Microrobots enhance algae with magnetic control for navigation

Scientists have developed tiny robots powered by microalgae. These robots are very small, even smaller than a grain of sand. Researchers at the Max Planck Institute for Intelligent Systems are making these algae-driven microbots to navigate inside the human body. They aim to improve medical technology, especially in delivering drugs directly to needed areas. The study focused on giving the microalgae a magnetic coating. This allows the robots to be steered with magnets inside the body. By adding this coating, the researchers found that the algae still swim very well, even in thick liquids. The microalgae use their flagella to move and were able to swim at impressive speeds of 115 micrometers per second. For their size, they swim much faster than Olympic swimmer Michael Phelps. Researchers coated the microalgae with magnetic nanoparticles quickly. They then tested these microbots in water and found they could control their swimming direction using magnetic fields. The team used special 3D-printed channels to see how well the microbots navigate through tight spaces. Without magnetic help, the microalgae often got stuck. But with magnetic guidance, they moved more easily and avoided obstacles. The team noted that the algae can navigate in three ways: backtracking, crossing, and magnetic crossing. This shows they can steer well in confined spaces, much like a tiny GPS. The scientists also tested the robots in thicker fluids to mimic real biological conditions. They found that while increased viscosity slowed them down, magnetic control still allowed them to move effectively, although in a zigzag pattern. This research opens new possibilities for using microrobots in targeted drug delivery. The findings were published in the journal Matter.