Science fiction has become reality at University of Pittsburgh’s Swanson School of Engineering (SSOE), where researchers are developing microscopic medical robots that are able to move through the bloodstream.
Decades after the exploits of Fantastic Voyage and Innerspace—two movies that sent miniaturized scientists into battle with tumors and blood cells—SSOE associate professor Dr. Sung Kwon Cho and his team are creating micro-swimmer drones that can be placed inside and navigated through the human body.
Designed by Cho, the drones—which are called swimmers—measure around the same diameter as a strand of human hair, and are driven by ultrasound waves. When the waves pass through gaseous bubbles implanted into the swimmer via tiny cylindrical tubes, Cho and his team can propel the swimmer forward or change its direction.

Cho and his team recently received a $724,691 grant from the National Science Foundation (NSF) to continue working on the swimmers over the next three years. They plan to use the funds to see whether or not adding more bubble-filled tubes to the swimmers will make them easier to manipulate.
“We still have many challenging issues we need to go over,” says Cho.
Other researchers have explored ways to direct tiny medical robots though the body— including hitching devices to bacteria—but Cho’s swimmer is considered safer and less expensive to use than previous designs. It could also be easily integrated into most clinics, which are already outfitted with ultrasound machines.
The swimmers offer a wide variety of potential medical applications, including breaking down and removing kidney stones, attacking and removing parasites, cleaning burnt or wounded tissue, and enabling more localized drug delivery.
“You can control it so you deliver the drug to the target area, and not the entire body,” says Cho, adding that the swimmers could prevent unwanted side effects from a drug having to travel through the bloodstream.
So far, Cho and his team have successfully tested their method in water and blood. They also plan to use the NSF grant to test the swimmers in conditions similar to that of living organs.
Watch a video of the micro-swimmer drone below: