No, humans will not operate tiny submarines injected into patients. But researchers, led by Joseph Wang, a professor of engineering at the University of California, San Diego, have created self-propelled microrockets that use their surrounding environment as fuel.

In the development of self-propelled microrockets (or micromotors), fuel systems have long presented problems, since both have previously relied on cell-damaging hydrogen peroxide or cumbersome magnetic and electrical guiding systems. This new micromotor, on the other hand, is capable of exclusively using substances in its surrounding environment such as water for fuel, preventing any tissue damage that other fuel systems may have inflicted.