Ever since the 1966 sci-fi movie “Fantastic Voyage,” scientists have envisioned steering tiny rockets through the human bloodstream to deliver drugs to tumors and unclog arteries. During the past decade, some researchers have designed microscale motors, but those objects typically run on toxic fuel or can’t function in high-salt environments, properties that have barred their entry into living systems. Now, researchers led by Thomas E. Mallouk and Tony Jun Huang of Pennsylvania State University have for the first time propelled gold nanorod motors around the innards of living cells (Angew. Chem. Int. Ed. 2014, DOI: 10.1002/anie.201309629). HeLa cervical cancer cells took up the 3-µm-long, 300-nm-wide rods during a 48-hour incubation period. When the team placed the cells in an ultrasound chamber, acoustic waves scattered off the metallic rods, nudging the micromotors along at a speed of 60 µm per second. “It was interesting to see their erratic motion inside the cells,” Mallouk says. The rods zipped forward for short distances before crashing into organelles and changing direction. According to Mallouk, the team would like to better understand this propulsion mechanism as well as the mechanical and chemical effects the motors have when bumping along.