Innovation: Batteries built with genetically modified viruses
Available: Prototype by 2008
In laboratories around the world, ever-ready scientists are charging to overhaul the common battery—for which the basic science hasn't changed much in a century. Their quest: new combinations of materials yielding cells that are much smaller and last a lot longer. In these very pages ("If Popeye Were a Biochemist," November 2005), we reported on an effort to squeeze electrical juice from spinach.
The latest potential power aid: harmless viruses called bacteriophages. Researchers at the Massachusetts Institute of Technology have figured out how to genetically manipulate viruses to build structures packed with tiny conductive wires. They expect to deliver a prototype in two years, and their technology could eventually supplant today's lithium ion with thin, transparent cells boasting two to three times the energy.
Professor Angela Belcher and her team added a gene to the DNA of the virus, producing an organism with surface proteins designed to attract particles of cobalt and gold. They applied a solution containing the metal- loving viruses to a silicon slide coated with alternating layers of negatively and positively charged polymers. The viruses, which naturally repel one another, spread themselves evenly across the slide, forming ultrathin wire shapes. "The great thing about using bacteriophages as the scaffold is that the assembly and ordering are provided by the bacteriophages," says Brent Iverson, professor of chemistry and biochemistry at the University of Texas, Austin.
Finally, the virus-coated slide was dipped into a solution of charged cobalt particles. The proteins on the surface of the viruses latched onto the cobalt until each organism was completely covered in metal.
The result: a transparent film, about 10 centimeters by 10 centimeters, containing about a billion virus-sized wires—one of two electrodes that, matched with an electrolyte, would make a thin, efficient battery. It might even beat spinach.