A research team at the University of Würzburg in Germany recently developed a photon-driven nanorobot, which is about one-fiftieth the diameter of a human hair. It can accurately track, capture, transport and release bacteria in a liquid microscopic environment, providing a new technological path for humans to directly control the microbial world.

Reports show that this type of micro-robots are aimed at micro-scale operations that are almost impossible to effectively intervene with traditional means. For biological materials such as single cells and bacteria in a liquid environment, how to achieve high-precision control has always been a major problem in scientific research, and this new result shows that tasks such as collecting and relocating bacteria are now feasible.

The research team was led by Bert Hecht, a professor at the Julius-Maximilians University Würzburg in Germany. The core solution proposed by the team is to use the weak recoil generated when a single photon is emitted to drive the movement of a micron-scale device called a "micro-drone".

According to reports, up to four plasmonic nanoantennas can be integrated inside these devices. They first absorb light with specific properties, and then re-emit photons in a directional manner; each shot will bring an extremely small recoil force, which is similar in principle to the recoil force of a bullet after it exits the barrel. Since the mass of the microrobot itself is extremely low, even if this force is very weak, it is still enough to bring high speed and rapid acceleration.

In the latest research, researchers have further reduced the size of this type of light-driven robot to less than 1 micron and simplified its control method, but still retained the propulsion mechanism based on photon recoil.

The team took advantage of the fact that the antenna wires inside the robot naturally align with the polarization direction of the incident light. By adjusting the polarization state of light, researchers can control the direction of the robot, and its forward momentum still comes from photon recoil, which makes its control method closer to the "steering plus propulsion" mode of macroscopic transportation.

Jin Qin, the first experimental scientist on the paper, said that in essence, what the team built is a nanorobot driven by light, which can lock and collect bacteria. Due to the simplified structure, the size of the robot has been reduced to a scale where it can directly enter the microbial activities, in a sense, it is like a "microscopic cleaning device".

The researchers said that this kind of nanorobot has high maneuverability and can quickly complete 90-degree turns, so it can conduct systematic and efficient scanning in a large sample area. At the same time, it can selectively capture, transport and release a considerable number of bacteria.

This means that in a controlled experimental environment, this type of device is expected to perform a "cleaning" operation on the microenvironment - collecting bacteria in a concentrated manner and moving them to a predetermined location.

Bert Hecht pointed out that this achievement vividly demonstrates that light can not only be used to observe the microscopic world, but can also be used to actively shape the microscopic world. Although the concept of "microrobot cleaners" sounds futuristic, the relevant physical principles have now been experimentally verified.

Even when carrying larger clusters of bacteria, the nanorobots retain full mobility, although their movement speed is slightly reduced. The research team believes that this stability further highlights its application potential in fields such as microbiology, biomedical research, and ultra-small scale precise control.

The relevant research paper is titled "A nanoscale robotic cleaner", co-signed by Jin Qin, Carsten Büchner, Wu Xiaofei and Bert Hecht, and was published on March 27, 2026.