Lasers power mini machines

Scientists have built a laser-driven rotor no bigger than a pollen grain that could help power the micromachines of the future.

One minute optical windmill, fashioned from resin, has been rotated by two interlinked cogwheels. The proof-of-concept research could advance the creation of a host of microscopic tools, from medical testing equipment to new genetic engineering techniques.

Pál Ormos and Péter Galajda, of the Biological Research Centre of the Hungarian Academy of Sciences in Szeged, believe similar devices could be harnessed to bore holes in living cells, power lab-on-a-chip pumps and test the mechanical properties of DNA.

Ormos said: "This is a very simple way to make complex machines with a resolution that could go down to 100nm-200nm." The rotor and cogwheels were crafted from a light-sensitive resin, whose chemical structure was toughened by intense lasers.

Lasers held the rotor in place and then turned it at several revolutions a second. The team is already using the technology, outlined in Applied Physics Letters , in two promising areas.

It has had success drilling into living cells by attaching a laser-driven rotor to a microscopic "drill bit". This approach could be used to inject new genetic material into a cell.

In a second potential application, they have built tiny rotor-driven pumps, crucial elements of lab-on-a-chip technology. These devices, which are being researched worldwide, rapidly analyse chemical and DNA samples.