The Ceramic Art of Algae

No one knows how tiny algae called diatoms build glasslike silica laceworks within their cell walls, but researchers are closing in on the secret. In tomorrow's Science, biochemists report new clues--silica-forming proteins dubbed silaffins. The finding tantalizes scientists who envy mother nature's sophisticated handiwork.

To make any ceramic, from a dinner plate to a toughened drill bit, engineers and artisans now have to mix powders, press them into molds, and fire them in furnaces. Yet there are no furnaces in sight when a developing child grows bone or a diatom drapes itself in silica lace.

Nils Kröger and colleagues at the University of Regensburg in Germany suspected that diatoms make proteins that orchestrate the initial phase of biosilica formation. After extracting organic material from diatom samples, the researchers isolated three proteins--small, closely related silaffins--that could instigate the precipitation of silica in a test tube.

Kröger wonders whether silaffins might be forming molecular frameworks that then guide the growth of the silica. However diatoms create their silica patterns, it's a trick materials scientists would like to emulate. Diatom-like methods for making intricately shaped ceramics might yield photonic materials, whose internal arrangements of solid and space could select and confine wavelengths of light for communication or computing.