Saturation Magnetization Value Research Articles

Influence of CoFe2O4 Content on the Multifunctional Properties of BiFeO3-CoFe2O4 Core-Shell Nanocomposites

The utilization of magnetoelectric composites, particularly core-shell configurations, enhances their versatile applications in various sectors such as medicine and data storage. Among these composites, the perovskite-spinel combination is distinguished by its significant potential. A series of (1-x) BiFeO3-(x) CoFe2O4 (where x = 0.0, 0.2, 0.5, and 1.0) nano core-shell structures were synthesized using a sol-gel auto-combustion method to explore their multifunctional capabilities. Structural analyses identified peaks corresponding to both perovskite and spinel phases. Field Emission Scanning Electron Microscopy revealed a reduction in average particle size with an increase in CoFe2O4 content .The particle size in the BFO80-CFO20 sample has been reduced to 34 nm. Additionally, Transmission Electron Microscopy images of the BFO80-CFO20 sample highlighted the evolution of core-shell structures. Our findings indicate that higher CFO concentrations significantly affect the dielectric, ferroelectric, and optical properties. The bandgaps of the nanocomposites BFO80-CFO20 and BFO50-CFO50 were estimated to be 1.43 eV and 1.39 eV, respectively. Magnetic analysis showed increases in both saturation magnetization and remanent magnetization with increased CFO content, while the coercive field followed a different trend. The saturation magnetization values for the samples BFO, BFO80-CFO20, BFO50-CFO50, and CFO were calculated as 0.205, 14.612, 28.374, and 74.105 , respectively. The measured values for the same samples were 0.08, 5.07, 11.34, and 34.01 , respectively. Further, the electrochemical properties were thoroughly investigated using cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy.

Spin dynamics investigation and structural analysis of ambient scalable Sr2+ doped zirconium ferrite nanoparticles synthesized by low temperature auto combustion route

Microwave spin resonance behaviour of Sr2+ doped Zirconium ferrite Zr1-xSrxFe2O4; (0 ≤ x ≥ 0.20) nanoparticles synthesized by auto combustion route has been investigated by electron paramagnetic resonance (EPR) which show a broad ferromagnetic resonance signal with a superimposed hump signal which is attributed to ferrite Fe3+ ions and oxygen vacancies which is in agreement with XRD and XPS. EPR shows low spin concentration and smaller relaxation time for Zr0.80Sr0.20Fe2O4 which can be used for hyperthermia and for use as a MRI contrast agent. EDS and XPS confirms the presence of Zr, Sr, Fe, O, and C and HRTEM images confirm growth along (220) and (311) with an interatomic distance of 0.3327 nm and 0.2622 nm respectively, thus, authenticating the formation of spinel structure in agreement with FTIR studies. The magnetic behaviour (M − H loop) shows high saturation magnetization and higher value of effective magnetocrystalline anisotropy (Keff) for Zr0.80Sr0.20Fe2O4.

Microwave-absorbing behavior of rare-earth-ion-doped copper manganese nanoferrites in X-band frequency

In this study, the technology important Cu0.5Mn0.5Fe2O4 and Cu0.5Mn0.5Fe1.80RE0.2O4 (RE = La, Gd, Nd, and Dy) nanoferrites were synthesized via sonochemical method and characterized to overcome the electromagnetic pollution problems. Crystalline, morphological, electrical, magnetic, and microwave-absorbing parameter were identified by doping of RE (La, Gd, Nd, and Dy) in Cu0.5Mn0.5Fe2O4 nanoferrites. The XRD analysis revealed a cubic spinel structure with a single-phase composition for Cu0.5Mn0.5Fe2O4 nanoferrites whereas Cu0.5Mn0.5Fe1.80RE0.2O4 (RE = La, Gd, Nd, and Dy) nanoferrites had a cubic structure with the presence of a secondary phase. SEM images confirmed the spherical shape of the particle and the grain size within the range of 19.25–28.19 nm, with elemental stoichiometry confirmed by EDS spectra. The dielectric constant and conductivity of Cu0.5Mn0.5Fe1.80RE0.2O4 nanoferrites were low at higher frequencies, which lead good candidates for microwave-absorbing technologies. The substitution of RE decreases saturation magnetization (43.38–23.96 emu/g) and squareness ratio values of prepared nanoferrites were less than 0.5. The SET values of the prepared nanoferrites were in the range of 32.31–41.81 dB. The minimal reflection loss (RL) values of Cu0.5Mn0.5Fe2O4 and Cu0.5Mn0.5Fe1.80RE0.2O4 nanoferrites were less than 10 dB and which indicated that the prepared nanoferrites possessed great potential for applications as microwave-absorbing materials.

SUPERPARAMAGNETIC HYDROPHILIC MOLECULARLY IMPRINTED NANOPARTICLES FOR AN EFFICIENT AND SELECTIVE REMOVAL OF TETRACYCLINE FROM WATER

In this work, a novel superparamagnetic hydrophilic molecularly imprinted nanomaterial for the removal of tetracycline (TC) was synthesized utilizing magnetite (Fe3O4) as the magnetic core, TC as the template molecule, 3-aminopropyltriethoxysilane (APTES) as the functional monomer, and tetraethoxysilane (TEOS) as the cross-linker. Initially, Fe3O4 magnetic nanoparticles (MNP) coated with SiO2 (MNP@SiO2) were synthesized, followed by TC molecular imprinting on the nanoparticles. Initially, Fe3O4 MNP coated with SiO2 (MNP@SiO2) were synthesized, followed by TC molecular imprinting on the nanoparticles. The synthesis method for MNP@SiO2 was optimized, and DLS analysis of 10 replicates showed a nanoparticle size of 70.1 ± 5.8 nm, indicating high method reproducibility. The MNP@SiO2, as well as the imprinted (MNP@SiO2-MIP) and non-imprinted (MNP@SiO2-NIP) nanomaterials, were characterized by FTIR, TEM, VSM, XRD, DLS, Z potential, and BET analysis. The saturation magnetization (Ms) values were 43 emu/g for MNP@SiO2 and 32 emu/g for both MNP@SiO2-MIP and MNP@SiO2-NIP, confirming suitability for magnetic separation using external magnets. Batch binding experiments conducted in water and methanol assessed adsorption isotherms and binding kinetics, with data fitting the Langmuir isotherm model better than the Freundlich model. The developed MIP exhibited significant selectivity against other molecules with similar functional groups and size. In water, the adsorption capacity of the MNP@SiO2-MIP was 23 mg/g, with an imprinting factor of 2.2. Furthermore, the MIP demonstrated good regeneration performance. The material was tested on TC-spiked tap water samples, achieving 80.1% TC removal with high reproducibility (3.2%, n=3). Combining hydrophilic superparamagnetic nanoparticles with molecular imprinting enhances their potential applications in environmental remediation, antibiotic purification, and drug delivery.

Synthesis-Dependent Structural and Magnetic Properties of Monodomain Cobalt Ferrite Nanoparticles

This research examines the structural and magnetic properties of monodomain cobalt ferrite nanoparticles with the formula (Co1−xFex)A[Fe2−xCox]BO4. The particles were synthesized using various methods, including coprecipitation (with and without ultrasonic assistance), coprecipitation followed by mechanochemical treatment, microemulsion, and microwave-assisted hydrothermal techniques. The resulting materials were extensively analyzed using X-ray diffraction (XRD) and magnetic measurements to investigate how different synthesis methods affect the structure and cation distribution in nanoscale CoFe2O4. For particles ranging from 15.8 to 19.0 nm in size, the coercivity showed a near-linear increase from 302 Oe to 1195 Oe as particle size increased. Saturation magnetization values fell between 62.6 emu g−1 and 74.3 emu g−1, primarily influenced by the inversion coefficient x (0.58–0.85). XRD analysis revealed that as the larger Co2+ cations migrate from B- to A-sites (decreasing x), the lattice constants and inter-cation hopping distances increase, while the average strength of super-exchange interactions decreases. This study establishes a connection between the magnetic properties of the synthesized samples and their structural features. Importantly, this research demonstrates that careful selection of the synthesis method can be used to control the magnetic properties of these nanoparticles.

The Impact of Surface Modifier on Magnetic Nanoparticle Properties and Their Application in CD3+T Cell Separation.

Fe3O4 nanoparticles occupy a pivotal position in the realm of nanobiology due to their nontoxic, biocompatible, and superparamagnetic properties. This study examines the influence of surface modifiers on the properties of magnetic nanoparticles. Poly(methacrylic acid) (PMAA), poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSM), trisodium citrate (TSC), carboxymethylcellulose (CMC), and carboxymethylated-dextran 40 (CMD40) were introduced into a one-pot solvothermal method to synthesize magnetic nanoparticles. TEM, the 4-(bromomethyl)-6,7-dimethoxy coumarin (BMMC) absorption assay, and the Bradford method were employed to characterize the diameter, carboxyl content, and protein immobilization ability of the nanoparticles, respectively. The findings revealed that CMD40-modified magnetic nanoparticles (CMD40-MNPs) exhibited the highest carboxyl content and streptavidin (SA) immobilization content, reaching 6.5 × 10-7 mol/mg and 375 μg/mg, respectively. In contrast, CMC-modified magnetic nanoparticles displayed opposite trends. This is primarily attributed to dextran's unique molecular structure, which enhances its water solubility and biocompatibility, thereby facilitating contact with Fe3O4 nanoparticles in aqueous solutions. CMD40-MNPs possess a saturation magnetization value of 60.90 emu/g and can be collected within (60 ± 5) s using a standard magnetic separator. Cytotoxicity assays demonstrated that CMD40-MNPs are nontoxic to cells. A cell sorting strategy utilizing the binding of SA-CMD40-MNPs and biotin antihuman CD3 antibody-modified cell suspensions was employed to isolate CD3+T cells. The results indicate that the purity and efficiency of targeted CD3+T cells are 85.2% and 61.5%, respectively.

Chemical activation and magnetization of carbonaceous materials fabricated from waste plastics and their evaluation for methylene blue adsorption.

In this study, novel adsorbents were synthesized via the activation and magnetization of carbon spheres, graphene, and carbon nanotubes fabricated from plastics to improve their surface area and porosity and facilitate their separation from aqueous solutions. Fourier transform infrared spectroscopy "FTIR", X-ray diffraction "XRD", energy-dispersive X-ray spectroscopy "EDX", transmission electron microscope "TEM", and X-ray photoelectron spectroscopy "XPS" affirmed the successful activation and magnetization of the fabricated materials. Further, surface area analysis showed that the activation and magnetization enhanced the surface area. The weight loss ratio decreased from nearly 60% in the case of activated graphene to around 25% after magnetization, and the same trend was observed in the other materials confirming that magnetization improved the thermal stability of the fabricated materials. The prepared carbonaceous materials showed superparamagnetic properties according to the magnetic saturation values obtained from vibrating sample magnetometry analysis, where the magnetic saturation values were 33.77, 38.75, and 27.18 emu/g in the presence of magnetic activated carbon spheres, graphene, and carbon nanotubes, respectively. The adsorption efficiencies of methylene blue (MB) were 76.9%, 96.3%, and 74.8% in the presence of magnetic activated carbon spheres, graphene, and carbon nanotubes, respectively. This study proposes efficient adsorbents with low cost and high adsorption efficiency that can be applied on an industrial scale to remove emerging pollutants.

Graphene-based Sm-doped Co-ferrite for environmental applications

A graphene-based Sm-doped Co-ferrite CoSmFe-G nanosample was created using the citrate auto-combustion method. It acts as an antibacterial agent and heavy metal remover. The sample’s physical properties were analyzed using various techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (FE-SEM), zeta potential, and vibrating sample magnetometer (VSM) measurements. The XRD results confirmed the presence of a single-phase cubic spinel structure. The experimental results indicated that doping with graphene and samarium significantly altered the magnetic properties of CoSmFe-G nanoparticles, reducing the saturation magnetization (MS) values to 35.759 emu/g. The sample showed antibacterial properties against both gram-positive and gram-negative bacteria, with inhibition zones measuring 12–14.5 mm in diameter. Additionally, the sample exhibited efficient (Pb2+) adsorption, with a maximum removal capacity of 99.8% and a multilayer adsorption mechanism indicated by the pseudo-second-order isotherm and Freundlich model matching. The study explores the binding interactions for lead removal and highlights the potential of using graphene-based Sm-doped Co-ferrite (CoSmFe-G) nano samples as a bio-adsorbent and antibacterial agent. This could lead to practical and efficient solutions for water disinfection.

Investigating the optical and magnetic properties of engineered multifunctional graphene oxide and potential application in medical physics and nonlinear optics‏

Herein, the synthesis of multifunctional engineered GOs with the structure of GO@Fe3O4-ligands-CdTe quantum dots (QDs) by an environment-friendly aqueous method was reported. l-cystein (Cys), 3-trimethoxysilyl-propanethiol (TMSP), and glutathione (GSH) were selected as ligands. The as-prepared GO@Fe3O4-ligands-CdTe QDs hybrid nanostructures were characterized by different methods. The findings indicate that the nanocomposites of GO@Fe3O4–ligands–CdTe QDs demonstrate superparamagnetic properties at room temperature. The saturation magnetization values for GO@Fe3O4, GO@Fe3O4-Cys-CdTe, GO@Fe3O4-GSH-CdTe, and GO@Fe3O4-TMSP-CdTe, are 25, 14, 16, and 2 emu g−1, respectively. These nanocomposites show stable and strong luminescence at 580-600 nm. The magnetic nanostructures also reveal the absorption wavelength at 300-490 nm. Using TMSP ligand as a bridge between QDs and magnetic GOs, the luminescence of the nanostructure has not decreased much compared to CdTe QDs. The use of Cys ligand preserves the saturation magnetism of the nanocomposite more than magnetic GO, and the dispersed nanostructure is stable in water. Furthermore, the transverse and longitudinal optical (TO and LO) phonon modes of prepared GO@Fe3O4–ligands–CdTe QDs were obtained by Kramers-Kronig (KK) relations based on fourier-transform infrared (FTIR) spectroscopy. The Z-scan results show that the type of used ligand has a great effect on the nonlinear optical (NLO) properties of the final product. The largest NLO parameters are related to GO@Fe3O4- TMSP -CdTe QDs, and the values of nonlinear absorption coefficient and nonlinear refractive index were obtained as 2.17×10−3(cm/W) and10.27×10−8(cm2/W), respectively. As a result, GO@Fe3O4–ligands–CdTe QDs nanostructures can be considered as promising multifunctional nanostructures for various biomedical applications and NLO devices.

Zinc/Magnesium Ferrite Nanoparticles Functionalized with Silver for Optimized Photocatalytic Removal of Malachite Green.

Water pollution is a major environmental challenge. Due to the inefficiency of conventional wastewater treatment plants in degrading many organic complex compounds, these recalcitrant pollutants end up in rivers, lakes, oceans and other bodies of water, affecting the environment and human health. Semiconductor photocatalysis is considered an efficient complement to conventional methods, and the use of various nanomaterials for this purpose has been widely explored, with a particular focus on improving their activity under visible light. This work focuses on developing magnetic and photoactive zinc/magnesium mixed ferrites (Zn0.5Mg0.5Fe2O4) by sol-gel and solvothermal synthesis methods, which are two of the most important and efficient methods used for the synthesis of ferrite nanoparticles. The nanoparticles (NPs) synthesized by the sol-gel method exhibited an average size of 14.7 nm, while those synthesized by the solvothermal method had an average size of 17.4 nm. Both types possessed a predominantly cubic structure and demonstrated superparamagnetic behavior, reaching a magnetization saturation value of 60.2 emu g-1. Due to the high recombination rate of electrons/holes, which is an intrinsic feature of ferrites, surface functionalization with silver was carried out to enhance charge separation. The results demonstrated a strong influence of adsorption and of the deposition of silver. Several optimization steps were performed during synthesis, allowing us to create efficient catalysts, as proved by the almost full removal of the dye malachite green attaining 95.0% (at a rate constant of 0.091 min-1) and 87.6% (at a rate constant of 0.017 min-1) using NPs obtained by the sol-gel and solvothermal methods, respectively. Adsorption in the dark accounted for 89.2% of the dye removal for nanoparticles prepared by sol-gel and 82.8% for the ones obtained by the solvothermal method. These results make mixed zinc/magnesium ferrites highly promising for potential industrial application in effluent photoremediation using visible light.

Tuning optical, magnetic, and electrical parameters of CuFe2O4 nanoparticles incorporated with GO and ZnO using a facile synthesis

Nano-ferrites, metal oxides, and carbon-based nanomaterials have been used frequently to enhance optical and magnetic prospects for latent applications. Copper ferrite/Graphene Oxide and Zinc Oxide (CuFe2O4/GO/ZnO) ternary nanocomposite synthesized by hydrothermal route showed dramatically good outcomes as the band gap energy value of synthesized nanocomposite approaches to 2.4 eV. Furthermore, the light absorbance of CuFe2O4 increases by adding ZnO and GO. The experimental data revealed the face-centered cubic structure (FCC) of pure spinal ferrite (CuFe2O4) nanoparticles even after adding ZnO and GO. The 2θ peak observed at 31.70° with (220) hkl planes indicates the successful addition of ZnO nanoparticles in CuFe2O4/GO nanocomposite. XRD graph, the absence of characteristic peaks of GO revealed the intercalation of CuFe2O4 nanoparticles with GO layers. In SEM images, agglomeration among CuFe2O4 nanoparticles is observed due to the magnetic interaction of nano-crystallite with a high surface-to-volume (S/V) ratio. VSM can be used to determine the magnetic properties of as-synthesized samples at moderate temperatures under 0–0.5 and ± 5 tesla. In CuFe2O4/GO/ZnO ternary nanocomposite, the saturation magnetization value reduces from 2.071 to 1.365 emu/g due to the addition of ZnO nanoparticles. The loops were narrowed showing a decrease in the coercive field with the addition of ZnO nanoparticles in CuFe2O4/GO ternary nanocomposite material. Moreover, the study of electrical properties of pure CuFe2O4 and CuFe2O4/GO/ZnO ternary nanocomposite revealed that the values of dielectric constant and tangent loss decrease at high frequencies owing to surface charge polarization and intrinsic dipole interactions. The study of the electrical properties of both pure CuFe2O4 and the CuFe2O4/GO/ZnO ternary nanocomposite reveals that the dielectric constant (ε’) and tangent loss (tanδ) exhibit a decreasing trend as the frequency increases. This behavior is attributed to surface charge polarization and intrinsic dipole interactions. At lower frequencies, both samples display elevated values for these properties, which stabilize as the frequency increases beyond 2 MHz. Notably, high AC conductivity is observed in both samples, attributed to increased capacitance and resistance.

Effects of La-Co Co-Substitution and Magnetic Field Pressing on the Structural and Magnetic Properties of SrM Hexaferrites

We carefully investigated the effects of La-Co co-substitution and magnetic field pressing (MFP) on the structural and magnetic properties of SrM hexaferrites. Samples composed of Sr1−xLaxFe12−xCoxO19 were sintered at 1230 °C for 2 h in air with sintering additives composed of 0.7 wt% CaCO3 and 0.7 wt% SiO2. A single M-type phase was confirmed to exist up to x = 0.3. Rietveld refinement revealed a slight decrease in lattice parameter a and the unit cell volume (Vcell) with an increasing x, while parameter c showed a significant decrease. The saturation magnetization (Ms) values increased from 70.90 to 72.40 emu/g with an increasing x from 0.0 to 0.15 and then decreased to 71.38 emu/g with further increasing of x to 0.3, while the anisotropy field (Ha) increased from 17.7 to 25.9 kOe, leading to a continuous increase in the intrinsic coercivity (Hci), from 3.52 to 5.00 kOe, respectively. Using the MFP process, the c-axis of M-type hexaferrite grains could be effectively aligned to the applied field direction, which significantly affected the microstructures and, thus, magnetic properties of samples. Unlike non-MFP samples, exhibiting a significant increase in the average grain size (davg) but almost unaltered average thickness (tavg) with an increasing x from 0.0 to 0.3, MFP-processed samples exhibited almost unaltered davg values but a continuous decrease in tavg. Consequently, the variation in remanent flux density (Br) versus x followed that of Ms versus x and thus exhibited the highest Br of 4.05 kG for x = 0.15, leading to the highest maximum energy product {(BH)max} of 3.62 MGOe. With an increasing x from 0.0 to 0.3, the Hci values continuously increased from 3.14 to 3.84 kOe mainly due to a continuous increase in Ha, although they were significantly lowered in comparison with those of non-MFP samples because of a large increase in Br for a given composition x. A higher Mr/Ms ratio always resulted in a larger (BH)max in our samples regardless of x. A careful comparison of the microstructures and magnetic properties between MFP and non-MFP samples provided valuable insights into a broad area of permanent magnet optimization.

Effective Co2+ removal from aqueous solution and industrial wastewater using ZIF-7 and MnFe2O4-modified walnut shell biochar composite

In this study, we developed a novel magnetic composite of walnut shell biochar (WSB) and modified it with ZIF-7 for the purpose of removing Co2+ ions. We conducted a comprehensive evaluation of its performance in Co2+ removal, considering various factors such as contact time, temperature, adsorbent dose, pH, and initial Co2+ concentration. Utilizing response surface methodology-central composite design (RSM-CCD), we examined the interactions between these variables. The specific surface area and magnetic saturation value of the WSB/MnFe2O4/ZIF-7 composite were determined as 170.560 m2.g−1 and 23.469 emu.g−1, respectively. ANOVA analysis indicated that our model effectively captures the interactions between variables, with a high R2 value of 0.9982, explaining 99.82 % of the experimental data. Optimal conditions for maximum Co2+ adsorption efficiency (99.05 %) were identified as follows: a contact time of 44.82 min, pH of 6.04, adsorbent dose of 0.947 mg.L-1, temperature of 25.55 °C, and Co2+ concentration of 11.13 mg.g−1. Kinetic studies revealed that the Pseudo 2nd order kinetic model provided the best fit to the experimental data. The negative entropy parameter indicated a decrease in disorderliness during the adsorption process, while the exothermic nature of adsorption was confirmed by enthalpy values of −92.751 and −40.511 kJ.mol−1 for WSB/MnFe2O4/ZIF-7 and WSB, respectively. Furthermore, the Langmuir isotherm model demonstrated excellent fitting to the isotherm results, suggesting the dominance of homogeneous surfaces in adsorption. The maximum adsorption capacities for Co2+ using WSB/MnFe2O4/ZIF-7 and WSB were determined to be 29.26 and 22.39 mg.g−1, respectively. The WSB/MnFe2O4/ZIF-7 magnetic composite demonstrates promising potential for efficiently removing Co2+ from both natural water sources and industrial wastewater, highlighting its versatility and effectiveness in environmental remediation applications.

Efficient adsorptive removal of 2,4-dichlorophenoxyacetic acid (2,4-D) using biomass derived magnetic activated carbon nanocomposite in synthetic and simulated agricultural runoff water

This study focused on evaluating the efficacy of a magnetic activated carbon material (CPAC@Fe3O4) derived from pods of copper pod tree in adsorbing the toxic herbicide, 2,4- (2,4-D) from aqueous solutions. The synthesized CPAC@Fe3O4 adsorbent, underwent various characterization techniques. FESEM images indicated a rough surface, incorporating iron oxide nanoparticles, while EDS analysis confirmed the presence of elements like Fe, O, and C. Notably, the CPAC@Fe3O4 exhibited high surface area (749.10 m2/g) and pore volume (0.5351 cm³/g), confirming its mesoporous nature. XRD investigations identified distinct signals associated with graphitic carbon and magnetite nanoparticles, while VSM analysis verified its magnetic properties with a high magnetic saturation value (2.72 emu/g). The adsorption process was exothermic, with a decrease in adsorption capacity at higher temperatures. Freundlich isotherm provided the best fit for the adsorption, and the pseudo-second-order equation effectively described the kinetics. Remarkably, the maximum adsorption capacity ranged from 246.43 to 261.03 mg/g, surpassing previously reported values. The ΔH° value (−8.67 kJ/mol) suggested a physisorption mechanism, and the negative ΔG° values established the spontaneous nature. Furthermore, the synthesized adsorbent demonstrated exceptional reusability, allowing for up to five cycles of adsorption-desorption operations. When applied to simulated agricultural runoff, CPAC@Fe3O4 showcased a significant adsorption capacity of 160.71 mg/g for 50 mg/L 2,4-D, using a 0.2 g/L dosage at pH 2. This study showcased the transformation of copper pod biomass into a valuable magnetic nanoadsorbent capable of efficiently eliminating the noxious 2,4-D pollutant from aqueous environments.

Synthesis and characterization of magnetic molecularly imprinted polymers for the rapid and selective determination of clofazimine in blood plasma samples

Clofazimine (CLF) is a riminophenazine derivative and a new therapeutic option with high efficacy for patients with rifampicin-resistant tuberculosis (TB). The blood levels of CLF are low and suboptimal, so therapeutic drug monitoring is required. Prior to this study, there were no molecular imprinting–based solid phase extraction (SPE) sorbents that could be used to determine the blood CLF levels. Hence, we prepared a magnetic molecularly imprinted polymer (MMIPs) to capture CLF. We employed computational selection of a functional monomer and crosslinker and confirmed these selections based on the association constant (Ka) and a Job plot. We synthesised MMIPs with two surface modifiers and characterized the polymers. Our computational analysis based on the bond energy revealed that methyl methacrylate (MMA) was the most suitable functional monomer at a CLF-to-MMA molar ratio of 1:4. Based on the bond energy, the most suitable crosslinker was trimethylolpropane trimethacrylate (TRIM) at a CLF-to-TRIM molar ratio of 1:1. We determined the Ka of MMA and TRIM in different solvents. Isopropanol produced the highest Ka. The Job plot showed that a template-to-MMA-to-TRIM molar ratio of 1:4:20 was optimal to synthesize imprinted polymer in isopropanol. We prepared MMIPs using two different modifiers, namely aminopropyltrimethoxysilane (APTES) and oleic acid (OA), using the ratio determined from the Job plot. Physical characteristic tests carried out using FT-IR, SEM-EDS, PSA, BET and VSM, showed that the synthesis was success with a spherical and uniform agglomeration of particles, also a flat surface with many holes with a particle size of MMIP-APTES and MMIP-OA respectively 0.14 μm and 0.28 μm, showed a surface area for MMIP-APTES is 2874.51 m2/g and MMIP-OA 2913.07 m2/g, exhibiting superparamagnetic properties with a saturation magnetization value of MMIP-APTES 21.1 emu/g−1 and MMIP-OA 49.9 emu/g−1. Adsorption capacity result showed that MMIP-OA fits well with the Langmuir model, while MMIP-APTES fits better with the Freundlich. Application of MMIP-SPE (Magnetic Molecular Imprinted Polymer-Solid Phase Extraction) APTES resulted 92.3 ± 6.1 % and MMIP-SPE-OA 51.5 ± 8.1 % for recovering CLF in blood. The result of selectivity test also showed that MMIP-SPE-APTES is better than MMIP-SPE-OA and selectively recover CLF from human blood plasma existed together with other TB-Drugs. The study result shows that MMIPs with APTES modification can be used for CLF determination in human blood plasma.

Development of a magnetite nanocomposite based on expanded graphite/chitosan for efficient removal of brilliant green dye from aqueous solutions

ABSTRACT In this research, to develop an efficient and magnetic graphite-based nanocomposite (Fe3O4/EG-chitosan), the natural flake graphite was first expanded to improve its active surface area. The expanded graphite (EG) was then functionalized and magnetized with chitosan and Fe3O4 nanoparticles to increase its adsorption performance. Structure of EG/chitosan and nanocomposite Fe3O4/EG-chitosan were determined and confirmed by FT-IR, XRD, EDX, FESEM, VSM, zeta potential measurement and BET surface area measurements. The surface area of EG was improved from 10.13 to 83.08 m2/g after the functionalization of it using chitosan. Fe3O4/EG-chitosan exhibited a lower magnetization saturation value (30.9 emu/g) in compared with pure Fe3O4 NPs (60.2 emu/g). The fabricated nanocomposite was then applied to adsorb BG dye from aqueous media. The optimal removal of 98% BG dye was achieved at pH 8.0, adsorbent dosage 0.04 g, initial concentration 50 ppm, and temperature 293 K. The adsorption of BG is described well with the pseudo-second order kinetic model and the Freundlich isotherm model. The results also showed that the maximum adsorption capacity of BG dye was 21.8 mg/g using the Langmuir isotherm model. In addition, after 6 adsorption-desorption cycles, the adsorption capacity of the developed Fe3O4/EXG-chitosan toward BG remains high (90%).

Thermal-responsive β-cyclodextrin-based magnetic hydrogel as a de novo nanomedicine for chemo/hyperthermia treatment of cancerous cells

A novel thermal-responsive β-cyclodextrin-based magnetic hydrogel [β-cyclodextrin-graft-poly(N-isopropylacrylamide)/Fe3O4 (β-CD-g-PNIPAAm/Fe3O4)] was fabricated as a novel nanomedicine for chemo/hyperthermia treatment of cancer cells. Firstly, β-CD was modified by maleic anhydride (MA) followed by copolymerization with NIPAAm monomer and thiol-end capped Fe3O4 nanoparticles (NPs) in the presence of a crosslinker through acrylamide–thiol polymerization system to afford a magnetic hydrogel. The saturation magnetization (δs) value for developed hydrogel was determined to be 8.2 emu g−1. The hydrogel was physically loaded with an anticancer agent, doxorubicin hydrochloride (Dox). The encapsulation efficiency (EE) of drug into the hydrogel was obtained as 73 %. The system represented acceptable thermal-triggered drug release behavior that best fitted with Higuchi model, demonstrating the release of drug is mostly controlled by diffusion mechanism. The anticancer performance of the β-CD-g-PNIPAAm/Fe3O4-Dox was evaluated using MCF7 cells by MTT-assay. In addition, flow cytometry analyses showed considerable cellular uptake of Dox in the cells treated with β-CD-g-PNIPAAm/Fe3O4-Dox (∼70 %) compared to free Dox (∼28 %). As results, in time period of 48 h by combination of chemo- and hyperthermia-therapies, the developed system displayed greater anticancer efficiency than the free Dox.

Antiepileptic drug-loaded and multifunctional iron oxide@silica@gelatin nanoparticles for acid-triggered drug delivery

The current study developed an innovative design for the production of smart multifunctional core-double shell superparamagnetic nanoparticles (NPs) with a focus on the development of a pH-responsive drug delivery system tailored for the controlled release of Phenytoin, accompanied by real-time monitoring capabilities. In this regard, the ultra-small superparamagnetic iron oxide@silica NPs (IO@Si MNPs) were synthesized and then coated with a layer of gelatin containing Phenytoin as an antiepileptic drug. The precise saturation magnetization value for the resultant NPs was established at 26 emu g-1. The polymeric shell showed a pH-sensitive behavior with the capacity to regulate the release of encapsulated drug under neutral pH conditions, simultaneously, releasing more amount of the drug in a simulated tumorous-epileptic acidic condition. The NPs showed an average size of 41.04 nm, which is in the desired size range facilitating entry through the blood–brain barrier. The values of drug loading and encapsulation efficiency were determined to be 2.01 and 10.05%, respectively. Moreover, kinetic studies revealed a Fickian diffusion process of Phenytoin release, and diffusional exponent values based on the Korsmeyer-Peppas equation were achieved at pH 7.4 and pH 6.3. The synthesized NPs did not show any cytotoxicity. Consequently, this new design offers a faster release of PHT at the site of a tumor in response to a change in pH, which is essential to prevent epileptic attacks.

Investigation of Crystallographic, Morphological, Magnetic and Electrochemical Properties of La‐Doped Cu‐CoFe2O4 Spinel Ferrites

AbstractThis research presents the successful synthesis of Cu0.79Co0.21LaxFe2‐xO4 (0.0 ≤ x ≤ 0.8) (spinel ferrite) nanoparticles via the sol‐gel auto combustion technique, with varying La3+ dopant concentrations. In this study, the estimated crystallite size (D) is found to be in the range of (27.92–40.90) nm. The microstructural parameter determination in XRD data is improved using Rietveld refinement. Fourier Transform Infrared Spectroscopy (FTIR) spectra exhibit two distinct metal stretching vibrational bands within (400–600) cm−1 range, a characteristic fingerprint region for all ferrites. Field Emission Scanning Electron Microscopy (FESEM) analysis reveals the agglomeration of particles due to magnetic interactions and non‐uniform distribution of average particle sizes ranging from (1.06–1.87) µm. Energy Dispersive X‐Ray Analysis (EDX) validates the chemical composition's accuracy. Owing to the dilution effect resulting from the introduction of non‐magnetic La3+ ions into the ferrite structure, there is a reduction in the saturation magnetization value, decreasing from 37.28 to 6.24 emu g−1 in the Vibrating Sample Magnetometery (VSM) study. The electrochemical analysis reveals the impressive electrochemical characteristics of the newly developed ferrites, highlighting a remarkable specific capacitance of 270.0 F g−1. This finding positions them as highly promising contenders for a wide range of energy storage supercapacitor applications.

Fabrication and characterization of rubidium ferrites by the solution‐based combustion method using diverse organic fuels

Fabrication and characterization of rubidium ferrites by the solution‐based combustion method using diverse organic fuels