Nature's nano sensors

December 12, 2005

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When it comes to building nanostructures, nature has humanity beat hands down. Millions of years of evolution will do that for you.

Recently scientists have proposed using the nanostructured silica shells of diatoms -- a type of algae -- to control lightwaves and as templates for micro and nanodevices.

Researchers from the Italian National Council of Research, 2nd University of Naples and University of Naples "Federico II" have carried out a detailed optical study of marine diatoms and found that their shells' luminescence changes depending on the type of gas surrounding them.

In the study, they fired laser beams at the shells of Thalassiosira rotula in the presence of nitrous oxide, acetone, ethanol, air, xylene and pyridine, and measured the wavelengths of the light emitted by the shells in response. The shells turn slightly different colors depending on the surrounding gas.

The ubiquity of diatoms and the variety of shell structures, which vary by species, make them potentially useful for chemical sensing applications. They could eventually be used, for example, in devices that monitor the environment or detect chemical warfare agents.

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