Action of magnetic nanoparticles on cancer cells. (Credit: Celia Sousa)

Small magnetic objects are showing promise in the biomedical field. Magnetic nanostructures have interesting properties that enhance novel applications in medical diagnosis and allow the exploration of new therapeutic techniques.

One especially interesting advance involves an exotic nanodisc configuration, known as a vortex state, where magnetic moments arrange into a curly geometry. Isolating and separating cells from a blood or tissue sample is crucial for a variety of medical applications, such as gene therapy or cancer diagnosis and treatment. Standard procedures involve filtration and centrifugation, but cells of similar sizes or densities cannot be separated this way.

Nanodiscs, either in a vortex state or a synthetic antiferromagnetic configuration, consist of two ferromagnetic layers separated by one nonmagnetic layer. The surface of the small structures can be treated with fluorescent probes, allowing the investigators to observe motion of the particles in response to an applied field.

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