Smart artificial microswimmers—small robots that resemble microorganisms like bacteria or human sperm—could potentially be used for targeted drug delivery, minimally invasive surgery, and even in fertility treatments.
These types of complicated tasks won’t be accomplished by a single microswimmer. Multiple swimmers will be necessary; however, it’s unclear how such groups will move within the chemically and mechanically complex environment of the body’s fluids.
“We know that whenever a swimmer has a neighbor, it swims differently,” says Ebru Demir, an assistant professor of mechanical engineering and mechanics in Lehigh University’s P.C. Rossin College of Engineering and Applied Science. “Birds fly in a V formation because it’s more efficient and it saves them energy. But for a group of microswimmers, we don’t know what the best formation looks like.”
Demir recently received funding through the National Science Foundation’s Faculty Early Career Development (CAREER) Program for her research combining artificial microswimmers with machine learning to build Smart Artificial Microswimmers (SAMs). By embedding AI into centimeter-scale robotic swimmers and comparing their behavior with predictions from simulations, her project aims to uncover the underlying physics that govern their movement in complex fluid environments.
The prestigious NSF CAREER award is given annually to junior faculty members across the U.S. who exemplify the role of teacher-scholars through outstanding research, excellent education, and the integration of education and research. Each award provides stable support at the level of approximately $500,000 for a five-year period.
To study how the swimmers move in both Newtonian and non-Newtonian fluids, Demir will insert microcontrollers that run reinforcement learning algorithms into 3-D printed autonomous robots that are 10-20 centimeters, or about 4-8 inches, in size. Fluids in the human body, such as blood, have non-Newtonian properties, meaning their viscosity, or resistance to flow, changes depending on the stress applied by the swimming body. She will make and use fluids with similar properties in experiments to verify the results of her simulations.
“These swimmers will each contain an AI brain that will give them decision-making capabilities, so they can determine for themselves how to swim better alone, and how to swim better with three or five or 10 companions. It will also be interesting to see if their behavior changes if they are allowed to cooperate and share information.”
For example, she says, a swimmer may move closer to its companion. As it does, it may determine that it’s moving faster. So it moves ever closer. But suddenly, it slows down. It then decides to retreat back to the previous distance where it maintained optimal speed.
“As the SAMs swim, they are constantly interacting with the environment, running that algorithm, and recalculating where they are in that formation and how fast or how efficiently they are moving. The goal is to find the best strategy for the cluster to swim together in a manner that’s both fast and efficient.”
Ultimately, the long-term aim is to insert micron-size (or centimeter-size if they’re being inserted in larger vessels like those in the gastrointestinal tract) artificial swimmers into the body where they could travel through the veins to deliver, for example, targeted chemotherapy drugs, or break up a blood clot without the need to thin a patient’s blood. They could also assist otherwise normal, high-quality human sperm in fertility treatments.
“In those cases, the sperm has good genetics, but maybe its tail is compromised, and so the swimmers could push the sperm toward the egg,” she says. “And that has been demonstrated by other researchers to work in a lab environment.”
Demir says it’s been gratifying to receive the CAREER award and learn that her work has earned approval from her peers. But what really drives her is the sense that her time in the lab has the potential to solve life-changing problems.
“As cliche as it sounds,” she says, “I want to use engineering to help humanity.”
About Ebru Demir
Ebru Demir is an assistant professor of mechanical engineering and mechanics in Lehigh University’s P.C. Rossin College of Engineering and Applied Science. Her research bridges thermo/fluids, biomedical engineering, and robotics, with a focus on artificial microswimmers for biomedical applications. Her research approach combines numerical simulations and experiments to investigate locomotion in complex fluids and biological environments, advancing applications such as targeted drug delivery, diagnostics, and waste elimination.
Demir’s interdisciplinary research leverages fluid mechanics/dynamics and machine learning techniques to address challenges in robotics, biomedical engineering, and advanced manufacturing. She investigates locomotion across multiple scales, from bioinspired artificial microswimmers to scaled-up intelligent robots, and contributes to flow-based medical device development through her experience in experimental design, simulations, and rapid prototyping.
Demir received both her BS and PhD in mechatronics engineering from Sabanci University (Istanbul, Turkey). She completed a postdoctoral research fellowship in the Department of Mechanical Engineering at Santa Clara University before joining Lehigh.
