Researchers have devised a protein “switch” that instructs cancer cells to produce their own anti-cancer medication.

The researchers, led by Marc Ostermeier, a Johns Hopkins chemical and biomolecular engineering professor in the Whiting School of Engineering, showed that these switches, working from inside the cells, can activate a powerful cell-killing drug when the device detects a marker linked to cancer. The goal, the scientists said, is to deploy a new type of weapon that causes cancer cells to self-destruct while sparing healthy tissue.