Magnetic Nano Research Articles

2D-3D magnetic NiFe layered double hydroxide decorated diatomite as multi-function material for anionic, cationic dyes, arsenate, and arsenite adsorption

Three-dimensional diatomite was decorated with a novel magnetic two-dimensional layered double hydroxides nanosheet (DE@NiFe LDH) by the hydrothermal synthesis method. The adsorption of anionic, cationic dyes, As(V), and As(III) was achieved by the synergistic effect of diatomite and NiFe LDH. The newly synthesized materials were characterized by different methods: XRD; FT-IR; zeta potential measurements; N2 adsorption to determine surface area and pore structure; SEM and XPS. The effects of pH, concentrations, contact time and temperature on the adsorption properties were also studied to clarify the mechanism. At adsorption equilibrium (1 h), the adsorption of methyl orange, and methylene blue reached 96.8% and 84.4%, respectively. Maximum sorption of MO, MB, As(III), and As(V) was 134.32, 76.79, 335.69, and 80.58 mg g−1 respectively, exhibiting superior adsorption performance. The thermodynamic parameters of the adsorption process were calculated and indicated that the adsorption process is exothermic. This work provides an idea for the synthesis of low-cost, ideal, and magnetic multifunctional nano adsorbent for anionic, cationic dyes, As(V), and As(III), offering potential applications for practical wastewater purification.

Comparative Evaluation of Different Surface Coatings of Fe3O4-Based Magnetic Nano Sorbent for Applications in the Nucleic Acids Extraction.

Nucleic acid extraction and purification are crucial steps in sample preparation for multiple diagnostic procedures. Routine methodologies of DNA isolation require benchtop equipment (e.g., centrifuges) and labor-intensive steps. Magnetic nanoparticles (MNPs) as solid-phase sorbents could simplify this procedure. A wide range of surface coatings employs various molecular interactions between dsDNA and magnetic nano-sorbents. However, a reliable, comparative evaluation of their performance is complex. In this work, selected Fe3O4 modifications, i.e., polyethyleneimine, gold, silica, and graphene derivatives, were comprehensively evaluated for applications in dsDNA extraction. A family of single batch nanoparticles was compared in terms of morphology (STEM), composition (ICP-MS/MS and elemental analysis), surface coating (UV-Vis, TGA, FTIR), and MNP charge (ζ-potential). ICP-MS/MS was also used to unify MNPs concentration allowing a reliable assessment of individual coatings on DNA extraction. Moreover, studies on adsorption medium (monovalent vs. divalent ions) and extraction buffer composition were carried out. As a result, essential relationships between nanoparticle coatings and DNA adsorption efficiencies have been noticed. Fe3O4@PEI MNPs turned out to be the most efficient nano sorbents. The optimized composition of the extraction buffer (medium containing 0.1 mM EDTA) helped avoid problems with Fe3+ stripping, which improved the validity of the spectroscopic determination of DNA recovery.

Prodigious therapeutic effects of combining mesenchymal stem cells with magnetic nanoparticles.

Mesenchymal stem cells (MSCs) have gained wide-ranging reputation in the medical research community due to their promising regenerative abilities. MSCs can be isolated from various resources mostly bone marrow, Adipose tissues and Umbilical cord. Huge advances have been achieved in comprehending the possible mechanisms underlying the therapeutic functions of MSCs. Despite the proven role of MSCs in repairing and healing of many disease modalities, many hurdles hinder the transferring of these cells in the clinical settings. Among the most reported problems encountering MSCs therapy in vivo are loss of tracking signal post-transplantation, insufficient migration, homing and engraftment post-infusion, and undesirable differentiation at the site of injury. Magnetic nano particles (MNPs) have been used widely for various biomedical applications. MNPs have a metallic core stabilized by an outer coating material and their ma gnetic properties can be modulated by an external magnetic field. These magnetic properties of MNPs were found to enhance the quality of diagnostic imaging procedures and can be used to create a carrying system for targeted delivery of therapeutic substances mainly drug, genes and stem cells. Several studies highlighted the advantageous outcomes of combining MSCs with MNPs in potentiating their tracking, monitoring, homing, engraftment and differentiation. In this review, we will discuss the role of MNPs in promoting the therapeutic profile of MSCs which may improve the success rate of MSCs transplantation and solve many challenges that delay their clinical applicability.

Fluid flow induced by helical microswimmers in bulk and near walls.

Magnetic nano- and microswimmers provide a powerful platform to study driven colloidal systems in fluidic media and are relevant to futuristic medical technologies requiring precise yet minimally invasive motion control at small scales. Upon the action of a rotating magnetic field, the helical microswimmers rotate and translate, generating flow in the surrounding fluid. In this paper, we study the fluid flow induced by the rotating helices using a combination of experiments, numerical simulations, and theory. The microhelices are actuated either in a fluid bulk or in proximity to the bottom wall using typical microfluidic device setup. We conclude that the mean hydrodynamic flow due to the helix actuation can be closely approximated by a system of rotlets line distributed along the helical axis (i.e., representing the flow due to rotating cylinder) which gets modified close to a wall through appropriate contributions from image multipoles. As the mean flow can be obtained in closed form, this study can be further applied towards modeling of the dynamics in a swarm of driven microswimmers interacting hydrodynamically near a bounding surface.

Ab initio study of nitrogen and boron doped dimers

The first principle calculations have been employed to study the structural, electronic and magnetic properties of gold contacted dimers that are substitutionally doped with boron and nitrogen atoms. Doping of dimers causes size changes, symmetry distortions, induced magnetism and the emergence of states above the Fermi level. Hybridisation of the molecular orbitals of the doped dimers with the states of the monoatomic gold chains leads to level broadening and significant changes in the spin-polarised densities of states. The variations in the obtained total magnetic moments indicate that the considered complexes are highly favourable for further investigations as building blocks of magnetic nano devices. Transmission spectrum of BN doped complexes shows a significant variation with different levels of doping. The I–V characteristics display rectifying behaviour for a controlled amount of doping enabling the dimers to act as molecular rectifiers.

Synthesis of hexahydroquinolines, 5-amino-1,3-diphenyl-1h-pyrazole-4-carbonitrile and 1-aminoalkyl-2-naphthols derivatives using an engineered copper-based nano-magnetic catalyst (Fe3O4@CQD@Si(OEt)(CH2)3NH@CC@Ad@Cu(OAc)2)

In this project, a novel magnetic nano catalyst was used in solvent-free conditions in three different experimental fabrication sections, including the synthesis of hexahydroquinolines, 5-amino-1,3-diphenyl-1H-pyrazole-4-carbonitrile and 1-aminoalkyl-2-naphthols derivatives. Accordingly, in this study, a Carbon Quantum Dot (CQD)-based nanomagnetic catalyst (Fe3O4@CQD@Si(OEt)(CH2)3NH@CC@Ad@Cu(OAc)2) was synthesized, in which the Fe3O4 nanoparticles surface was protected using carbon quantum dots (CQDs) instead of conventional SiO2. The as-synthesized catalyst was characterized using different techniques, including Fourier transform infrared spectroscopy (FT-IR), X-ray powder Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), Energy-Dispersive X-ray spectroscopy (EDX), EDX Elemental Mapping (EDX-Mapping), Thermal Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA), and Vibrating Sample Magnetometer (VSM). The activity of the as-synthesized catalyst was evaluated in the synthesis of hexahydroquinolines, 5-amino-1,3-diphenyl-1H-pyrazole-4-carbonitrile and 1-aminoalkyl-2-naphthols derivatives. The solvent-free condition with low reaction time and high reaction yield is the results of the prepared catalyst. Moreover, the effect of temperature and the amount of the catalyst (optimum reaction condition) were determined using a systematic approach, namely, the Design of Experiment (DoE). How the reaction was triggered by the catalyst was determined by FT-IR analysis.

The Most Recent Discoveries in Heterocyclic Nanoformulations for Targeted Anticancer Therapy.

Every day, new cases of cancer patients whose recovery is delayed by multidrug resistance and chemotherapy side effects are identified, which severely limit treatment options. One of the most recent advances in nanotechnology is the effective usage of nanotechnology as drug carriers for cancer therapy. As a consequence, heterocyclic nanocarriers were put into practice to see whether they could have a better cure with positive results. The potential of a therapeutic agent to meet its desired goal is vital to its success in treating any disease. Heterocyclic moieties are molecules that have a wide variety of chemically therapeutic functions as well as a significant biological activity profile. Heterocyclic nanoformulations play an important role in cell physiology and as possible arbitrators for typical biological reactions, making them valuable in cancer research. As a result, experts are working with heterocyclic nanoformulation to discover alternative approaches to treat cancer. Due to their unique physicochemical properties, heterocyclic compounds are real cornerstones in medicinal chemistry and promising compounds for the future drug delivery system. This review briefly explores the therapeutic relevance of heterocyclic compounds in cancer treatment, various nanoformulation, and actively describes heterocyclic magnetic nano catalysts and heterocyclic moiety, as well as their mode of action, which have favorable anti-cancer effects.

Modeling and Analysis of Magnetic Nanoparticle Biosensor with DNA and Protein Biomarkers

Recent developments in the field of nanotechnology have enabled the invention of nano biosensors that aid in early detection of cancer. With large number of diseases affecting human beings it is mandatory to choose suitable biomarker for disease detection. In this paper, a summary of various biomaterials and sensing technology is discussed. The biosensors that can detect cancers have been summarized with their detection principle. Magnetic nano materials as sensing materials with DNA and protein biomarkers are analyzed for their performances based on the simulation settings in biosensor lab from nanohub.org. Modeling of magnetic nanoparticles and their performances have been evaluated and discussed

Magnetic Self-Healing Composites: Synthesis and Applications.

Magnetic composites and self-healing materials have been drawing much attention in their respective fields of application. Magnetic fillers enable changes in the material properties of objects, in the shapes and structures of objects, and ultimately in the motion and actuation of objects in response to the application of an external field. Self-healing materials possess the ability to repair incurred damage and consequently recover the functional properties during healing. The combination of these two unique features results in important advances in both fields. First, the self-healing ability enables the recovery of the magnetic properties of magnetic composites and structures to extend their service lifetimes in applications such as robotics and biomedicine. Second, magnetic (nano)particles offer many opportunities to improve the healing performance of the resulting self-healing magnetic composites. Magnetic fillers are used for the remote activation of thermal healing through inductive heating and for the closure of large damage by applying an alternating or constant external magnetic field, respectively. Furthermore, hard magnetic particles can be used to permanently magnetize self-healing composites to autonomously re-join severed parts. This paper reviews the synthesis, processing and manufacturing of magnetic self-healing composites for applications in health, robotic actuation, flexible electronics, and many more.

Understanding the Interaction Between Fullerene and Graphene Nanoribbons Using Density Functional Theory

Carbon based heterostructures are extremely important in the field of material science as the junction of two carbon nanomaterials strongly influence the properties of a material. In present work, the structural, electronic and magnetic properties of covalently attached C60 cage with armchair and zigzag GNRs have been investigated using density functional theory. AGNR-nanobuds don't form stable structures, owing to their positive values of the interaction energy. However, pure and N/B doped ZGNR-nanobud form stable structures with [2+2]hhT mode, hence presenting the possibility of their formation. Average diameter for N doped ZGNR-nanobuds decreases as the C-N bond length is lower than the C-C bond length whereas average diameter for doped ZGNR increases due to the large C-B bond length. The considered complexes are magnetic in nature having a finite value of total magnetic moment. Increase in total magnetic moment is due to the induced localized magnetic moments near dopant sites, whereas decrease in the total magnetic moments is due to the reduction in magnetic moments at C-sites near connecting bond atoms. The significant variation in electronic density of states near the Fermi level leads to change in the metallic behaviour of ZGNR-nanobuds. Mulliken charge analysis shows that in N-doped nanobud, there is a transfer of charge from N to surrounding C atoms due to their electronegativity difference, and there is a gain in charge of B from surrounding C atoms. The unique electronic and magnetic properties of nanobuds can lead to the possible applications in the field of magnetic nano devices.

Synthesis of Magnetic Fe3O4 Nano Hollow Spheres for Industrial TNT Wastewater Treatment.

The aim of the present work was to synthesize magnetite (Fe3O4) nano hollow spheres (NHS) via simple, one-pot, template-free, hydrothermal method. The structural, morphological, and surface analysis of Fe3O4 NHS were studied by scanning electron microscopy (SEM), x-ray diffraction technique (XRD), Fourier transform infrared spectroscopy FTIR and burner-Emmett-teller (BET). The as obtained magnetic (Fe3O4) NHS were used as an adsorbent for treating industrial trinitrotoluene (TNT) wastewater to reduce its Chemical Oxygen Demand (COD) values. Adsorption capacity (Qe) of the NHS obtained is 70 mg/g, confirming the attractive forces present between adsorbent (Fe3O4 NHS) and adsorbate (TNT wastewater). COD value of TNT wastewater was reduced to >92% in 2 h at room temperature. The adsorption capacity of Fe3O4 NHS was observed as a function of time, initial concentration, pH, and temperature. The applied Fe3O4 NHS was recovered for reuse by simply manipulating its magnetic properties with slight shift in pH of the solution. A modest decrease in Qe (5.0–15.1%) was observed after each cycle. The novel Fe3O4 NHS could be an excellent candidate for treating wastewater generated by the intermediate processes during cyclonite, cyclotetramethylene-tetranitramine (HMX), nitroglycerin (NG) production and other various environmental pollutants/species.

Magnetic Nanoparticles in Bone Tissue Engineering.

Large bone defects with limited intrinsic regenerative potential represent a major surgical challenge and are associated with a high socio-economic burden and severe reduction in the quality of life. Tissue engineering approaches offer the possibility to induce new functional bone regeneration, with the biomimetic scaffold serving as a bridge to create a microenvironment that enables a regenerative niche at the site of damage. Magnetic nanoparticles have emerged as a potential tool in bone tissue engineering that leverages the inherent magnetism of magnetic nano particles in cellular microenvironments providing direction in enhancing the osteoinductive, osteoconductive and angiogenic properties in the design of scaffolds. There are conflicting opinions and reports on the role of MNPs on these scaffolds, such as the true role of magnetism, the application of external magnetic fields in combination with MNPs, remote delivery of biomechanical stimuli in-vivo and magnetically controlled cell retention or bioactive agent delivery in promoting osteogenesis and angiogenesis. In this review, we focus on the role of magnetic nanoparticles for bone-tissue-engineering applications in both disease modelling and treatment of injuries and disease. We highlight the materials-design pathway from implementation strategy through the selection of materials and fabrication methods to evaluation. We discuss the advances in this field and unmet needs, current challenges in the development of ideal materials for bone-tissue regeneration and emerging strategies in the field.

Flow of magnetic shear thinning nano fluid under zero mass flux and hall current

In this research, the investigation of Hall and ion-slip effects on oblique stagnation point flow of magneto hydrodynamics Casson nanofluid have been discussed with Newtonian heating and zero heat and mass on an elastic surface. The mass concentration equation is also contemplated to examine the flow. By use of proper similarity transformation the governing equation of model are transformed into system of nonlinear ODEs. The numerical results are presented by using the Runge-Kutta (RK) Fehlberg method, accompanied by the shooting technique by converting the system of ODEs to first-order ODEs. The effect of all physical constraints on velocity, temperature, and nanoparticles' concentration is shown graphically. Skin friction quantities, heat and mass flux are the physical quantities which are to be measured numerically. Temperature and concentration of nanoparticles near the wall in negligibly small for magnetic field parameter but this have a dominant influence on temperature and concentration of nanoparticles far away from the surface. Also it is observed that mass flux at the surface is larger for Ion slip parameter and Hall parameter, while skin friction coefficient at surface rises for magnetic field parameter but decreases for Hall parameter.

Microwave assisted ultrafast synthesis of graphene oxide based magnetic nano composite for environmental remediation

We have successfully synthesized multi-layer graphene oxide and graphene oxide based magnetic nanocomposite (M/GO) by microwave-assisted modified Hummers’ method for removal of toxic lead (Pb 2+ ) and cadmium (Cd 2+ ) ions from aqueous solution. The X-ray diffraction spectra of synthesized graphene oxide and M/GO confirm increased interlayer spacing along c-axis. Raman spectra revealed the good quality of synthesized GO and M/GO. The wrinkles were seen in the SEM images of synthesized graphene oxide. The presence of conjugated double bond (C C) and carbonyl (C O) were confirmed by using the UV–Vis spectroscopic spectra. Brunauer–Emmett–Teller (BET) analysis showed high (126 m 2 /g) surface area M/GO composite which accounts for large number of active binding sites for the adsorption of heavy metal ions. The adsorption studies revealed that Pb 2+ ions were efficiently adsorbed on GO sheets. Interestingly, M/GO showed better adsorption for cadmium ions. Addition of stock solution of Pb 2+ and Cd 2+ ions to M/GO solution, removal of M/GO containing Pb 2+ , and Cd 2+ ions using Neodymium magnet.

Low-temperature large-scale hydrothermal synthesis of optically active PEG-200 capped single domain MnFe2O4 nanoparticles

Herein, we report an intrinsic fluorescence in polyethylene glycol (PEG) coated manganese ferrite (MnFe2O4) magnetic nano particles (MNPs). Generally, nano ferrites (NFs) do not show fluorescence characteristics, however, imparting fluorescence in these materials can be valuable for many applications as the stipulation of external control over the properties by external field provides an opportunity to develop active-controlled devices. In the present work, PEG-200 coated MnFe2O4 MNPs have been synthesized by a large-scale, facile one-pot hydrothermal method. The optical properties of MnFe2O4 MNPs have been by photoluminescence (PL) spectroscopy suggest that the prepared sample is showing sharp emission spectra at 422 nm, corresponding to the violet band, and second at 458 nm corresponding to the blue band. The presence of oxygen vacancy created at both tetrahedral and octahedral sites and shallow hole defects are responsible for the PL behavior in the PEG-coated MnFe2O4. The time-resolved PL (TRPL) results suggest that the MnFe2O4 MNPs have two decay times τ1=1.29ns and τ2=6.85ns which are non-correlated and correspond to different defect states. The electronic bandgap of the MNPs is 3 eV obtained from the Tauc plot using UV absorption spectra. Moreover, the structural analysis has been carried out using X-ray diffraction and various optical and magnetic properties have been correlated to structural parameters and cation distribution. The ferromagnetic resonance (FMR) spectra of the MnFe2O4 MNPs sample show a broad single peak which confirms the ferromagnetic characteristics of the sample and the g-value obtained for the sample is 1.98 which suggests that the super exchange interactions (SEI) dominates over the dipolar interaction. The M-H loop confirms the single domain nature of the sample and the saturation magnetization (SM) is 68 emu/g. The obtained value of SM is higher than the previously reported literature due to an increase in the occupancy of Fe3+ and Mn2+ ions at octahedral sites (Neel’s model). Further, the FTIR spectra confirm the spinel phase formation, and the size distribution and average size are obtained using electron microscopy analysis. The intrinsic fluorescent PEG-coated MnFe2O4 are highly suitable for a diverse range of biomedical (bio-imaging, sensing, magnetic resonance imaging (MRI) contrast agent), optoelectronics, and optical applications.

Columnar dipolar clusters defying gravity.

A striking and highly versatile feature of magnetic (nano)particles is their ability to be manipulated at will at a distance by external fields. In this paper, the influence of gravity on the self-assembly of dipolar particles near a surface in the presence of a strong vertical magnetic field is investigated theoretically. A rich ground-state phase diagram stems from the effects of the number of particles N and gravity. Two distinct regimes are discovered for the gravity-mediated breakup of a standing chain. When N is small, there is a chain fragmentation (with two widely separated repulsive chain fragments) above a critical value for the gravity, whereas for higher chains, ribbonization (with two cohesive chain fragments) sets in. In both scenarios, simple algebraic decays for the transition gravity as a function of N are analytically predicted and accurately corroborate the exact numerical results. Further intricate chain fragmentations and internal ribbon transformations operate upon further increasing the gravity until all N constitutive particles lie on the surface. Our findings shed additional light on various recent experiments and computer simulations on magnetic colloids and granular media.

Mechanism enhanced active biochar support magnetic nano zero-valent iron for efficient removal of Cr(VI) from simulated polluted water

This work focused on the use of low-cost magnetic biochar adsorbent prepared from Litchi chinensis peel for the Cr(VI) amelioration through the reduction-adsorption process. This magnetic biochar was prepared by the pyrolysis process, where the nano zerovalent iron (nZVIO) was decorated on the surface of Litchi peel biochar (LPBC). The XRD and TEM studies indicated that the nano-scale zerovalent iron nanoparticles were crystalline having a particle size of 5 ± 0.1 nm. The BET analysis showed the mesoporous nature of the material with good surface area (124 m2/g) and also material has a magnetic saturation value of 0.176 emu/g, where as surface area of LPBC were 325 m2/g and Ms valie 1.1 emu/g respectively. Three factorial Box–Behnken experimental design was simulated for Cr(VI) removal by taking key parameters initial concentration, adsorbent dose, and initial pH as independent factors. The optimum values obtained from desirability function and given by the model were initial Cr(VI) concentration of 5.87 mg/L, 3.14 for pH, and 0.195 g/L for adsorbent dose, which resulted in approximately 95.38% removal of Cr(VI) in these optimum conditions. Langmuir isotherm and pseudo-second-order kinetics data were explained in the adsorption studies. The adsorbent has an adsorption capacity of 98.36 mg/g at the obtained optimized conditions. The thermodynamics study specified a spontaneous process for Cr(VI) removal. The adsorption mechanism was detailed by XPS analysis which indicated a reduction of Cr(VI) to Cr(III) then adsorption of Cr(III) on the adsorbent surface.

Steering the Drug Release of Smart Magnetic Self-Assembled Nano Micelles in an Internal Thoracic Artery Flow for Breast Cancer Therapy

Steering the Drug Release of Smart Magnetic Self-Assembled Nano Micelles in an Internal Thoracic Artery Flow for Breast Cancer Therapy

Розрахунок границь робочої зони круглого магнітного аплікатора

We considered the problem of modeling a magnetic applicator of round shape, designed to act on an object (target) with a constant or variable magnetic field. Due to the fact that the magnetic field monotonically decreases with increasing distance to the applicator, the model includes 3 applicators with different radii, and the problem is solved based on their comparison At the same time, the larger and smaller applicators have radii that are larger or smaller than the radius of the average applicator by the same number of times (scale factor k). Analytical dependences on k of the near, far boundary, and middle of the intermediate zone, i.e., the working zone, in which the target should be located, were found in the approximation of the current loop. Asymptotics were found in extreme cases of minimal (k=1) and large (k>>1) scale factors. It is shown that the middle of the working zone at k=1 is equal to R/√2, (R is the radius of the applicator), and at k>>1 it grows as (R/2) k^(1/3). These results provide a solution to the "direct" problem of choosing target parameters for an applicator of a certain radius - size and distance to it. Such a selection is critical when the targets have a sufficiently large size and the distance to which cannot exceed a certain critical value (depth of occurrence), which takes place in particular for the action by magnetic field on certain organs or the area of localization of magnetic (nano)materials inside biological objects, including humans or animals.

Experimental study on adsorption properties of functional magnetic nano materials for heavy metal pollutants

Experimental study on adsorption properties of functional magnetic nano materials for heavy metal pollutants