Microelectronics Give Researchers a Remote Control for Biological Robots

Remotely controlled miniature biological robots have many potential applications in medicine, sensing and environmental monitoring. Credit: Yongdeok Kim

Scientists at the University of Illinois Urbana-Champaign, Northwestern University, and other institutions have created the first hybrid "eBiobots," which are miniature biological robots that can be remotely controlled. The eBiobots are the first to combine soft materials, living muscle, and microelectronics, according to a study published in the journal Science Robotics.

The research team, led by Rashid Bashir, a professor of bioengineering and dean of the Grainger College of Engineering at the University of Illinois, has been pioneering the development of biobots for several years. In 2012, the team demonstrated walking biobots, and in 2016, they showed light-activated biobots. However, the practical applications of these biobots were limited by the challenge of delivering light pulses to the biobots outside of a laboratory setting.

Wireless Microelectronics and Battery-Free Micro-LEDs

The solution to this problem came from John A. Rogers, a professor of materials science and engineering, biomedical engineering, and neurological surgery at Northwestern University, and director of the Querrey Simpson Institute for Bioelectronics. Rogers is a pioneer in flexible bioelectronics, and his team helped integrate tiny wireless microelectronics and battery-free micro-LEDs into the eBiobots.

"This unusual combination of technology and biology opens up vast opportunities in creating self-healing, learning, evolving, communicating, and self-organizing engineered systems," said Rogers. "We feel that it's a very fertile ground for future research with specific potential applications in biomedicine and environmental monitoring."

Powering the eBiobots

To give the eBiobots the freedom of movement required for practical applications, the researchers eliminated bulky batteries and tethering wires. The eBiobots use a receiver coil to harvest power and provide a regulated output voltage to power the micro-LEDs, said co-first author Zhengwei Li, an assistant professor of biomedical engineering at the University of Houston.

The researchers can send a wireless signal to the eBiobots that prompts the LEDs to pulse. The LEDs stimulate the light-sensitive engineered muscle to contract, moving the polymer legs so that the machines "walk." The micro-LEDs are so targeted that they can activate specific portions of muscle, making the eBiobot turn in the desired direction.

Computational Modeling and 3D Printing

The researchers used computational modeling to optimize the eBiobot design and component integration for robustness, speed, and maneuverability. Illinois professor of mechanical sciences and engineering Mattia Gazzola led the simulation and design of the eBiobots. The iterative design and additive 3D printing of the scaffolds allowed for rapid cycles of experiments and performance improvement, said Gazzola and co-first author Xiaotian Zhang, a postdoctoral researcher in Gazzola's lab.

Future Applications

The design of the eBiobots allows for possible future integration of additional microelectronics, such as chemical and biological sensors, or 3D-printed scaffold parts for functions like pushing or transporting things that the biobots encounter, said co-first author Youngdeok Kim, who completed the work as a graduate student at Illinois.

The integration of electronic sensors or biological neurons would allow the eBiobots to sense and respond to toxins in the environment, biomarkers for disease, and other possibilities, the researchers said.

"In developing a first-ever hybrid bioelectronic robot, we are opening the door to many potential applications in medicine, sensing, and the environment," said Bashir.

Journal Information: Yongdeok Kim et al, Remote control of muscle-driven miniature robots with battery-free wireless optoelectronics, Science Robotics (2023). DOI: 10.1126/scirobotics.add1053