an emergent non-steroidal anti-inflammatory drug (NSAIDs), can result in adverse effects to many ecosystems through biomagnification. Hence, introducing effective remediation techniques to sequester the pharmaceutical wastes is highly fundamental to prevent their accumulation in the environment. Generally, adsorption has been presented as a green and efficient approach. Herein, we report the characterization and application of the novel magnetic nanocomposite (GO@CoFe2O4) derived from cobalt-based ferrite (CoFe2O4) and graphene oxide (GO) for DCF adsorption. For the optimization procedure, the response surface methodology (RSM) was adopted to investigate the impacts of DCF concentration (1.6-18.4 mg/L), DCF dosage (0.08-0.92 g/L), and solution pH (2.6-9.4) to find the optimum conditions for DCF removal, at 10.5 mg/L, 0.74 g/L, and pH 4, respectively. For the adsorption experiments, the kinetic, isotherm, thermodynamic, and intraparticle diffusion models were systematically studied. Moreover, we have elucidated the role of functional groups on the surface of GO@CoFe2O4 in enhancing the adsorption of DCF drug. With good removal efficiency (up to 86.1%), high maximum adsorption capacity (32.4 mg/g), GO@CoFe2O4 can be a potential candidate to eliminate DCF drug from water.

Extraction of plasmid DNA by use of a magnetic maghemite-polyaniline nanocomposite.

We describe the use of a hybrid magnetic nanocomposite (HMNC) for the extraction and purification of plasmid DNA (pDNA) from Escherichia coli aqueous solutions. The HMNC, which was synthesized via emulsion polymerization, was characterized by transmission electron microscopy, scanning electron microscopy, UV-Vis spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering and magnetic measurements. The results confirmed the incorporation of polyaniline (Pani) in its conducting form onto a core formed by the magnetic iron oxide, with the hybrid particles presenting an average size of (95 ±â€¯30) nm and a saturation magnetization of 30 emu/g. The yield, purity and quality of the pDNA purified by using the Pani HMNC were evaluated by UV-Vis spectroscopy, agarose gel electrophoresis, and Polymerase Chain Reaction (PCR), respectively. An average yield of ~6.9 µg was obtained in the DNA extraction process, with the collected material presenting a good purity (a ₳260/280 ratio in the 1.68-1.82 range) and an excellent quality, as confirmed by subsequent PCR assays. Hence, this HMNC appears as a promising material for use in pDNA purification protocols, and we suggest that this novel HMNC-based methodology can be of general interest and find widespread application in different biomedical procedures.