Erasable MRIs

Mikhail Shapiro, assistant professor of chemical engineering, and his colleagues have developed “erasable” MRI contrast agents that, on command, can blink off. The contrast agents—air-filled protein structures called gas vesicles—emit magnetic signals that collapse when hit with waves of sound, causing them to disappear and making it easier for researchers to interpret the MRI scans. “It’s the same principle behind blinking bicycle lights,” says Shapiro. “Having the lights turn on and off makes them easier to see, but in our case we  just blink off the contrast agent once.”