One main goal in the renewable energy field is to find an efficient, inexpensive way to split water into hydrogen and oxygen. The hydrogen could then be used as a fuel source for vehicles or fuel cells. Typically, an electric current breaks the water down. Now, there's a new water-splitter: a virus. MIT's Angela Belcher took her cue from plants, where special pigments capture solar energy in photosynthesis, involving the splitting of water. Belcher and her team took a harmless virus called M13. They engineered it so that one end carries a catalyst-iridium oxide. Bound at the other end are light-sensitive pigments, zinc porphyrins. The porphyrins capture light energy, and transmit it along the virus, acting as a wire, to the other end, activating the catalyst. Which splits water into oxygen and the constituents of hydrogen, a proton and electron. The work appears in the journal Nature Nanotechnology. The scientists are working on ways to recombine the protons and electrons back into hydrogen atoms and then molecules of H2. They're also seeking a cheaper catalyst than iridium. But the work could light one path to the eventual production of cleaner energy.