Search Results (1,019)

Repairing maxillofacial bone defects remains a major clinical challenge due to inadequate vascularisation and poor integration with host tissue. While bioactive scaffolds have shown promise in supporting osteogenesis and angiogenesis, achieving robust and synchronised dual regenerative outcomes is still elusive. This study presents a multifunctional, cell-free magnetic hydrogel platform designed to biomimetically coordinate osteogenic and angiogenic processes for effective maxillofacial bone regeneration. The composite poly(vinyl alcohol)-vaterite (PVA-Vat) hydrogel scaffold incorporates tuneable magnetic nanoparticles (MNPs) composed of single-domain superparamagnetic iron oxide (Fe₃O₄). By harnessing magneto-mechanical cues to orchestrate bilateral communication between human bone mesenchymal stem cells and endothelial cells, this platform provides a deeper mechanistic understanding of coupled tissue regeneration and delivers superior dual-regenerative performance for maxillofacial bone repair. Under magnetic stimulation, a coculture system demonstrated strong osteogenesis-angiogenesis coupling mediated by reciprocal VEGFA-BMP2 signalling. This reciprocal crosstalk was evidenced by a synergistic amplification of VEGFA and BMP2 expression in coculture compared to monocultures, where MNP-stimulated osteoprogenitors secreted VEGFA to drive endothelial capillary-like network formation, while endothelial cells reciprocally enhanced endogenous BMP2 levels to accelerate osteoblastic mineralisation. These findings establish MNP-integrated hydrogels as a cell-free, multifunctional platform capable of synchronising dual regenerative pathways, offering a biomimetic strategy to overcome vascularisation and integration barriers in maxillofacial bone repair. Full article

As the demand for digital storage capacity continues to grow, bit-patterned magnetic recording (BPMR) has emerged as a promising technology to overcome the superparamagnetic limit of conventional recording methods. Nevertheless, the extremely close spacing of magnetic islands in BPMR can result in significant signal corruption, particularly due to inter-track interference. This paper presents robust signal-processing schemes for a two-reader, three-track detection system in a staggered BPMR configuration to address these challenges. The first proposed method employs a sum-soft-information technique, which combines log-likelihood ratios from two detectors to maximize mutual information. This approach significantly improves the reliability of middle-track detection. We also propose the inter-track interference subtraction technique, in which the highly reliable data recovered from the middle track are used to reconstruct the interference signal, which is then subtracted from the upper and lower tracks using an optimized weighting factor. Simulation results at an areal density of 3.0 Tb/in² demonstrate that an optimized weighting factor of 1.78 effectively cancels interference. Moreover, the results indicate that our proposed scheme achieves a bit-error rate (BER) comparable to that of the three-reader, one-track detection BPMR systems. Furthermore, our method also demonstrates a lower BER for both adjacent tracks when compared to the conventional single-reader, two-track reading system, even in the presence of 10% media noise. Full article

Magnetic nanoparticles represent the next-generation drug delivery systems, enabling drug targeting to specific organs without adverse effects on the body and with a controlled release rate. Their strengths are represented by biocompatibility, low cost, and easy drug loading; some drawbacks are aggregation and poor stability in biological media. In the present work, we synthesized magnetic core–shell structures with a magnetite core coated with layered double hydroxides (LDHs) based on Mg²⁺ or Zn²⁺ and Al³⁺ ions and loaded with meloxicam, a poorly water-soluble anti-inflammatory drug. Several syntheses have been attempted to obtain iron oxides based on the only magnetite phase. The combined use of different characterization techniques allowed us to reveal that the best product, showing the crucial room temperature superparamagnetism and a good level of compositional uniformity, was obtained from co-precipitation in nitrogen flow. The next LDH coating was successful, even if the hybrids showed the occurrence of aggregation. The drug was mainly adsorbed onto the LDH surfaces, as shown by the X-ray diffraction and Infrared Spectroscopy techniques. The loaded meloxicam amount was low, but the subsequent release into simulated body fluid could be prolonged for 4 days. Our study provides a proof of concept about the importance of a thorough characterization of the nanocomposite hybrids and their possible use for tricky drugs, such as those of class II of the Biopharmaceutical Classification System. Full article

Background/Objectives: Jaw osteomyelitis (OM) is a refractory purulent inflammation caused by bacterial infection, characterized by persistent infection, excessive bone resorption, and resultant bone defects. Currently, mainstream therapies for jaw OM struggle to eradicate persistent infections, avoid antibiotic resistance, and repair infected bone defects, posing a critical challenge in clinical practice. Methods: Herein, the Fe₃O₄@ZIF-8 core–shell nanoparticles (NPs) platform designed for jaw OM treatment consisted of Fe₃O₄ as the core and zeolitic imidazolate framework-8 (ZIF-8) as the shell. Results: The core–shell platform not only integrated the pH-responsive degradation capability of ZIF-8 but also retained the superparamagnetism of Fe₃O₄ NPs. In the acidic, infectious microenvironment, Fe₃O₄@ZIF-8 NPs underwent continuous degradation, releasing Zn²⁺, thereby conferring potent antibacterial activity. The specific antibacterial mechanism of the nanoparticles lies in the fact that high concentrations of Zn²⁺ directly disrupted bacterial cell membranes and inhibited the bacterial heat shock response. This dysregulates bacterial proteostasis, rendering the bacteria more sensitive to external adverse stresses, ultimately leading to bacterial death. With ZIF-8 framework degradation, the encapsulated Fe₃O₄ NPs were released. Under static magnetic field (SMF) synergy, Fe₃O₄ NPs collaborated with Zn²⁺ to promote bone regeneration and repair infected bone defects in jaw OM lesions. Conclusions: As a multifunctional core–shell platform, Fe₃O₄@ZIF-8 NPs meet the dual clinical needs of antibiosis and osteogenesis, offering a promising translational strategy for jaw OM therapy. Full article

In this study, representative soil profiles developed on clastic rock parent materials in Yunnan Province were investigated to elucidate the formation mechanisms of soil magnetic properties under weakly magnetic parent material conditions and to evaluate the response of magnetic enhancement to chemical weathering and pedogenic differentiation. A combination of environmental magnetic measurements, bulk geochemical analyses, weathering index calculations, and ternary diagram discrimination was applied to characterize soil magnetic behavior, magnetic grain size distribution, and chemical weathering processes. The results show that the clastic rock parent materials exhibit overall low magnetic intensities, with low-frequency magnetic susceptibility (χ_lf) ranging from 2.543 × 10⁻⁸ m³/kg to 595.652 × 10⁻⁸ m³/kg. Under this weakly magnetic background, soils in the study area display pronounced pedogenic magnetic enhancement, with magnetic parameters showing clear and systematic vertical differentiation along soil profiles, indicating that soil magnetic signals are primarily controlled by pedogenesis. The frequency-dependent susceptibility (χ_fd%) generally falls within the range of 5.403%–17.574%, with a mean value of 12.898%, suggesting a substantial contribution from fine-grained magnetic particles. Magnetic grain size diagnostics further indicate that newly formed superparamagnetic (SP) and stable single-domain (SSD) particles generated during pedogenesis dominate the magnetic enhancement signal. The results of the Chemical Index of Alteration (CIA) indicate that approximately 78% of the profiles reach the strong weathering category (CIA > 85), while only 22% fall into the moderate weathering category (CIA: 65–85). Correlation analyses further reveal that grain-size-sensitive magnetic ratios (e.g., χ_fd%, χ_ARM/SIRM) exhibit a strong correspondence with chemical weathering intensity indicators. These findings suggest that, under weakly magnetic parent material conditions, pedogenically induced magnetic enhancement can be more readily identified and quantitatively assessed. The integration of environmental magnetism and geochemical approaches, therefore, provides a robust framework for investigating pedogenic differentiation and supports high-resolution paleoenvironmental reconstruction in regions dominated by weakly magnetic parent materials. Full article

The usage of magnetic nanoparticles (MNPs), particularly iron oxide-based systems such as magnetite (${\mathrm{Fe}}_3$${\mathrm{O}}_4$) and maghemite ($\gamma$-${\mathrm{Fe}}_2$${\mathrm{O}}_3$), has significantly advanced the field of theranostics. These nanoparticles unite therapeutic and diagnostic capabilities due to their favorable magnetic properties and surface engineering potential. However, the path from synthesis to clinical application poses substantial challenges, including optimization of structure–property–function relationships, biocompatibility issues, and effective surface functionalization. Various synthesis methods, such as co-precipitation and thermal decomposition, aim to achieve specific nanoparticle characteristics, although they encounter obstacles related to scalability and reproducibility. Furthermore, characterizing these systems through structural, microstructural and spectroscopic techniques is vital to determine their functional efficacy and ensure their safe biomedical usage. This review comprehensively examines recent advancements and identifies existing challenges in the clinical translation of MNPs, highlighting the need for refined methods and standardized protocols to effectively exploit their theranostic potential. It outlines future directions, emphasizing the importance of green synthesis and robust characterization frameworks to enhance the integration of MNPs in personalized medicine. Full article

Linear α-olefins (LAOs) from CO/H₂ represent an attractive non-petroleum route, yet their selective formation over Fe catalysts is often limited by CO₂ formation via water–gas shift (WGS) reaction and by secondary hydrogenation that consumes terminal olefins. In this work, we demonstrate that these competing pathways can be regulated on carbon-nanotube (CNT) supported Fe catalysts by controlling the CNT interfacial oxygen environment through NO treatment or high-temperature annealing and by adjusting the Mn incorporation protocol between co-impregnation and stepwise addition. Under identical reaction conditions at 280 °C and 3.0 MPa with an H₂-to-CO ratio of 1, high-temperature treated CNTs improve olefin preservation and LAO retention compared with NO-treated CNTs. Mn promotion further shifts selectivity toward α-olefins and lowers CO₂ selectivity. At the same Fe-to-Mn ratio, the Mn introduction sequence produces distinct reducibility and CO-binding behaviors that lead to different steady-state oxide and carbide phases. XPS, H₂-TPR, and CO-TPD collectively suggest that CNT pretreatment and the Mn protocol modulate near-surface oxygen speciation, reduction kinetics, and CO adsorption strength. Mössbauer spectroscopy confirms a predominantly χ-Fe₅C₂ population and indicates the presence of ε-Fe₂C in selected samples together with residual oxide and superparamagnetic Fe species. These results highlight the importance of controlling the CNT–metal interface and Mn–Fe proximity to enhance LAO retention under high-temperature CO hydrogenation. Full article

Regrettably, glioblastoma multiforme (GBM) remains the deadliest form of brain cancer, with a very unfavorable prognosis for life expectancy for the patient. We report, for the first time, the green colloidal synthesis of cobalt-doped magnetic iron oxide nanoparticles (Co-MNPs) as aqueous ferrofluids, using two anionic polysaccharide biopolymers, hyaluronic acid (HA) and carboxymethyl cellulose (CMC), as surfactants. These ferrofluids based on magnetite nanoparticles (HA@Co-MNP and CMC@Co-MNP) demonstrated superparamagnetic properties and magnetic-to-thermal conversion upon exposure to an alternating magnetic field (AMF), with the extent of conversion dependent on surfactant type. In addition, the ferrophase acted as a nanozyme, mimicking peroxidase-like activity in response to hydrogen peroxide, which is present at higher levels in tumor cells. The coupling of magnetic-heat capabilities with biocatalytic behavior enhances glioblastoma cell elimination and suppresses 3D neurospheroid growth. The results also showed that active targeting based on the HA biopolymer shell, due to its affinity for CD44 membrane receptors overexpressed in GBM, outperformed CMC-coated ferrofluid analogs. These magnetocatalytic-responsive nanoplatforms offer a broad avenue for the diagnosis and therapy of numerous cancers, potentially improving patients’ quality of life and prognoses. Full article

The aim of this study was to synthesize alginate hydrogel beads using ionotropic gelation containing pH-sensitive magnetic reduced graphene oxide (MGO). MGO was prepared using a hydrothermal method and surrounded by alginate beads. FTIR, XRD, FESEM, TEM, VSM and TGA showed that the synthesized beads have a quasi-spherical structure, exhibit superparamagnetic behavior, and are thermally stable up to 350 °C. The model drug, quercetin, was loaded into these particles with an efficiency of 25.8%. These particles showed a pH-dependent release. HFF-2 and Caco-2 cells were used to investigate cytotoxicity. At a concentration of 140 μg/mL, more than 80% viability was observed in HFF-2 cells and anticancer effects were observed on Caco-2 cells with a decrease in viability of less than 50% at a concentration of 200 μg/mL. The obtained cell culture results indicate that the hydrogel beads are biocompatible and act as a drug delivery system. Full article

Nanoparticles of ferrimagnetic magnetite (Fe₃O₄) are cornerstones of modern nanoscience and technology, primarily due to their superparamagnetic behavior. Beyond traditional applications in magnetorheology and magnetic hyperthermia, these materials are increasingly vital in fields like active matter, where precise surface fine-tuning is crucial. While coating isotropic, quasi-spherical magnetite nanoparticles with silica is a well-established and versatile route towards functionalization, transferring this achievement to nanorod systems remains a significant challenge. Successful coating of these high-aspect-ratio geometries would allow to exploit the direction-dependent properties and increased magnetic anisotropies. However, current literature largely focuses on polycrystalline rods composed of small, clustered subunits, which limits their magnetic potential. This work describes a breakthrough in the homogeneous silica coating and stabilization of monocrystalline magnetite nanorods. We demonstrate that the superior magnetic properties of these “naked” monocrystalline rods induce strong dipole-dipole interactions, which trigger aggregation and typically prevent the isolation of individual and homogeneously coated core-shell nanoparticles. By investigating the specific mechanisms of this aggregation, we established a robust coating procedure that yields the desired isolated particles. Critically, we show that the magnetite nanorods retain their monocrystalline integrity within the silica shell, thereby preserving the enhanced magnetic properties of the original nanocrystals. Full article

We developed an alkaline phosphatase (AP) chemiluminescence immunoassay method by combining the superparamagnetic magnetic beads and the biotin–streptavidin signal amplification system to detect the triazolone and tebuconazole in wheat. Through optimization of the extraction solution and extraction time, acetonitrile–PBS was selected as the extraction solution with an extraction time of 5 min as the optimal pretreatment condition. Optimizing the dilution ratio of antigen antibodies, the optimal detection conditions were selected as the dilution ratios of 1:8000 and 1:20,000 for the triazolone monoclonal antibody solution and biotinylated triazolone solution, and 1:4000 and 1:20,000 for the tebuconazole monoclonal antibody solution and biotinylated tebuconazole solution, respectively. Under the optimal conditions, the method demonstrated that the limits of detection (LOD) of triazolone and tebuconazole were 0.002835 μg·mL⁻¹ and 0.00064 μg·mL⁻¹, respectively. The recovery rate was between 90.1% and 103.6%, and the relative standard deviation (RSD) was lower than 10%. The cross-reaction rates for structural analogs were all less than 0.1%, showing good specificity. In actual sample detection, this method did not detect triazolone and tebuconazole, and the results were consistent with UHPLC-MS/MS. Full article

The tumor microenvironment, characterized by higher acidity, hypoxia, and dense cellular structures, plays a pivotal role in cancer progression, therapeutic resistance, and treatment response. Nanoparticle-based contrast agents enable the precise delineation of solid regions within heterogeneous tumors through advanced molecular imaging techniques. Since 1956, ultrasound (US) medical imaging has provided essential anatomical and functional insights about internal organs. More recently, magnetomotive ultrasound (MMUS) has emerged as a promising imaging modality, using a modulated magnetic field to exert force on superparamagnetic iron oxide nanoparticles (SPIONs), inducing motion in the surrounding tissues through mechanical coupling. In parallel, magnetic hyperthermia (MH), which employs localized heating by alternating magnetic fields, has demonstrated significant potential in selectively destroying cancer cells while sparing healthy tissues. This review summarizes the current state of IONP-based contrast agents, with particular emphasis on their use in MH for cancer treatment, as well as their potential in multimodal imaging, including MMUS, and photoacoustic (PA) imaging. The advantages and limitations of IONPs in tumor detection and characterization are discussed, examining the development of surface-functionalized MNPs, and analyzing how material properties and environmental factors affect their diagnostic and therapeutical performance. Finally, strategies for combining MMUS and PA modalities for pre-clinical cancer imaging are proposed. Full article

Magnetic and electromagnetic techniques have been applied successfully to mineral exploration discovery. Both techniques rely on inferring the distribution of subsurface physical properties based on ground, airborne or borehole field measurements. Consequently, interpretation methods relating field measurements to underground physical properties are key to geophysical method success. Over the last 15 years, with the evolution of computer processing techniques, interpretation methods have matured and have seen numerous developments, from approximate interpretation to 3D inversion. The recent study of the scientific literature on magnetic and electromagnetic interpretation followed by an analysis of the distribution of the publication of these studies publication (and the citation numbers quoted) outline the research on these topics. The majority of studies are on electromagnetism, with an emphasis on numerical modeling, approximations, superparamagnetism, and induced polarization. In magnetics, the most popular studies were on remanence magnetization inversion and Euler deconvolution. Studies applicable to both methods involved 3D inversion, artificial intelligence, and open-source software. The number of citations reveals a different picture than the number of publications, where the same categories are present but magnetic study citations dominate, indicating in general a time lag of 10 years. The results of this review may help direct future research in these areas. Full article

The effective treatment of aggressive brain tumors, such as glioblastoma, is critically hindered by the blood-brain barrier (BBB) and the non-specific clearance of therapeutic agents by the immune system. Superparamagnetic iron oxide nanoparticles (SPMNPs) offer a powerful theranostic platform, combining magnetic resonance imaging (MRI)-based diagnostics with therapeutic delivery and hyperthermia. However, their clinical translation requires sophisticated strategies to ensure precise delivery to the tumor site. This review examines innovative functionalization strategies to enhance the targeting and efficacy of SPMNPs. Specifically, it addresses the various strategies for coating magnetic nanoparticles with carbohydrates, including both covalent and non-covalent methods, and the subsequent functionalization of these glycoconjugates to exploit the unique biological environment of brain tumors. The use of glycoconjugates on the nanoparticle surface is a key strategy, leveraging the altered glycosylation patterns and overexpression of specific lectins on glioma cell surfaces to achieve highly selective cellular targeting. The review details the synergistic effect achieved by combining these functionalized nanoparticles with external magnetic field guidance. This combination provides a dual-action mechanism: the magnetic field actively guides the nanoparticles across the BBB and concentrates them within the tumor mass, while the carbohydrate coating ensures specific cellular uptake, thereby significantly improving local therapeutic concentration and minimizing systemic toxicity. The scope of this review includes the development and evaluation of carbohydrate-coated SPMNPs, outlining their optimized physicochemical properties for both in vitro and in vivo imaging and treatment of cancerous brain tissues. This comprehensive evaluation represents a critical advancement in biomedicine, aiming to improve the prognosis for patients with brain cancer through more precise and effective therapeutic interventions. Full article

Transition metal (TM)-doped zinc oxide (ZnO) and zirconium dioxide (ZrO₂) nanocrystals exhibit complex correlations between crystal structure, defect chemistry, vibrational properties, and magnetic behavior that are strongly governed by synthesis route and dopant incorporation mechanisms. This review critically summarizes recent progress on Fe-, Mn-, and Co-doped ZnO and ZrO₂ nanocrystals synthesized by wet chemical, hydrothermal, and microwave-assisted hydrothermal methods, with emphasis on synthesis-driven phase evolution and apparent solubility limits. ZnO and ZrO₂ are treated as complementary host lattices: ZnO is a semiconducting, piezoelectric oxide with narrow solubility limits for most 3d dopants, while ZrO₂ is a dielectric, polymorphic oxide in which transition metal doping may stabilize tetragonal or cubic phases. Structural and microstructural studies using X-ray diffraction, electron microscopy, Raman spectroscopy, and Mössbauer spectroscopy demonstrate that at low dopant concentrations, TM ions may be partially incorporated into the host lattice, giving rise to diluted or defect-mediated magnetic behavior. When solubility limits are exceeded, nanoscopic secondary oxide phases emerge, leading to superparamagnetic, ferrimagnetic, or spin-glass-like responses. Magnetic measurements, including DC magnetization and AC susceptibility, reveal a continuous evolution from paramagnetism in lightly doped samples to dynamic magnetic states characteristic of nanoscale magnetic entities. Vibrational spectroscopy highlights phonon confinement, surface optical phonons, and disorder-activated modes that sensitively reflect nanocrystal size, lattice strain, and defect populations, and often correlate with magnetic dynamics. Rather than classifying these materials as diluted magnetic semiconductors, this review adopts a synthesis-driven and correlation-based framework that links dopant incorporation, local structural disorder, vibrational fingerprints, and magnetic response. By emphasizing multi-technique characterization strategies required to distinguish intrinsic from extrinsic magnetic contributions, this review provides practical guidelines for interpreting magnetism in TM-doped oxide nanocrystals and outlines implications for applications in photocatalysis, sensing, biomedicine, and electromagnetic interference (EMI) shielding. Full article