Scientists at the Max Planck Institute are making progress on the way to tiny robots to navigate the human body.
Tiny medical robots that can navigate through the human body with precision are becoming a reality, thanks to researchers at the Max Planck Institute for Intelligent Systems. The foundation of this breakthrough lies in microalgae—single-celled organisms that are only a millionth of a meter in size and naturally swim through their environment. Propelled by two whip-like flagella at the front, their rapid movements resemble breaststroke swimming.
To steer the microorganisms with precision, the research team coated them with a magnetic material. External magnetic fields, generated by two permanent magnets, guide the algae’s swimming direction. The lead researchers, Birgül Akolpoglu and Saadet Fatma Baltaci, had previously tested this principle with bacteria-based micro-swimmers, using rare earth permanent magnets.
Faster Than Olympic Swimmers
The modified microalgae were then tested in an environment similar to human tissue: narrow spaces in a viscous liquid with a density comparable to mucus. The results were striking: The additional load barely affected the swimming robots. Their average speed, according to the researchers, was 115 micrometers per second—around 12 body lengths per second. For comparison, an Olympic swimmer like Michael Phelps, who can also use his legs for propulsion, reaches about 1.4 body lengths per second. The magnetic control even enhanced the algae’s swimming performance, as without it, the algae would often get stuck in the confined space and return to the starting point. Akolpoglu compares the system to a tiny GPS.
The researchers now plan to further optimize their development. These findings could pave the way for applications such as the targeted, biocompatible delivery of drugs and could also be used in other scenarios where microrobots need to be guided through hard-to-reach environments.
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