Scientists say they have found a way to convert the delicate exoskeleton of single-cell algae into silicon, the gold standard of electronics.

The ability to replicate these nanoscale structures could yield new applications in electronics from ultra-precise sensing devices to optoelectronics, the scientists say.

The study by Zhihao Bao and colleagues from the Georgia Institute of Technology is published today in the journal Nature and contributes to a growing body of research on new materials that can be manipulated on an atomic scale.

The researchers essentially transformed the glass-like silica in the algae cell walls into the element silicon, a better semiconductor.

Silica, or silicon dioxide, is formed when silicon and oxygen, the two most common elements in Earth's crust, come into contact with each other.

"This new work shows that glass can be transformed into silicon at relatively low temperatures while preserving a complex structure," says David Norris, a professor in chemical engineering at the University of Minnesota who writes a commentary in the same issue of the journal.

"Because glass structures are very common, both in natural and man-made materials, this is a significant new trick," he says.

The recipe for silicon

The researchers started with the silica-containing cell walls of algae called diatoms.

They then exposed the silica to magnesium gas at 650°C to obtain a solid in which silicon is partially trapped by magnesia, or magnesium oxide.

Because the temperatures needed are relatively low, Norris says "the original shape of the silica is largely preserved".

The magnesia is then removed by bathing the sold in hydrochloric acid, leaving behind a silicon replica with all the intricate architecture of the original template intact.

Compared to the compound silica, silicon is a far better semiconductor for electronics applications. The complicated structures borrowed from the diatoms are also well-suited for certain technical applications.

To test the new materials, Bao and his colleagues attached minuscule wires to a single diatom replica and used it as a microsensor.

The results suggest that the structure provides a much more efficient sensor for certain gases than conventional techniques.