A form of magnetic levitation can separate living and dead cells without altering or damaging them in any way. The process could be used for everything from drug discovery to tissue engineering.

Cells normally sink to the bottom of the fluid they are grown in. Gozde Durmus at Stanford University in California and her colleagues have developed a way of “levitating” them using magnetism.

“Everything on Earth is magnetic,” says Durmus. Her team puts cells in a fluid containing ions of …