Search Results (28)

Magnetic graphene composites have emerged as a frontier material platform, offering designable properties and multifunctional integration across environmental, biomedical, electromagnetic, and energy applications. Despite extensive research, a coherent knowledge framework that systematically connects synthesis, structure, property, and application remains lacking. This review addresses this gap by establishing an integrated “synthesis–structure–property–application” design paradigm. We first propose a four-tier evolutionary framework for synthesis strategies, tracing the progression from modular in-situ assembly, substrate-guided single-component in-situ formation, and synchronous in-situ formation to molecular-scale precursor co-conversion. This framework reveals the causative relationships between synthesis pathways and microstructures, and culminates in an application-oriented synthesis decision-making tool that enables rational strategy selection. Building on this synthesis foundation, we systematically analyze three core structural regulation strategies—interface engineering, defect and doping engineering, and hierarchical structure construction—demonstrating how they function as synergistic “control knobs” for tailoring composite properties. Through detailed case studies across four application domains, we quantitatively show how targeted structural design drives performance breakthroughs: enabling high-capacity and selective pollutant removal in environmental remediation; constructing intelligent theranostic platforms in biomedicine; reconciling the “thin, lightweight, broadband, and strong” paradox in electromagnetic interference (EMI) shielding; and ensuring long-cycle stability of high-capacity electrodes in energy storage. Finally, we summarize the paradigm shift from “functional combination” to “performance synergy” and outline future directions, including dynamic intelligent systems, sustainable manufacturing, and data-driven design. This review provides a systematic theoretical framework and practical roadmap for the rational design and on-demand fabrication of MGCs, marking the field’s transition from empirical exploration toward predictive, design-driven science. Full article

Magnetic materials have demonstrated considerable potential for applications in the field of energy storage. Spinel-type CoFe₂O₄ possesses both good redox activity and structural stability, but its magnetism may affect the electrochemical performance. During the high-temperature carbonization and activation processes, the magnetism is significantly weakened, thereby exerting only a limited effect on device performance. To address the issues of high cost and poor environmental friendliness of traditional electrode materials, two types of waste biomass, namely banana peels and sunflower seed shells, were employed as carbon sources for the preparation of Y-doped CoFe₂O₄/carbon composites in this study. Y-doped CoFe₂O₄/banana peel carbon was used as the positive electrode, while Y-doped CoFe₂O₄/sunflower seed shell carbon was used as the negative electrode. The results indicate that the CoFe₂O₄/BPC cathode doped with 0.4% Y has the best performance, with a specific capacitance of 1788 F/g at 1 A/g and a retention rate of 98% after 10,000 cycles. In addition, the SSPC anode exhibited a specific capacitance of 350 F/g and excellent cycling stability. The assembled device achieved a specific capacitance of 190 F/g at 1 A/g and a capacitance retention rate of 83.6% after 10,000 cycles at 5 A/g, demonstrating good energy density, power density and cycling stability. This research provides experimental evidence for the development of low-cost supercapacitors based on biomass. Full article

Magnetically actuated catheters have attracted increasing attention for minimally invasive interventions because they enable remote, non-contact steering in confined and tortuous anatomical environments. However, integrating magnetic actuation, electroablation capability, and high structural compliance into a single soft catheter remains challenging. Here, we present a coaxially printed magnetically actuated electroablation catheter (MEC). The MEC is fabricated via a coaxial 3D printing process, combining a highly flexible PDMS outer sheath with a continuously deformable eutectic gallium–indium (eGaIn) conductive core, followed by the distal assembly of a magnetic ring and a copper electrode. This structural design preserves intrinsic mechanical flexibility while maintaining stable electrical conductivity under bending deformation. To achieve active catheter steering, an eight-axis electromagnetic actuation system was developed to generate controllable magnetic fields for tip deflection and guidance. The MEC exhibited effective navigation and manipulation in maze traversal and selective navigation within a 3D-printed vascular model. Furthermore, ex vivo porcine liver and in vivo rat liver electroablation experiments verified that the MEC could be magnetically navigated to designated sites for localized electroablation. This work provides a new strategy for precise, minimally invasive ablation of target tissues in confined and difficult-to-access anatomical environments. Full article

Magnetic-field-assisted electrocatalysis offers a powerful route to enhance the oxygen evolution reaction (OER) by coupling spin-dependent effects with magnetohydrodynamic phenomena. Here, we present a unified study of cobalt ferrite (CoFe₂O₄)-based nanofilms, elucidating the combined roles of rare-earth doping, nanoparticle size, film morphology, and electrode substrate magnetism on OER performance under external magnetic fields. The effect of UV-light irradiation is also investigated. CoFe₂O₄ and yttrium-doped CoFe₂O₄ nanoparticles were synthesized via thermal decomposition and self-combustion routes, yielding single-domain particles with distinct structural and magnetic properties, and assembled into homogeneous nanofilms using the Langmuir–Blodgett technique. Electrocatalytic measurements in alkaline media reveal that intrinsic OER activity is primarily governed by film compactness and charge-transfer efficiency, while the magnitude of magnetic-field-induced enhancement depends on the magnetic response of both the nanofilms and the supporting electrode. Ferromagnetic substrates promote enhanced catalytic activity under magnetic fields, whereas diamagnetic substrates can exhibit suppressed performance. Across all systems, the strongest enhancement is observed when the magnetic field is applied parallel to the electrode surface, reflecting the combined effects of spin polarization and Lorentz-force-driven mass transport. UV-light irradiation is also evaluated as an external stimulus to promote the reaction. Our findings establish a comprehensive framework for designing magnetically assisted OER electrocatalysts and demonstrate that magnetic-field effects can rival or complement rare-earth doping or UV-light irradiation, offering a sustainable pathway toward high-efficiency water oxidation. Full article

Colorectal cancer (CRC) remains a significant global health burden, mainly due to late diagnosis and chemotherapy resistance. Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine associated with tumor progression, has emerged as a promising biomarker in CRC. However, its clinical utility is limited by the lack of rapid and accessible detection methods. In this study, we report an electrochemical immunotechnology for the sensitive and selective quantification of MIF protein in CRC tissue samples. By combining magnetic microparticles (MMPs), antibody-based recognition, horseradish peroxidase (HRP) labeling, and amperometric transduction at disposable screen-printed carbon electrodes (SPCEs), the developed methodology displayed a linear dynamic range from 0.24 to 20 ng mL⁻¹, enabling quantification across clinically relevant MIF levels, and achieving a low limit of detection (0.07 ng mL⁻¹). In addition, the developed method is the only one reported for MIF assembled on MMPs and addresses its determination in a relevant oncological scenario (paired non-tumoral (NT) and tumoral (T) tissues from individuals diagnosed with CRC at different stages of the disease). The analysis, requiring only 100 ng of tissue extract, allowed efficient discrimination between NT and T paired tissues, and successfully differentiated between healthy, early (I–II) and advanced (III–IV) CRC stages, achieving these results in just 105 min. Full article

The rapid and timely evaluation of the mental health of emergency rescuers can effectively improve the quality of emergency rescues. However, biosensors for mental health evaluation are now facing challenges, such as the rapid and portable detection of multiple mental biomarkers. In this study, a non-invasive, flexible, wearable electrochemical biosensor was constructed based on the self-assembly of nanomagnetic beads for the rapid detection of cortisol in interstitial fluid (ISF) to assess the mental stress of emergency rescuers. Based on a one-step reduction, gold nanoparticles (AuNPs) were functionally modified on a screen-printed electrode to improve the detection of electrochemical properties. Afterwards, nanocomposites of MXene and multi-wall carbon nanotubes were coated onto the AuNPs layer through a physical deposition to enhance the electron transfer rate. The carboxylated nanomagnetic beads immobilized with a cortisol antibody were treated as sensing elements for the specific recognition of the mental stress marker, cortisol. With the rapid attraction of magnets to nanomagnetic beads, the sensing element can be rapidly replaced on the electrode uniformly, which can lead to extreme improvements in detection efficiency. The detected linear response to cortisol was 0–32 ng/mL. With the integrated reverse iontophoresis technique on a flexible printed circuit board, the ISF can be extracted non-invasively for wearable cortisol detection. The stimulating current was set to be under 1 mA for the extraction, which was within the safe and acceptable range for human bodies. Therefore, based on the positive correlation between cortisol concentration and mental stress, the mental stress of emergency rescuers can be evaluated, which will provide feedback on the psychological statuses of rescuers and effectively improve rescuer safety and rescue efficiency. Full article

A magnetically assembled electrode (MAE) is a modular electrode format in electrochemical oxidation wastewater treatment. MAE utilizes magnetic forces to attract the magnetic catalytic auxiliary electrodes (AEs) on the main electrode (ME), which has the advantages of high efficiency and flexible adjustability. However, the issue of the insufficient polarization of the AEs leaves the potential of this electrode underutilized. In this study, natural tourmaline (Tml) particles with pyroelectric and piezoelectric properties were utilized to solve the above issue by harvesting and converting the waste energy (i.e., the joule heating energy and the bubble striking mechanical energy) from the electrolysis environment into additional electrical energy applied on the AEs. Different contents of Tml particles were composited with Fe₃O₄/Sb-SnO₂ particles as novel AEs, and the structure–activity relationship of the novel MAE was investigated by various electrochemical measurements and orthogonal tests of dye wastewater treatment. The results showed that Tml could effectively enhance all electrochemical properties of the electrode. The optimal dye removal rate was obtained by loading the AEs with 0.2 g·cm⁻² when the Tml content was 4.5 wt%. The interaction of current density and Tml content had a significant effect on the COD removal rate, and the mineralization capacity of the electrode was significantly enhanced. The findings of this study have unveiled the potential application of minerals and energy conversion materials in the realm of electrochemical oxidation wastewater treatment. Full article

Lung cancer is the most common type of cancer diagnosed worldwide and is also among the most fatal. Early detection, before symptoms become evident, is fundamental for patients’ survival. Therefore, several lung cancer biomarkers have been proposed to enable a prompt diagnosis, including neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA). NSE and CEA are two serum proteins whose elevated levels have been associated with lung cancer. Hence, in this study, impedimetric biosensors (immunosensors) able to quantify NSE and CEA were developed as proof-of-concept devices for lung cancer diagnosis. The sensing platform exploited for the immunosensors comprises a novel combination of a magnetic platform, screen-printed gold electrode (SPGE), and magnetic nanobeads (MB). The MB were functionalized with antibodies to capture the analyte from the sample and to move it over the sensing area. The immunosensors were then developed by immobilizing another set of antibodies for either CEA or NSE on the SPGE through formation of self-assembled monolayer (SAM). The second set of antibodies enabled a sandwich assay to be formed on the surface of the sensor, while MB manipulation was applied during the sensor performance to depict a microfluidic system and increase antigen–antibody complex formation prior to CEA or NSE detection and quantification. The optimized immunosensors were successfully tested to measure various concentrations of CEA and NSE (0–100 ng/mL) in both phosphate buffer and 100% human serum samples. Clinically relevant detection limits of 0.26 ng/mL and 0.18 ng/mL in buffer and 0.76 ng/mL and 0.52 ng/mL in 100% serum for CEA and NSE, respectively, were achieved via electrochemical impedance spectroscopy with the use of potassium ferri/ferrocyanide as a redox probe. Hence, the two immunosensors demonstrated great potential as tools to be implemented for the early detection of lung cancer. Full article

Crimping processes are commonly used in industry to join two tubular parts together. In the case of positive clearance crimping, one of the two parts must be plastically deformed to fill the initial clearance and block elastic deformations in the second one. The strength of the assembly will then depends on the residual contact pressure established at the interface. Quasi-static processes are the most commonly used to perform these operations, but over the past two decades, there has been a growing interest in the use of dynamic crimping by magnetic pulse. Processes that generate high-strain rate allow to reduce the springback, which is of great interest for crimping. However, its use is limited if the part to be deformed is made of a poor electrical conductor material or if its dimensions are too small. This paper presents an alternative for dynamically crimping tubes within rings using electrohydraulic process. An experimental equipment has been designed to guide and amplify pressure waves to the area to be deformed. Two amplifiers called acoustic and mechanical pulse shapers (APS and MPS) have been tested and allow to reach hoop strain rate at about 1000 and 100 s${}^{-1}$ respectively. An analytical model was also built allowing to define the stored energy and the inter-electrodes distance to maximize the pressure. Results of push-out tests are also presented and demonstrate the ability of the electrohydraulic crimping process coupled with the MPS to crimp small 316L tubes into rings made of the same material, but achieving crimping successfully with the APS still require further work. Full article

A rapid and convenient homogeneous aptamer sensor with high sensitivity is highly desirable for the electrochemical detection of tumor biomarkers. In this work, a homogeneous electrochemical aptamer sensor is demonstrated based on a two-dimensional (2D) nanocomposite probe and nanochannel modified electrode, which can realize sensitive detection of carcinoembryonic antigen (CEA). Using π-π stacking and electrostatic interaction, CEA aptamer (Apt) and cationic redox probe (hexaammineruthenium(III), Ru(NH₃)₆³⁺) are co-loaded on graphite oxide (GO), leading to a 2D nanocomposite probe (Ru(NH₃)₆³⁺/Apt@GO). Vertically ordered mesoporous silica-nanochannel film (VMSF) is easily grown on the supporting indium tin oxide (ITO) electrode (VMSF/ITO) using the electrochemical assisted self-assembly (EASA) method within 10 s. The ultrasmall nanochannels of VMSF exhibits electrostatic enrichment towards Ru(NH₃)₆³⁺ and size exclusion towards 2D material. When CEA is added in the Ru(NH₃)₆³⁺/Apt@GO solution, DNA aptamer recognizes and binds to CEA and Ru(NH₃)₆³⁺ releases to the solution, which can be enriched and detected by VMSF/ITO electrodes. Based on this mechanism, CEA can be an electrochemical detection ranging from 60 fg/mL to 100 ng/mL with a limit of detection (LOD) of 14 fg/mL. Detection of CEA in human serum is also realized. The constructed homogeneous detection system does not require the fixation of a recognitive aptamer on the electrode surface or magnetic separation before detection, demonstrating potential applications in rapid, convenient and sensitive electrochemical sensing of tumor biomarkers. Full article

Magnetic activated carbon particles (Fe₃O₄/active carbon composites) as auxiliary electrodes (AEs) were fixed on the surface of Ti/Sb-SnO₂ foil by a NdFeB magnet to form a new magnetically assembled electrode (MAE). Characterizations including cyclic voltammetry, Tafel analysis, and electrochemical impedance spectroscopy were carried out. The electrochemical oxidation performances of the new MAE towards different simulated wastewaters (azo dye acid red G, phenol, and lignosulfonate) were also studied. Series of the electrochemical properties of MAE were found to be varied with the loading amounts of AEs. The electrochemical area as well as the number of active sites increased significantly with the AEs loading, and the charge transfer was also facilitated by these AEs. Target pollutants’ removal of all simulated wastewaters were found to be enhanced when loading appropriate amounts of AEs. The accumulation of intermediate products was also determined by the AEs loading amount. This new MAE may provide a landscape of a more cost-effective and flexible electrochemical oxidation wastewater treatment (EOWT). Full article

Electrochemical biosensors generally require the immobilization of recognition elements or capture probes on the electrode surface. This may limit their practical applications due to the complex operation procedure and low repeatability and stability. Magnetically assisted biosensors show remarkable advantages in separation and pre-concentration of targets from complex biological samples. More importantly, magnetically assisted sensing systems show high throughput since the magnetic materials can be produced and preserved on a large scale. In this work, we summarized the design of electrochemical biosensors involving magnetic materials as the platforms for recognition reaction and target conversion. The recognition reactions usually include antigen–antibody, DNA hybridization, and aptamer–target interactions. By conjugating an electroactive probe to biomolecules attached to magnetic materials, the complexes can be accumulated near to an electrode surface with the aid of external magnet field, producing an easily measurable redox current. The redox current can be further enhanced by enzymes, nanomaterials, DNA assemblies, and thermal-cycle or isothermal amplification. In magnetically assisted assays, the magnetic substrates are removed by a magnet after the target conversion, and the signal can be monitored through stimuli–response release of signal reporters, enzymatic production of electroactive species, or target-induced generation of messenger DNA. Full article

In this article, a Riga plate is exhibited with an electric magnetization actuator consisting of permanent magnets and electrodes assembled alternatively. This Riga plate creates an electric and magnetic field, where a transverse Lorentz force is generated that contributes to the flow along the plate. A new study field has been created by Sutterby nanofluid flows down the Riga plate, which is crucial to the creation of several industrial advancements, including thermal nuclear reactors, flow metres, and nuclear reactor design. This article addresses the second law analysis of MHD Sutter by nanofluid over a stretching sheet with the Riga plate. The Cattaneo–Christov Double Diffusion heat and mass flux have been created to examine the behaviour of relaxation time. The bioconvection of motile microorganisms and chemical reactions are taken into consideration. Similarity transformations are used to make the governing equations non-dimensional ordinary differential equations (ODE’s) that are subsequently solved through an efficient and powerful analytic technique, the homotopy analysis method (HAM). The effect of pertained variables on velocity, temperature, concentration, and motile microorganism distributions are elaborated through the plot in detail. Further, the velocity distribution enhances and reduces for greater value Deborah number and Reynold number for the two cases of pseudoplastic and dilatant flow. Microorganism distribution decreases with the augmented magnitude of Peclet number $(Pe)$, Bioconvection Lewis number $(Lb)$, and microorganism concentration difference number $(\varpi )$. The entropy production distribution is increased for the greater estimations of the Reynolds number $({\mathrm{Re}}_L)$ and Brinkman parameter $(Br)$. Two sets of graphical outputs are presented for the Sutterby fluid parameter. Finally, for the justification of these outcomes, tables of comparison are made with various variables. Full article

In this article, a Riga plate is exhibited with an electric magnetization actuator consisting of permanent magnets and electrodes assembled alternatively. This exhibition produces electromagnetic hydrodynamic phenomena over a fluid flow. A new study model is formed with the Sutterby nanofluid flow through the Riga plate, which is crucial to the structure of several industrial and entering advancements, including thermal nuclear reactors, flow metres and nuclear reactor design. This article addresses the entropy analysis of Sutterby nanofluid flow over the Riga plate. The Cattaneo–Christov heat and mass flux were used to examine the behaviour of heat and mass relaxation time. The bioconvective motile microorganisms and nanoparticles are taken into consideration. The system of equations for the current flow problems is converted from a highly non-linear partial system to an ordinary system through an appropriate transformation. The effect of the obtained variables on velocity, temperature, concentration and motile microorganism distributions are elaborated through the plots in detail. Further, the velocity distribution is enhanced for a greater Deborah number value and it is reduced for a higher Reynolds number for the two cases of pseudoplastic and dilatant flows. Microorganism distribution decreases with the increased magnitude of Peclet number, Bioconvection Lewis number and microorganism concentration difference number. Two types of graphical outputs are presented for the Sutterby fluid parameter (β = −2.5, β = 2.5). Finally, the validation of the present model is achieved with the previously available literature. Full article

This work consists in the process of preparing magnetic active composite materials based on cotton fibers, iron carbonyl microparticles and barium titanate nanoparticles, and the electrical devices manufactured with them. For different compositions of the aforementioned ingredients, three such composites are manufactured and compacted at constant pressure between two electrodes. In the absence and in the presence of a magnetic field, using an RLC bridge, magnetocapacitive, magnetoresistive and magnetopiezoelectric effects are highlighted in the custom fabricated devices. It is shown that these effects are significantly influenced by the composition of the materials. Based on the model elaborated in this paper, the mechanisms that contribute to the observed effects are described and the theoretical predictions are shown to agree with the experimental data. The obtained results can be used in the assembly of hybrid magnetic active composites, which are low cost, ecological and have other useful physical characteristics for applications. Full article