DNA is the blueprint of all life, giving instruction and function to organisms ranging from simple one-celled bacteria to complex human beings. Now Northwestern University researchers report they have used DNA as the blueprint, contractor and construction worker to build a three-dimensional structure out of gold, a lifeless material.
Using just one kind of nanoparticle (gold) the researchers built two common but very different crystalline structures by merely changing one thing -- the strands of synthesized DNA attached to the tiny gold spheres. A different DNA sequence in the strand resulted in the formation of a different crystal.
The technique, to be published Jan. 31 as the cover story in the journal Nature and reflecting more than a decade of work, is a major and fundamental step toward building functional designer materials using programmable self-assembly. This bottom-up approach will allow scientists to take inorganic materials and build structures with specific properties for a given application, such as therapeutics, biodiagnostics, optics, electronics or catalysis.
Most gems, such as diamonds, rubies and sapphires, are crystalline inorganic materials. Within each crystal structure, the atoms have precise locations, which give each material its unique properties. Diamonds renowned hardness and refractive properties are due to its structure -- the precise location of its carbon atoms.
In the Northwestern study, gold nanoparticles take the place of atoms. The novel part of the work is that the researchers use DNA to drive the assembly of the crystal. Changing the DNA strands sequence of As, Ts, Gs and Cs changes the blueprint, and thus the shape, of the crystalline structure. The two crystals reported in Nature, both made of gold, have different properties because the particles are arranged differently.
We are now closer to the dream of learning, as nanoscientists, how to break everything down into fundament
|Contact: Megan Fellman|