Engineers create designer biobots from human lung cells

Engineers create designer biobots from human lung cells

A completely new technical approach to developing biological “designer” robots using human lung cells is currently being developed in the Ren laboratory at Carnegie Mellon University. These microscale living robots, called AggreBots, may one day be able to traverse the body's complex environments to carry out desired therapeutic or mechanical interventions once better control over their movement patterns is achieved. In a new study published inScientific advancesThe group provides a novel tissue engineering platform that can be used to achieve customizable motility in AggreBots by actively controlling their structural parameters.

Biobots are microscopic, human-made biological machines that move autonomously and are programmable to perform specific tasks or behaviors. Until now, promoting the mobility of biobots has focused on using muscle fibers that allow them to move like real muscles through contraction and relaxation.

A novel, alternative actuation mechanism may be found through the use of cilia, the nanoscopic, hair-like, organic propellers that continuously move fluids in the body (e.g. in the lungs) and aid some aquatic life, e.gParameciumor comb jellies, swim. However, finding a reliable way to control the precise shape and structure of a cilia-powered biobot (CiliaBot for short) and therefore its motility outputs has proven difficult.

The Ren lab pioneered a novel modular assembly strategy for CiliaBots using spatially controlled aggregation of tissue spheroids that the lab produces from lung stem cells. Using this strategy, these aggregated CiliaBots (AggreBots) can incorporate stem cell spheroids that carry a genetic mutation that renders cilia dysfunctional and immobile in certain regions.

Dhruv Bhattaram, lead author of the paper and biomedical engineering Ph.D. The student compared the process to removing the oars from selected points on a rowboat while paddling.

With our AggreBots, we are advancing an alternative method of supplying energy to biobot tissues. Through the process of fusing different spheroids into different shapes and incorporating non-functional spheroids, we can for the first time precisely control the position and frequency of cilia propellers on the tissue surface to control CiliaBot's behavior. This is a critical advancement that we and others can invest time in to achieve productive results.”

Dhruv Bhattaram, first author of the article

“The Aggrebots approach brings a new design dimension to these types of biobots and biohybrid robots,” added Victoria Webster-Wood, associate professor of mechanical engineering. "The ability to modularly combine different ciliated and non-ciliated elements will allow future researchers to create biobots with specific technical movement patterns. Because the Aggrebots are made entirely of biological materials, they are naturally biodegradable and biocompatible, which could enable their direct application in medical environments in the future."

As the Ren lab continues to build on the platform, they recognize that the technology could benefit a broad audience, including the biorobotics community, clinicians and medical researchers studying how cilia function in diseases such as primary ciliary dyskinesia or in the thick, highly viscous mucus of cystic fibrosis. In particular, CiliaBots can be made from patients' own cells, which could be used to create personalized therapeutic carriers without the risk of immune rejection.

Flexibility is important because the body is a complex environment. Cellular delivery of therapeutics has great potential, but without an appropriate propulsion mechanism, cells can easily become stuck. We have established a pathway that people can use to control CiliaBot motility. CiliaBots help us understand the impact of environmental hazards on health and facilitate in vivo therapeutic delivery. They have a wide range of potential uses and it’s exciting to be part of their development.”

Xi (Charlie) Ren, associate professor of biomedical engineering

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