DNA coordinates assembly of glassy nanoscale structures
A team of Japanese chemists has used DNA as a scaffold to construct miniature rings and rods out of silica, the stuff of glass. According to Seiji Shinkai and his colleagues at Kyushu University in Fukuoka, Japan, this marks the first time that researchers have used the genetic material as a template for growing inorganic structures.
To make the glassy shapes, the researchers extracted DNA from the bacterium Escherichia coli and mixed it in a test tube with silica-containing precursor molecules. Because these precursors release silica as a negative ion and DNA is coated with negatively charged chemical groups, the researchers modified the DNA by decorating it with linear hydrocarbon molecules that were positively charged on both ends. One end of each hydrocarbon fixed itself to the DNA, but the other end remained free to react with silica.
Silica from the precursor molecules bound to the hydrocarbons and coated the entire DNA scaffolding, eventually forming a rod-shaped silica structure about 1 micron long and tens of nanometers wide. When the researchers coerced the bacterial DNA to assume the shape of a ring and repeated the experiment, the reaction generated silica rings. Both shapes are described in the June 21 Angewandte Chemie.
Fashioning inorganic structures using biological molecules as templates has become popular among materials scientists in recent years (SN: 7/5/03, p. 7: Microbial Materials). The strategy could offer an efficient means of creating new building blocks for use in nanotechnology.
