Concentration Of Magnetic Nanoparticles Research Articles

Morphology and structure of sawdust waste after adding magnetic nanoparticles

Sengon (Albizia chinensis) is a type of forest plant that grows quickly and is widely used to meet human needs. The large number of uses of Sengon wood causes sengon wood waste, such as sawdust, to increase. The study’s aim is to analyze the morphology and structure of sawdust waste after adding magnetic (Fe3O4) nanoparticles. The methods include collecting sawdust waste from wood (Sengon) was conducted by the crushing process to get smaller sawdust sizes. Alkalization was applied to sawdust and followed by a bleaching process. The powder is then immersed in a solution containing magnetic (Fe3O4) nanoparticles of 10wt%, and then dried. Sawdust composite powder the analyzed using X-ray diffraction and electron microscope instruments. The result indicates that magnetic nanoparticles deposit on sawdust powder and then make the powder become rougher. Higher content of magnetic nanoparticles causes higher agglomeration. The diffraction pattern with 2θ of 14, 16, and 22 indicates that the structure of sawdust is cellulose 1β. The degree of crystalline of sawdust powder reduces from 76.1% to 73.3% after adding magnetic nanoparticle. In the future, these composite powder results will develop as flocculants for wastewater treatment.

Commercial Chip-based Tunneling Magnetoresistance Sensor for Green-synthesized Magnetic Nanoparticles Assay

Owing to their significant roles in multiple sectors, the demand for high-performance, rapid, user-friendly, and low-cost sensors is crucial for biosensing. This paper reports the performance of a commercial chip-based tunneling magnetoresistance (TMR) sensor for detecting green-synthesized magnetic nanoparticles (MNP) as potential magnetic labels. A Simple and low-cost design consisting of a TMR chip ALT-025 integrated with an Arduino microcontroller and a basic differential amplifier was developed to provide real-time and measurable digital readouts. Three kinds of ferrite MNPs (Fe3O4, CoFe2O4 and MnFe2O4) was synthesized by the coprecipitation method on the green synthesis approach utilizing Moringa Oleifera extracts. All sample have a face-centered cubic inverse spinel structure with average grain size of 10.3 nm, 9.2 nm and 6.1 nm for Fe3O4, CoFe2O4 and MnFe2O4, respectively. Furthermore, soft ferromagnetic behavior is identified for all sample with magnetization saturation of 55.3 emu/g, 37.6 emu/g, 19.3 emu/g for Fe3O4, CoFe2O4 and MnFe2O4, respectively. The sensor showed a promising performance in the detection of MNPs. For the three particles, the sensitivity exhibited a linear function of the MNPs concentration. The sensitivity is related not only to the particle size but also to the magnetization of the nanoparticles in the bias field. The change in the output voltage was proportional to the bias magnetization (MBias), indicating that particles with a higher bias magnetization can produce a stronger magnetic stray field on the TMR sensor surface. The sensor system successfully detected MNPs at different stray field intensities. Furthermore, a low limit of detection was achieved using these methods. Moreover, the remarkable stability and repeatability of the sensor is further validated by the steady signal acquired for 30s with an RSD of 0.5-28.5%. Therefore, the integration of commercial chip-based TMR sensors and green-synthesized MNPs has great potential for advancing the detection of various biomolecules.

Comprehensive analysis of effects of magnetic nanoparticles on aerobic granulation and microbial community composition: From the perspective of acyl-homoserine lactones mediated communication

As dosing additives benefit for aerobic granular sludge (AGS) cultivation, effects of different concentrations (0, 10, 50 and 100 mg/L) of magnetic nanoparticles (Fe3O4 NPs) on aerobic granulation, contaminant removal and potential microbial community evolution related to acyl-homoserine lactones (AHLs) mediated bacterial communication were investigated with municipal wastewater. Results showed that the required time to achieve granulation ratio > 70 % was reduced by 60, 90 and 30 days in phase II with addition of 10, 50, 100 mg/L Fe3O4 NPs, respectively. 50 mg/L Fe3O4 NPs can improve contaminant removal efficiency. The promotion of relative abundance of AHLs-producing and AHLs-producing/quenching populations and AHLs-related functional genes accompanied with faster granulation. Iron-cycling-related bacteria were closely related with AHLs-related bacteria during AGS formation. Co-occurrence network analyses showed that AHLs-mediated communication may play an important role in coordinating microbial community composition and functional bacteria participating in nitrogen and polyphosphate metabolisms during aerobic granulation process.

Effects of enclosure shape on MHD nanofluid flow and irreversibility in different shaped systems under fluid volume constraint

PurposeThe purpose of this study is to investigate the influence of enclosure shape on magnetohydrodynamic (MHD) nanofluidic flow, heat transfer and irreversibility in square, trapezoidal and triangular thermal systems under fluid volume constraints, with the aim of optimizing thermal behavior in diverse applications.Design/methodology/approachThe study uses numerical simulations based on a finite element-based technique to analyze the effects of the Rayleigh number (Ra), Hartmann number (Ha), magnetic field orientation (γ) and nanoparticle concentration (ζ) on heat transfer characteristics and thermodynamic entropy production.FindingsThe key findings reveal that the geometrical design significantly influences fluid velocity, heat transfer and irreversibility. Trapezoidal thermal systems outperform square systems, while triangular systems achieve optimal enhancement. Nanoparticle concentration enhances heat transfer and flow strength at higher Rayleigh numbers. The magnetic field intensity has a significant impact on fluid flow and heat transport in natural convection, with higher Hartmann numbers resulting in reduced flow strength and heat transfer. The study also highlights the influence of various parameters on thermodynamic entropy production.Research limitations/implicationsFurther research can explore additional geometries, parameters and boundary conditions to expand the understanding of enclosure shape effects on MHD nanofluidic flow and heat transfer. Experimental validation can complement the numerical simulations presented in this study.Originality/valueThis study provides valuable insights into the impact of enclosure shape on heat transfer performance in MHD nanofluid flow systems. The findings contribute to the optimization of thermal behavior in applications such as electronics cooling and energy systems. The comparison of different enclosure shapes and the analysis of thermodynamic entropy production add novelty to the study.

Fabrication and characterization of magnesium implants coated with magnetic nanoparticles-wollastonite-hydroxyapatite for medical and sports injury applications: Finite element analysis

Recently, wollastonite nanoceramics were considered a suitable choice for the orthopedic applications in terms of the presence of silicon, and calcium ions. Using the nanoceramics for the coatings of orthopedic application was increased to facilitate the possibility of stabilization and integration with the host tissue and the regeneration of bone tissues. Using the ceramic coatings was extensively improved due to their biological properties. The present investigation delves into the utilization of innovative wollastonite nanoceramics (WS) fortified with magnetite nanoparticles (MNPs) as coatings for biomechanical implants. The study focuses on evaluating the bioactivity and mechanical attributes of electrophoretic coatings while characterizing their phase and structure through the employment of X-ray diffraction (XRD) and scanning electron microscope (SEM). The coatings are also evaluated for bioactivity and biodegradation in simulated body fluid (SBF) and phosphate-buffered saline (PBS) for 21 days. Additionally, the mechanical properties of the coatings are simulated using Finite Element Analysis (FEA) to predict porosity and elastic modulus. The presence of wollastonite with silica nanoparticles in a magnesium alloy significantly enhances bone formation, as evidenced by the highest degree of apatite formation observed in the alloy containing 10% wollastonite. This particular composition resulted in a remarkable 29% increase in apatite growth. These findings highlight the potential of incorporating wollastonite with silica nanoparticles to promote and improve bone formation processes. The results indicate that the specimen coated with a 10% concentration of magnetic nanoparticles (MNPs) exhibits favorable mechanical performance and desirable biological behavior, making it suitable for use in sports biomechanics implants. The results indicate that the specimen treated with a greater concentration of MNPs demonstrates advantageous mechanical characteristics and desirable biological responses, rendering it a promising candidate for the production of sports and orthopedic prostheses.

Impact of thermal radiations, heat generation/absorption and porosity on MHD nanofluid flow towards an inclined stretching surface: Non‐similar analysis

AbstractObjective of this investigation is to provide a novel study of the flow of a magnetohydrodynamics (MHD) nanofluid over an inclined stretching surface in a permeable medium in a 2‐dimensional boundary layer. The convection model further incorporates heat radiation and heat sources/sinks. Nanomaterials include magnesium oxide and copper oxide . Using non‐similarity transformations, the set of governing equations is transformed into a set of dimensionless partial differential equations (PDEs). Using the local non‐similarity technique, the resulting system of dimensionless PDEs is treated as a set of ordinary differential equations (ODEs), and then solved with the help of the bvp4c MATLAB tools. This comprehensive research involves a thorough investigation of the significant starting physical characteristics and their impacts on the velocity and nanofluid temperature profiles. These profiles are shown using a set of graphical representations and numerical tables. It is worth noting that changes in the magnetic and porosity parameters result in a decrease in the velocity profile, but the Grashof number exhibits a reciprocal correlation. When we account for the effects of the Eckert number and the radiation parameters in a given flow regime, we also see an increase in the nanofluid's temperature profile. It has been shown that when the magnetic number and the Eckert number are augmented, the heat transmission rate decreases. The skin friction coefficient grows on a logarithmic scale when magnetic parameters and nanoparticle concentration are increased in estimation. The numerical calculations are checked for accuracy by comparing them to previously published findings, which guarantees an exact match in a constrained setting. Scientists investigating nanomaterials and their applications in manufacturing and thermal engineering may find this research instructive.

Inclusion of CoFe2O4 ultrafine nanoparticles in 7CB liquid crystal: effects on temperature-dependent magnetic properties and insights for expanding the application of LC systems in hyperthermia treatments

ABSTRACT This work presents a comprehensive analysis of the magnetic properties of pristine and citric acid-coated cobalt ferrite ( CoF e 2 O 4 ) nanoparticles (NPs) dispersed in the host nematic 4 ′ -heptyl-4-biphenylcarbonnitrile (7CB) system. Our results shed light on the promising potential of combining liquid crystals (LC) with magnetic nanoparticles for cancer treatment. This opens up exciting avenues for further exploration and possible applications in the field of oncology. The study focuses on examining the magnetic behaviour of LC dispersed systems with two concentrations of magnetic nanoparticles (0.03 and 0.04 wt%). Notably, intriguing temperature-dependent magnetisation plots reveal a distinctive cusp, which can be attributed to the freezing phenomenon of the liquid crystal. This observation offers valuable insights into the system's magnetic properties and interactions, deepening our understanding of its behavior.

Fabrication and characterization of magnetic cobalt ferrite intercalated chitosan grafted polyaniline ternary nanocomposites for removing some heavy metals simultaneously

Chitosan grafted polyaniline (Ch-g-PANI) loaded with different concentrations of cobalt ferrite magnetic (CoFM) nanoparticles (2, 5 and 10 wt%) to form (Ch-g-PANI/CoFM) nanocomposites were fabricated. X-ray diffraction (XRD), High-Resolution Transmission Electron Microscope (HRTEM), Scanning Electron Microscope (SEM), Energy-Dispersive X-ray (EDX), Fourier transform inferred (FT-IR), and Vibrating Sample Magnetometer (VSM) were carried out to investigate the structure, morphology, chemical composition, and magnetic properties of Ch-g-PANI and Ch-g-PANI/CoFM) nanocomposites. Adsorption performance of these prepared samples towards heavy metals (Pb2+, Cu2+, Fe3+, Cd2+, Li1+, Co2+, Al3+, Mn2+, Zn2+, Ni2+, Cr2+, and V2+) was investigated. The effects of CoFM NPs concentraion doped in grafted polymer, initial metal concentration, temperature, pH, and contact time on heavy metal removal efficiency were optimized. SEM revealed abundant pores for optimum sample that enhance the heavy metal removal efficiency. Competitive adsorption tests proved that Ch-g-PANI/CoFM5 NPs showed higher efficiency for tested heavy metals. The removal efficacy of optimum sample (Ch-g-PANI/CoFM5) reached maximum values 98, 95.3, 96, 99.2, 97, 99.9, 88, 94.4, 99.8, 93.4, 98.96, 93, and 93.9 % for Pb2+, Cu2+, Fe3+, Cd2+, Li1+, Co2+, Al3+, Mn2+, Zn2+, Ni2+, Cr2+, and V2+, respectively at 90 min(equilibrium time), the element ions concentration of 10 mg/L and pH range of 4–6 depending on the kind of metal ions. Freundlich model is the best isotherm model for the equilibrium data, suggesting the multilayer adsorption on the heterogeneous surface. The kinetic data specified that the pseudo-first-order model fitted the adsorption of heavy metal ions on Ch-g-PANI/CoFM5. Thermodynamic studies elucidated the feasible, spontaneous, random, and endothermic adsorption. From an economic viewpoint, the regeneration study implied that the optimal sample Ch-g-PANI/CoFM5 was efficiently recovered up to four successive cycles.

Evaluation of Magnetic Hyperthermia Efficiency of PEG-Coated Fe3O4 Nanoparticles

Magnetic nanoparticle hyperthermia has drawn considerable interest in cancer therapy. In this study, we report the synthesis of PEG-coated Fe3O4 nanoparticles and evaluate their suitability for magnetic hyperthermia applications. Fe3O4 nanoparticles were synthesized by the chemical coprecipitation method, which are coated with polyethylene glycol (PEG). PEG-coated Fe3O4 nanoparticles were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), dynamic light scattering (DLS) and transmission electron microscopy (TEM). Synthesized nanoparticles possess inverse-spinel structural with a crystallite size of 9.1[Formula: see text]nm. From the M-H hysteresis loops, it was confirmed that the synthesized Fe3O4 nanoparticles were superparamagnetic. The physical size of bare Fe3O4 nanoparticles, as determined from the HR-TEM, is [Formula: see text][Formula: see text]nm, and the corresponding hydrodynamic size of PEG-coated Fe3O4 nanoparticles is [Formula: see text][Formula: see text]nm. Magnetic hyperthermia efficiency of PEG-coated Fe3O4 nanoparticles was determined as a function of magnetic field frequency (162–935.6[Formula: see text]kHz), field strength (5–12[Formula: see text]mT) and nanoparticle concentration (1–100[Formula: see text]mg/mL). Temperature rise in an aqueous dispersion of PEG-coated Fe3O4 nanoparticles was measured for 20[Formula: see text]min. The specific loss power (SLP) was calculated by the corrected slope method. SLP values of PEG-coated Fe3O4 nanoparticles increase with magnetic field frequency and field strength and decrease with nanoparticle concentration. The optimum hyperthermia performance of PEG-coated Fe3O4 nanoparticles was observed for 935.6[Formula: see text]kHz frequency, 10[Formula: see text]mT field strength and 25[Formula: see text]mg/mL concentration. Under these conditions, the measured SLP of PEG-coated Fe3O4 nanoparticles was 4.43[Formula: see text]W/g. These results show that the synthesized PEG-coated Fe3O4 nanoparticles could be a potential candidate for magnetic hyperthermia treatment of cancer.

Study of the calorimetric effect in ferrogels subjected to the high-frequency rotating magnetic field

This study investigates the calorimetric effect in iron oxide-containing ferrogels when exposed to a high-frequency rotating magnetic field. The primary heat generation mechanisms were magnetic relaxation (Néel and Brownian) and magnetic hysteresis. Temperature was monitored over time for various magnetic field amplitudes, enabling the determination of the contributions of both heat release mechanisms as a function of particle concentration and field strength. Experiments were performed using agar-based tissue mimicking phantoms with magnetic nanoparticle weight concentrations ranging from 5 % to 20 %. The magnetic fields applied varied from 1 kA/m to 5 kA/m, with the equipment having a capability of up to 7.5 kA/m at a frequency of 200 kHz. The experimental setup employed a two-phase magnetic system enclosed in an external core where magnetizing coils and parallel connected inductors and capacitors generated spatially and phase shifted fluxes by 90 degrees, resulting in a constant amplitude of rotating magnetic field.The heating efficiency of the rotating magnetic field was found to be approximately twice as effective as an equivalent alternating field in the experiments. The specific loss power exhibited a decreasing trend with the increase in magnetic nanoparticle concentration and the decrease in magnetic field strength. Specifically, as the magnetic nanoparticle concentration increased from 5 % to 20 %, the SLP diminished from 457.3 mW/g (at 5 % concentration and 5 kA/m) to 1.24 mW/g (at 20 % concentration and 1 kA/m). This decrease in SLP can be attributed to enhanced dipole–dipole interactions between particles at smaller interparticle distances as concentration increases, as well as reduced magnetic responsiveness to weaker magnetic fields. Even though Brownian relaxation was likely hindered in the gel structure due to the immobilization of magnetic nanoparticles, the observed magnetic heating effect remains significant. Given the limited existing data on rotating magnetic field effects on tissue mimicking ferrogels, this study offers novel insights, potentially aiding in the optimization of magnetic hyperthermia treatments while highlighting the benefits of rotating over alternating magnetic fields.

Enhanced detection of Listeria monocytogenes using tetraethylenepentamine-functionalized magnetic nanoparticles and LAMP-CRISPR/Cas12a-based biosensor

BackgroundListeria monocytogenes is a pathogenic bacterium that can lead to severe illnesses, especially among vulnerable populations. Therefore, the development of rapid and sensitive detection methods is vital to prevent and manage foodborne diseases. In this study, we used tetraethylenepentamine (TEPA)-functionalized magnetic nanoparticles (MNPs) and a loop-mediated isothermal amplification (LAMP)-based CRISPR/Cas12a-based biosensor to concentrate and detect, respectively, L. monocytogenes. LAMP enables DNA amplification at a constant temperature, providing a highly suitable approach for point-of-care testing (POCT). The ability of CRISPR/Cas12a to cleave ssDNA reporter, coupled with TEPA-functionalized MNPs effective attachment to negatively charged bacteria, forms a promising biosensor. ResultsThe LAMP assay was meticulously developed by selecting specific primers and designing crRNA sequences targeting a specific region within the hly gene of L. monocytogenes. We selected primer and refined the amplification conditions by systematically exploring a temperature range from 59 °C to 69 °C, ensuring the attainment of optimal performance. This process was complemented by systematic optimization of LAMP-CRISPR/Cas12a system parameters. In particular, we successfully established the optimal ssDNA reporter concentrations (0–1.2 μM) and Cas12a-mediated trans-cleavage times (0–20 min), crucial components that underpin the effectiveness of the LAMP-CRISPR/Cas12a-based biosensor. For optimizing parameters in capturing L. monocytogenes using TEPA-functionalized MNPs, capture efficiency was significantly enhanced through adjustments in TEPA-functionalized MNPs concentration, incubation times, and magnetic separation duration. Large-volume (20 mL) magnetic separation exhibited a 10-fold sensitivity improvement over conventional methods. Utilizing TEPA-functionalized MNPs, the LAMP-CRISPR/Cas12a-based biosensor achieved detection limits of 100 CFU mL−1 in pure cultures and 100 CFU g−1 in enoki mushrooms. SignificanceThe integration of this novel technique with the LAMP-CRISPR/Cas12a-based biosensor enhances the accuracy and sensitivity of L. monocytogenes detection in foods, and it can be a promising biosensor for POCT. The 10-fold increase in sensitivity compared to conventional methods makes this approach a groundbreaking advancement in pathogenic bacteria detection for food safety and public health.

Temperature‐Sensitive Properties and Mechanism of Smart Magnetic Fluids Modified with Cellulose Derivatives

AbstractCombining magnetic materials with environmentally sensitive polymers to develop intelligent magnetic fluids that respond to external stimuli has become a new research hotspot. At present, the bottlenecks in the development of temperature‐sensitive materials are the complex composition, and its properties in different laboratories vary greatly. Moreover, despite extensive research on magnetic fluids, there remains a dearth of systematic investigation into temperature‐sensitive intelligent magnetic fluids. In this study, we utilized a UV‐visible spectrophotometer to measure the change in transmittance of different magnetic fluid solutions with temperature variation. We systematically investigated the effects of the magnetic fluid dispersion medium, size and concentration of magnetic nanoparticles, type and viscosity of cellulose on the temperature sensitivity of the magnetic fluid. We found that compared with Hydroxypropyl Methyl Cellulose (HPMC) (type I), HPMC (type II) modified magnetic fluid has better stability and a higher phase transition temperature. Moreover, with the increase of the concentration of magnetic fluid, the phase transition temperature is higher. In addition, the lower the viscosity of HPMC‐modified magnetic fluid, the better the stability and the higher the phase transition temperature. We also studied the mechanism of temperature sensitivity, and the results showed that hydrogen bond interactions play an important role. This research will facilitate the use of temperature‐sensitive smart magnetic fluids for biomedical application.

Exploiting the Potential of Magnetic Nanoparticles for Rapid Diagnosis Tests (RDTs): Nanoparticle-Antibody Conjugates and Color Development Strategies.

Magnetic nanoparticles (MNPs) have emerged as a promising material in disease diagnostics due to their potential to enhance detection sensitivity, facilitate concentration and purification of target substances in diverse samples, and enable favorable color-based detection. In this study, antibody-conjugated MNPs were successfully synthesized and validated through two appropriate methods: the measurement of MNPs' size and the use of phosphatase methods. Additionally, three methods were suggested and implemented for developing color in MNPs-based immunoassay, including the formation of MNP aggregations, utilization of MNPs' peroxidase-like activity, and synthesis of dually-conjugated MNPs with both enzyme and antibody. In particular, color development utilizing nanoparticle aggregations was demonstrated to result in a more yellowish color as virus concentration increased, while the peroxidase activity of MNPs exhibited a proportional increase in color intensity as the MNP concentration increased. This observation suggests the potential applicability of quantitative analysis using these methods. Furthermore, effective concentration and purification of target substances were demonstrated through the collection of MNPs using an external magnetic field, irrespective of factors such as antibody conjugation, dispersion medium, or virus binding. Finally, based on the key findings of this study, a design proposal for MNPs-based immunoassay is presented. Overall, MNPs-based immunoassays hold significant potential for advancing disease diagnostics.

Modular Droplet‐Based Fluidics for Large Volume Libraries of Individual Multiparametric Codes in Lab‐On‐Chip Systems

AbstractDroplet‐based lab‐on‐a‐chip systems offer vast possibilities in the manipulation, guidance, tracking, and labeling of individual droplet‐based bioreactors. One of the targeted application scenarios is in drug discovery where millions of unique codes are required, which is out of reach for current technologies. Here, a concept for the realization of multiparametric codes, where information is stored in distinct physical and chemical parameters, is proposed and validated. Exemplarily, the focus is on the use of impedance and magnetic sensing by monitoring ionic concentration as well as magnetic content per droplet and droplet volume. Codes based on aqueous ferrofluid droplets are prepared using a tubing‐based millifluidic setup and consist of up to six droplets of different combinations of volumes and magnetic concentration. It is demonstrated that a droplet chain of three single droplets of different volumes with nine different magnetic nanoparticle concentrations accompanied with four different ionic concentrations per droplet offers up to 3 million unique codes. The developed fluidic platform can be readily extended to other types of sensors including optical ones to boost the coding capacity even further.

Magnetic open porous microspheres via high internal phase emulsion templating as efficient Pb adsorption material

Emulsion templating enables the synthesis of hierarchically porous polymers. By adding another phase to this process and therefore, creating a multiple emulsion templating method, it is possible to synthesise hierarchically porous microspheres. In this study water-in-oil-in-water double emulsion templating was used to prepare porous microspheres by utilising thiol-ene click chemistry. For this trimethylolpropane tris(3-mercaptopropionate) and trimethylolpropane triacrylate were used. To the monomer phase magnetic nanoparticles were added to synthesise polyHIPE microspheres with magnetic properties. The higher magnetic nanoparticles (MNPs) content also affected the morphology and microsphere size. With increasing MNPs content the bead diameter decreased, while the diameter of the primary pores of the cross-section increased. However, while the MNPs influenced the morphology, the chemical composition was not influenced. The microspheres were used for the removal of Pb2+. From a 2.9 mg/L solution up to 97.0% of Pb was removed after 24 h.

Analysis of unsteady non-Newtonian Jeffrey blood flow and transport of magnetic nanoparticles through an inclined porous artery with stenosis using the time fractional derivative

In the present study, a Caputo–Fabrizio (C–F) time-fractional derivative is introduced to the governing equations to present the flow of blood and the transport of magnetic nanoparticles (MNPs) through an inclined porous artery with mild stenosis. The rheology of blood is defined by the non-Newtonian visco-elastic Jeffrey fluid. The transport of MNPs is used as a drug delivery application for cardiovascular disorder therapy. The momentum and transport equations are solved analytically by using the Laplace transform and the finite Hankel transform along with their inverses, and the solutions are presented in the form of Laplace convolutions. To display the solutions graphically, the Laplace convolutions are solved using the numerical integration technique. The study presents the impacts of different governing parameters on blood and MNP velocities, volumetric flow rate, flow resistance, and skin friction. The study demonstrates that blood and MNP velocities boost with an increase in the fractional order parameter, Darcy number, and Jeffrey fluid parameter. The volumetric flow rate decreases and flow resistance increases with enhancement in stenosis height. The non-symmetric shape of stenosis and the rheology of blood decrease skin friction, whereas enhancement in MNP concentration increases skin friction. A comparison of the present result with the previous work shows excellent agreement. The present study will be beneficial for the field of medical science to further study atherosclerosis therapy and other similar disorders.

PEROXIDASE-LIKE ACTIVITY OF MAGNETIC NANOPARTICLES IN THE PRESENCE OF BLOOD PROTEINS

The generation of hydroxyl radicals from hydrogen peroxide in aqueous solutions containing magnetic nanoparticles (MNPs), hemoglobin (Hb), immunoglobulin G (IgG), and human serum albumin (HSA) has been determined. The dependence of the rate of formation of the oxidized product of o-phenylenediamine (o-PDA) on the concentration of MNPs in solution, as well as on the concentration of proteins, was obtained. The peroxidase-like activity of MNPs was shown to decrease in the presence of HSA and IgG, while the addition of Hb to the reaction mixture was leading to its decrease and increase depending on protein concentration. The obtained effects can be used in the development of systems based on MNPs for theranostics, in particular, for suppression of tumor growth, and in predicting the ability of particles to catalyze the generation of reactive oxygen species (ROS) in vivo.

Preparation of graphene oxide enhanced magnetic composite hydrogels by one‐pot method for selective adsorption

AbstractMagnetic composite hydrogels exhibit promising prospects for diverse applications, but their mechanical properties impose limitations on their further advancement. In this study, a novel approach is proposed to directly prepare magnetic composite hydrogels utilizing nanoferroferric oxide, aiming to replace the existing preparation method. Meanwhile, graphene oxide (GO) is introduced into magnetic composite hydrogels to enhance their mechanical characteristics. By employing ammonium citrate (AC) as a dispersant, the dispersion of ferroferric oxide magnetic nanoparticles at a concentration of 40 mg/mL is achieved, enabling their coexistence with GO for the preparation of magnetic composite hydrogels. Notably, the incorporation of 3 mg/mL GO and 40 mg/mL magnetic nanoparticles in polyacrylamide (PAM) hydrogel yields remarkable improvements in maximum stress and strain, reaching 148 kPa and 496%, respectively. In contrast, magnetic composite hydrogels without GO exhibit lower values of 46.5 kPa and 351%. The presence of magnetic nanoparticles imparts magnetism to the hydrogel, with higher concentrations of magnetic nanoparticles leading to increased magnetism. Moreover, the presence of AC and GO renders the hydrogels electronegative, thereby endowing them with selective adsorption capabilities. In summary, the magnetic composite hydrogels prepared by one‐pot method have good mechanical properties and selective adsorption capacity, and have good application potential.

A threefold increase in SAR performance for magnetic hyperthermia by compositional tuning in zinc-substituted iron oxide superparamagnetic nanoparticles with superior biocompatibility

In this work, we report a ultrahigh specific absorption rate (SAR) performance in Zn-substituted magnetite superparamagnetic (SPM) nanoparticles (NPs) for potential application in magnetic hyperthermia (MHT)-based cancer treatment. Although MHT shows promise in cancer therapy, challenges such as low heating performance, agglomeration of magnetic nanoparticles (MNPs) in blood veins, cytotoxicity, and hemocompatibility have hindered clinical uses. To overcome these challenges, we adopted a reverse-micelles based coprecipitation synthesis approach to prevent MNPs agglomeration and optimized the substitution of Zn ions in magnetite to enhance heating performance. Calorimetric measurements showed SAR values of 118 W/g and 181 W/g for magnetite NPs using the initial slope method (ISM) and Box Lucas method (BLM), respectively. Through our compositional optimizations, we achieved a significant increase in SAR value by consciously substituting Zn2+ ions in the magnetite lattice. Specifically, we obtained SAR values of 325 W/g and 579 W/g (>300% increase) for Zn0.3Fe2.7O4 MNPs using ISM and BLM, respectively. This enhancement can be attributed to improved saturation magnetization (174–257 kA/m) and magneto-crystalline anisotropy (12–24 kJ/m3). The increase in saturation magnetization in the magnetite MNPs can be explained by the higher magnetic moment resulting from increased Zn concentration up to ZnxFe3-xO4(x = 0.3), strengthening the JAB interaction. However, further increases in Zn concentration lead to a decrease in saturation magnetization due to non-collinearity, as described by the Yafet-Kittle model. Our optimized MNPs exhibit improved heating performance, enabling the use of lower MNPs concentrations for cancer treatment, reducing potential toxicity effects. Biocompatibility investigations demonstrated a low hemolysis rate (<5%) in a hemolysis assay with red blood cells and high cytocompatibility (>92% cell viability) in MTT assays for all compositions, confirming their potential suitability for clinical applications. This study offers a promising approach to enhance SAR performance, addressing MHT-based cancer treatment challenges, and improving clinical suitability.

Development of a Microfluidic Chip System with Giant Magnetoresistance Sensor for High-Sensitivity Detection of Magnetic Nanoparticles in Biomedical Applications.

Magnetic nanoparticles (MNPs) have been widely utilized in the biomedical field for numerous years, offering several advantages such as exceptional biocompatibility and diverse applications in biology. However, the existing methods for quantifying magnetic labeled sample assays are scarce. This research presents a novel approach by developing a microfluidic chip system embedded with a giant magnetoresistance (GMR) sensor. The system successfully detects low concentrations of MNPs with magnetic particle velocities of 20 mm/s. The stray field generated by the magnetic subject flowing through the microchannel above the GMR sensor causes variations in the signals. The sensor's output signals are appropriately amplified, filtered, and processed to provide valuable indications. The integration of the GMR microfluidic chip system demonstrates notable attributes, including affordability, speed, and user-friendly operation. Moreover, it exhibits a high detection sensitivity of 10 μg/μL for MNPs, achieved through optimizing the vertical magnetic field to 100 Oe and the horizontal magnetic field to 2 Oe. Additionally, the study examines magnetic labeled RAW264.7 cells. This quantitative detection of magnetic nanoparticles can have applications in DNA concentration detection, protein concentration detection, and other promising areas of research.