The University of Colorado Boulder's engineering department has created a new category of tiny, self-propelled robots that can move through liquid at extraordinary rates and may one day be used to transport medications to the human body's most difficult-to-reach locations.

In a report released recently in the journal Small, the researchers reveal details about their miniature healthcare providers.

"Imagine if microrobots could perform certain tasks in the body, such as non-invasive surgeries," said Jin Lee, lead author of the study and a postdoctoral researcher in the Department of Chemical and Biological Engineering. "Instead of cutting into the patient, we can simply introduce the robots to the body through a pill or an injection, and they would perform the procedure themselves."

Although Lee and his colleagues are not quite there, the new discovery represents a significant advance for micro robots.

[Learn more about micro robots at GlobalSpec]

The microrobots in the group are extremely small -- only 20 micrometers wide on average, or many timesCreated similar to 3D printing with biodegradable polymers. Image Credit: Shields Lab finer than a human hair. They can move at speeds of about 3 millimeters per second, or nearly 9,000 times their own length, per minute, making them exceptionally quick. Comparatively, that is a lot faster than a cheetah.

They also have a great deal of promise. In the latest trial, the team used fleets of these devices to deliver dosages of the common steroid drug dexamethasone to the bladders of laboratory mice. The findings point to the potential value of microrobots in the treatment of bladder disorders and other human illnesses.

"Microscale robots have garnered a lot of excitement in scientific circles, but what makes them interesting to us is that we can design them to perform useful tasks in the body," said C. Wyatt Shields, a co-author and assistant professor of chemical and biological engineering.

Straight from science fiction

If that sounds like something from a sci-fi flick, that is because it is. In the movie Fantastic Voyage, a team of explorers travel in a shrunken submarine into the body of a comatose man.

"The movie was released in 1966. Today, we are living in an era of micrometer- and nanometer-scale robots," Lee said.

He thinks that, just like in the film, tiny robots could move through a person's bloodstream, looking for specific problems to remedy.

The research group uses a method that is like 3D printing to make the microrobots out of biocompatible polymers. The machines have three small fins and look somewhat like small rockets. They also come with something extra: each robot has a small bubble of air inside it, as when a glass is turned upside down in water. As the machines are placed in an acoustic field, like the sort used in ultrasounds, the bubbles will start to move wildly, pushing the water away and propelling the robots forward.

Fantastic Voyage (1966). Image Credit: 20th Century Fox

The scientists wanted to test their microrobots, so they chose a common condition in people: bladder disease.

Lee stated that the group has a lot of work remaining before microrobots can move throughout actual humans. They want to be sure the machines can fully dissolve in the body.

"If we can make these particles work in the bladder," Lee said, "then we can achieve a more sustained drug release, and maybe patients wouldn't have to come into the clinic as often."