Tiny robotic drug deliveries could soon be treating diseases inside your body. For the first time, micromotors -- autonomous vehicles the width of a human hair -- have cured bacterial infections in the stomachs of mice, using bubbles to power the transport of antibiotics. From a report: "The movement itself improves the retention of antibiotics on the stomach lining where the bacteria are concentrated," says Joseph Wang at the University of California San Diego, who led the research with Liangfang Zhang. In mice with bacterial stomach infections, the team used the micromotors to administer a dose of antibiotics daily for five days. At the end of the treatment, they found their approach was more effective than regular doses of medicine. The tiny vehicles consist of a spherical magnesium core coated with several different layers that offer protection, treatment, and the ability to stick to stomach walls. After they are swallowed, the magnesium cores react with gastric acid to produce a stream of hydrogen bubbles that propel the motors around. This process briefly reduces acidity in the stomach. The antibiotic layer of the micromotor is sensitive to the surrounding acidity, and when this is lowered, the antibiotics are released.