Magnetic fibers weave together medicine, clean water and smart textiles

Imagine a shirt that monitors your heartbeat, a bandage that guides drugs to a tumor with nothing more than a magnet, or a fabric that pulls heavy metals out of contaminated water. None of these ideas requires exotic new physics. They all depend on a class of materials that has quietly been advancing for decades: magnetic fibers, threads that combine the magnetic responsiveness of iron oxide particles and related compounds with the lightness, flexibility and wearability of ordinary textile fibers. A comprehensive new review published in the Journal of Materials Science by Siying Liu, Boyan Li and Yantao Gao of Shanghai University of Engineering Science brings together the state of the art in how these fibers are made, how their properties are tuned, and where they are headed.

The appeal of magnetic fibers lies in a deceptively simple marriage of properties. A fiber is, by geometry, one of the most versatile building blocks humans have ever engineered: it can be woven, knitted, braided or embedded into composites, and it conforms to curved surfaces from aircraft wings to human skin. Add magnetic functionality and the fiber gains an invisible handle. External magnetic fields can move it, deform it, heat it, or use it as a sensor, all without physical contact or wired connections. The review frames this combination as the reason magnetic fibers have become a research hotspot spanning textiles, biomedicine, environmental governance and intelligent materials.

How, then, does one actually make a fiber magnetic? The review organizes the field into several main fabrication routes, each with distinct trade-offs. The most direct approach is to prepare metal fibers themselves, drawing or otherwise forming pure iron, cobalt or nickel into filaments. These deliver the strongest magnetic response but sacrifice the flexibility and processability of polymer textiles. At the opposite end of the spectrum, physical and chemical finishing methods take ordinary fibers, cotton, polyester, cellulose, carbon fiber, and decorate them with magnetic particles after the fact, through dip-coating, electrodeposition or electroless plating. Researchers have used these routes to coat carbon fibers with Fe-Co alloys for electromagnetic wave absorption and to create superparamagnetic cellulose fibers and papers through scalable, simple processes.

Between these extremes sit the spinning methods, which the review treats in detail. Melt spinning, in which a magnetic polymer composite or alloy is extruded through a spinneret and rapidly cooled, offers industrial scalability and good control over fiber diameter, though the rapid quenching conditions strongly influence the resulting microstructure and magnetic properties. Electrospinning, by contrast, uses a high-voltage electric field to draw a charged polymer solution into nanofibers, and it has become the workhorse for producing magnetic nanofibers with diameters far below those achievable by conventional spinning. Studies cited in the review describe in situ electrospinning of Fe3O4/polyvinylpyrrolidone nanofibers, magnetic-field-assisted electrospinning that aligns FeCo particles along the fiber axis, and electrospun Fe3O4/calcium phosphate scaffolds for bone-related applications. A further variant, organometallic complex decomposition, uses metal-organic precursors that decompose into magnetic phases during processing, offering another path to well-dispersed magnetic phases.

Each route carries well-defined limitations, and the review is candid about them. Direct metal fibers are stiff and hard to integrate into soft goods. Coating methods can suffer from poor adhesion and particle shedding, which is why surface modification of textile fibers to improve adhesion is itself an active research area. Electrospinning produces exquisite nanofibers but at low throughput, and the magnetic particles within the spinning solution tend to agglomerate, producing uneven dispersion that undermines both magnetic uniformity and mechanical strength. Melt spinning demands that magnetic fillers survive high processing temperatures. The choice of method, in other words, is always a negotiation between magnetic performance, mechanical integrity, biocompatibility and manufacturability.

Tuning properties goes beyond choosing a fabrication route. The review surveys regulation strategies across four axes: magnetic properties, mechanical properties, thermal stability and biocompatibility. Magnetic performance depends on particle type, size and loading, and on whether the particles are hard magnetic, like neodymium-iron-boron flakes used to make smart textile fabrics, or soft magnetic, like the Fe/Fe3O4 fibers studied for soft magnetic composites, where fiber diameter measurably affects both AC and DC magnetic characteristics. Mechanical properties hinge on how well the magnetic phase bonds to the polymer or carbon matrix and on particle dispersion. Thermal stability matters for applications near heat sources, and biocompatibility is paramount for anything intended to touch or live inside the human body, driving interest in coatings and surface functionalization that render magnetic particles safe and stable in biological environments.

The biomedical applications are arguably the most striking. Magnetic fibers can serve as remotely controlled drug delivery platforms: polymer-magnetic composite fibers have been demonstrated for remote-controlled drug release, where an external field triggers or modulates the release of therapeutic payloads. In tumor diagnosis and therapy, magnetic nanomaterials more broadly support imaging and magnetic hyperthermia, and fiber formats could bring those functions into implantable or wearable geometries. Tissue engineering is another frontier. Magnetic nanofiber scaffolds with suitable mechanical and biological properties have been proposed for bone regeneration, magnetic nanofibrous scaffolds have been shown to accelerate muscle tissue regeneration when combined with external magnetic fields, and magnetotherapy is being explored for tendon regeneration. The underlying idea is that magnetic stimulation can influence cell behavior, from growth to death, giving clinicians a non-invasive lever on biological processes.

Environmental remediation offers a second major application space. Magnetic materials are widely used to adsorb and then magnetically separate contaminants from water, and fiber formats extend this capability. Surface-functionalized magnetic composites have been reviewed extensively for heavy metal ion adsorption, and magnetic fibers and fabrics add the advantage of high surface area and easy handling. Related work on dip-coated fabrics modified with gamma-Fe2O3, epoxy resin and lauric acid demonstrates multifunctional textiles that can separate oil from water while also providing superhydrophobicity and flame retardancy. For a world grappling with industrial wastewater and persistent pollutants such as perfluoroalkyl substances, magnetic fiber-based sorbents that can be collected with a magnet rather than filtered out of slurry represent a genuinely practical advantage.

The third pillar is intelligent materials and textiles. Embedded magnetic fibers allow fiber-reinforced polymer composites to self-monitor strain and bending in real time, because deformation changes the magnetic signature read out by nearby sensors. Magnetostrictive effects, in which a material changes shape in a magnetic field, underpin fiber-optic vector magnetic field sensors and soft actuators. Perhaps most visible to consumers, magnetoelastic soft fibers have been developed for wearable electronics, enabling continuous sensing of pressure, stretch and touch. In parallel, magnetic fabrics are being combined with triboelectric and piezoelectric nanogenerators to create self-powered textiles that harvest biomechanical energy, and magnetotherapeutic textiles aim to bring magnetic field exposure into garments, an area where the review notes both growing interest and the need for careful scientific grounding.

What stands between the laboratory and the wardrobe, the clinic and the water treatment plant? The review identifies three persistent bottlenecks: uneven dispersion of magnetic particles within fiber matrices, difficulty achieving synergistic regulation of magnetic, mechanical and biological properties simultaneously, and immature large-scale preparation technology. Its proposed roadmap follows directly: develop novel surface modification technologies to anchor and disperse particles more uniformly, optimize composite structures so that multiple functions can be engineered together rather than traded off, push the development of large-scale preparation equipment, and expand multifunctional integrated applications that combine sensing, actuation, energy harvesting and therapy in a single fiber platform. If those engineering challenges fall, magnetic fibers could move from a materials science curiosity to an invisible layer of functionality woven through medicine, environmental technology and everyday clothing, a reminder that sometimes the most transformative technologies are the ones you cannot see, only feel the pull of.

Subject of Research: Fabrication methods and applications of magnetic fibers in biomedicine, environmental remediation, intelligent materials and textiles

Article Title: Review: fabrication and applications of magnetic fibers

Article References: Liu, S., Li, B., & Gao, Y. (2026). Review: fabrication and applications of magnetic fibers. Journal of Materials Science, 61(43), 33371-33397. https://doi.org/10.1007/s10853-026-13270-1

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13270-1

Keywords: magnetic fibers, electrospinning, melt spinning, smart textiles, drug delivery, tissue engineering, water purification, magnetotherapy, triboelectric nanogenerators, magnetoelasticity, iron oxide nanoparticles, surface modification