Jon Dobson, a biomedical engineer at the University of Florida, says detoxification is “a really interesting application” of nanotechnology. His own group has been using magnetic nanoparticles as remote controls to manipulate cellular activity, such as the differentiation of stem cells. “With chemicals, once the process starts, it can be difficult to switch it off. With magnetic technology, you can switch it on and off at will,” Dobson says.

The potential uses of the Swiss group’s method might extend beyond sepsis to other diseases, including blood cancers, Dobson says. For example, it might be possible to design nanomagnets that pair up with circulating leukemia cells and usher them out of the body, thus reducing the risk of metastasis.

O. Thompson Mefford, a nanotechnology expert at Clemson University, says the approach has appeal. He notes that the human body is a highly oxidative environment, and oxidation of iron weakens the magnetic properties of the material. By coating their magnets in carbon, the Swiss group may have come up with a way to prevent this corrosion.

Still, he says, the viability of the technique remains to be seen: “Having high circulation times, no immune response, and having the magnets not cluster with each other, that’s a real challenge.”