Silver-Packing Bacteria
While silver is usually toxic to microbes, such that silver compounds make effective bactericides, these bugs apparently can survive silver-rich environments because they gather all the metal in their systems into small granules which they store at the edge of their cells.
"It's a very clever trick," said Klaus of the Department of Materials Science at Uppsala University.
By culturing the bacteria in high concentrations of silver salts, the research team got them to synthesize single, silver-based crystals with well-defined shapes, including equilateral triangles and hexagons. The small size and composite nature of the silver crystals will make them interesting to scientists working in the field of nanotechnology. Nanophase materials have novel properties not seen in normal, large-scale crystalline solids of the same chemical composition. Often, they have unusual electrical and optical properties because of the precise way in which their atoms are arranged.
Traditional approaches to fabricating materials with dimensions on the nanometer scale tend to be costly and inefficient, so bacteria that can grow such particles could prove very useful. The Uppsala team suggests it may be possible to produce new types of metal films and coatings that have their properties "tuned" according to the way the bacteria are cultured.
This report of "organically grown" silver crystals provides new insights into metal-microbial interactions and has implications for biochemical, environmental, and industrial applications. This work was supported by the European Union and the Angström Solar Center at Uppsala University.
For more information: Tanja Klaus, Department of Material Science, The Angstrom Laboratory, Uppsala University, PO Box 534 SE- 751 21, Uppsala, Sweden. Tel: +46 18-471-7234. Fax: +46 18-500-131. Email: Tanja.Klaus@angstrom.uu.se.