Nanotechnologists set viruses to work
21 February 2006
US nanotechnologists are employing viruses as construction workers to help build lithium-ion batteries and solar cells. The program follows the successful development of a method for creating ordered layers of M13 bacteriophage viruses.
The nanotechnologists from Massachusetts Institute of Technology, jointly led by Angela Belcher and Paula Hammond, took advantage of the special interaction between the polymers linear-polyethylenimine (LPEI) and polyacrylic acid (PAA) and the M13 virus. The virus was adsorbed onto a mixed layer of LPEI and PAA, and further LPEI/PAA layers were added on top. The researchers found that the viruses naturally rose to the top of the layers and arranged themselves in an ordered manner on the surface.
This effect is primarily due to LPEI, the researchers said, which diffuses between the different layers and comes between the M13 viruses and PAA, preventing them binding and forcing the viruses up towards the top layers. When the rod-shaped viruses reach the surface, electrostatic interactions cause them to line-up and form a liquid-crystal-like layer.
In previous research, Belcher and colleagues showed that the M13 virus can be genetically modified to let inorganic nanoparticles grow on its viral coat (capsid), allowing it to act as a nanowire template. Extending this concept into two dimensions, Belcher and Hammond have used their virus layers to create arrays of nanowires made of various inorganic materials, including cobalt and gallium nitride.
Thomas LaBean, professor of computer science and chemistry at Duke University, US, who has been using DNA scaffolds to produce nanowire arrays, is surprised and excited by the findings.
'There is potential for this assembly technique to effectively move viral organisation of inorganic materials from the laboratory prototype scale and up to a practical manufacturing method,' he told Chemistry World.
P J Yoo et al, Nat. Mater. (DOI: 10.1038/nmat1596)