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December 28, 2012

Worms turn metal into semiconductors

Worms are useful in the garden and great for fish bait, but one of their talents has remained hidden — until now. Scientists have discovered that worms can manufacture tiny semiconductors.

At King's College in London, researchers fed an ordinary red worm, Lumbricus rubellus, soil laced with metals. The worm produced quantum dots, nano-sized semiconductors that are used in imaging, LED technologies and solar cells. The experiment was published in the Dec. 23 issue of the journal Nature Nanotechnology.

The worms created these electronic components because of their ability to detoxify their body tissue. When worms ingest the metals, proteins in their body shuttle these "toxins" to tissues called chloragogen cells that are similar to a liver in mammals. In the case of cadmium, a molecule called metallothionein attaches to it to take it away. Through several chemical steps the worm separates the metals from the organic molecules they are attached to and stores them in tiny cavities its body, but not forever: eventually whatever toxic metals the worm eats are excreted.

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