Imagine tiny, living robots swimming through your body to deliver medicine right where it’s needed.
Scientists at Carnegie Mellon University are moving closer to making that vision a reality.
Their new study, published in Science Advances, introduces “AggreBots”—microscopic biological robots built from human lung cells.
Biological robots, or “biobots,” are man-made living machines that can move on their own and perform tasks.
In earlier research, scientists built biobots that relied on muscle fibers, which contract and relax like real muscles, to create motion.
But the Carnegie Mellon team has taken a completely different approach—using cilia.
Cilia are tiny, hair-like structures that act like natural propellers. In our lungs, they sweep away mucus and debris.
In water-dwelling creatures such as Paramecium, cilia beat rhythmically to help them swim.
For scientists, using cilia as a propulsion system seemed promising. The problem, however, was figuring out how to shape and arrange these cilia-powered robots so that they moved in predictable ways.
The Ren Lab, led by biomedical engineer Xi (Charlie) Ren, has now solved that challenge with a new engineering method.
Their strategy involves building the robots out of small spherical clusters of lung stem cells, called tissue spheroids.
By carefully arranging these spheroids into different shapes, the researchers can control where the cilia are located on the robot’s surface. To fine-tune this even more, they can use some spheroids with a genetic mutation that makes the cilia in that region nonfunctional.
Dhruv Bhattaram, the study’s first author and a Ph.D. student, compared this process to rowing a boat. If you remove some oars in certain positions, the boat moves differently. Similarly, by adding or removing functional cilia, the team can direct the movement patterns of their tiny robots.
These AggreBots are not only controllable but also entirely made of biological material. This makes them both biodegradable and biocompatible—key features if they are ever to be used inside the human body. According to the researchers, AggreBots could one day travel through complex bodily environments to deliver drugs or perform medical interventions.
The potential uses go beyond medicine. Because the robots are powered by cilia, they may also help scientists better understand diseases where cilia function is impaired, such as primary ciliary dyskinesia or cystic fibrosis. Even more exciting, these robots could be made from a patient’s own cells, lowering the risk of immune rejection if used in treatments.
“Motility matters because the body is a complex environment,” said Ren. “We’ve created a path for controlling how these tiny robots move. From studying how environmental hazards affect human health to developing new ways to deliver therapies directly in the body, CiliaBots have huge potential.”
The research is still at an early stage, but it marks an important step toward using living, cell-based robots in real-world applications. One day, swarms of microscopic AggreBots might carry lifesaving medicine deep into the human body.
