A brand-new engineering approach at Carnegie Mellon University is creating “designer” biological robots using human lung cells.
Known as AggreBots, these microscale living machines may one day traverse the body to deliver therapeutic or mechanical interventions once their motility patterns are fully controlled.
Biobots are microscopic, man-made biological machines capable of autonomous movement and programmed behaviors.
Traditionally, researchers have relied on muscle fibers to power these tiny robots, enabling them to contract and relax like real muscles.
A promising alternative lies in cilia, the nanoscopic, hair-like propellers that move fluids in the body or help some aquatic creatures, like Paramecium or comb jellies, swim.
Controlling the exact shape and structure of cilia-powered biobots, or CiliaBots, has remained a significant challenge.
The Ren lab at Carnegie Mellon has developed a novel modular assembly strategy for CiliaBots. By spatially aggregating tissue spheroids engineered from lung stem cells, they can create AggreBots with customizable motility.
The approach allows the inclusion of spheroids bearing genetic mutations that render specific cilia regions immotile.
Controlled cilia for precision
Dhruv Bhattaram, first author and biomedical engineering Ph.D. student, compared the method to removing oars from selected locations on a rowboat while paddling. “We’re pushing forward an alternative method of powering biobot tissues with our AggreBots,” he explained.
“Through the process of fusing together different spheroids into different shapes, together with the inclusion of nonfunctional spheroids, we can precisely control the location and abundance of cilia propellers on the tissue’s surface to direct CiliaBot behavior for the first time. This is a seminal step forward that we and others can invest time into for productive outcomes.”
Victoria Webster-Wood, associate professor of mechanical engineering, added, “The AggreBots approach adds a new design dimension to these types of biobots and biohybrid robots. Being able to combine different ciliated and non-ciliated elements modularly will allow future researchers to create biobots with specific engineered mobility patterns. Because the AggreBots are made entirely from biological materials, they are naturally biodegradable and biocompatible, which may enable their direct application in medical settings in the future.”
Medical and research promise
The platform could benefit a broad range of users, including the biorobotics community, clinicians, and medical researchers studying cilia-related diseases such as primary ciliary dyskinesia or the thick mucus in cystic fibrosis.
Notably, CiliaBots can be made from a patient’s own cells, offering the potential for personalized therapeutic delivery vehicles without immune rejection.
Xi (Charlie) Ren, associate professor of biomedical engineering, emphasized, “Motility matters, because the body is a complex environment. Cellular delivery of therapeutics has great potential, but without a proper propulsion mechanism, cells can easily get stuck.
We’ve laid down a path that people can use to control CiliaBot motility. From helping us understand the health impact of environmental hazards to facilitating in vivo therapeutic delivery, CiliaBots have a swath of potential uses, and it’s exciting to be part of their evolution.”
AggreBots represent a major step in biohybrid robotics, combining modular design, biodegradable materials, and precise control over motility to open up possibilities for research, personalized medicine, and future therapeutic applications.
The study has been published in the journal Science Advances.