Tiny magnets made by bacteria could be used to kill tumours, say researchers.
A team at the University of Edinburgh has developed a method of making the nanomagnets stronger, opening the way for their use in cancer treatment.
The bacteria-produced magnets are better than man-made versions because of their uniform size and shape, the Nature Nanotechnology study reported.
It is hoped one day the magnets could be guided to tumour sites and then activated to destroy cancerous cells.
The bacteria take up iron from their surroundings and turn it into a string of magnetic particles.
They use the chains of particles like a needle of a compass to orientate themselves and search for oxygen-rich environments.