Engineering microscopic algae to produce designer materials
Scientists have long prized diatoms, photosynthetic algae that abound in marine and freshwater ecosystems, because they remove large amounts of a major greenhouse gas—carbon dioxide—from the atmosphere. But another, unusual trait has recently caught the attention of materials scientists and engineers: The cell wall of this unicellular organism is made entirely of glass. More precisely, diatom shells consist of silica, or silicon dioxide, the primary constituent of glass. Many shells are ornately patterned with features just tens of nanometers in size. What's more, there are thousands of different species of diatoms, each with a unique shell design. Some look like miniature sieves, others resemble microscopic gears.