Researchers build light driven nanorobots that hunt down and collect bacteria

[HitmanMatt53]

A team at the University of Wurzburg has built microscopic robots, roughly fifty times smaller than the width of a human hair, that can navigate through liquid using nothing but light and then capture, transport and release bacteria at a chosen location. Lead experimental scientist Jin Qin describes the result plainly as a light driven nanorobot that can track down and collect bacteria, and the team says simplifying the underlying design is what finally got them down to a size small enough to operate directly inside the microbial world rather than just alongside it.

The steering mechanism relies on polarization controlled photon recoil, which is a fairly elegant way of saying that carefully shaped and polarized light physically pushes the tiny robot in a controllable direction as photons bounce off it. That approach lets the devices make remarkably tight ninety degree turns, which in turn helps them scan a sample methodically rather than just drifting around randomly hoping to bump into something useful. Once a nanorobot encounters bacteria, an attractive thermophoretic force draws the target in close enough to be captured and carried off.

Under controlled laboratory conditions the robots functioned essentially as microscopic cleaning crews, gathering bacteria from one region of a sample and depositing them at a specifically chosen spot elsewhere, all without any onboard motor or battery of any kind. Co-author Bert Hecht frames the broader significance nicely, noting this is a striking example of how light can be used not just to observe the microscopic world through a microscope lens but to actively reach in and reshape it.

Manipulating objects at this scale has been a long standing goal across microbiology and materials science, since so much of what happens biologically at the cellular level is functionally invisible and untouchable to anything built at human hand scale. A tool that can precisely relocate specific microbes without physically touching a sample with any external instrument opens up possibilities for controlled experiments that were previously either impossible or required much blunter, less precise techniques than researchers would ideally want to work with.

It is still very early days for any kind of practical application. The published work, out in Nature Communications, is squarely a proof of concept demonstration rather than anything close to a deployable tool, and scaling from single nanorobots in a lab dish to anything resembling a useful array operating at meaningful throughput is a substantial engineering challenge that has not been solved yet by anyone in this space.

Tiny robots powered by light can hunt down and collect bacteriawww.sciencedaily.com