Cheap green makes non-toxic materials attractive

Cheap green makes non-toxic materials attractive

Such coatings might also be applied to existing steam turbines, which generate most of the world’s electricity. That could become a big retrofit business, reckons Mr Varanasi.
Nature already uses materials with nanoscale structures to great effect. The fossils that attracted the interest of Angela Belcher were formed some 500m years ago when soft-bodied organisms in the sea began using minerals to grow hard materials in the form of shells and bone. These natural products contain exquisite nanostructures, like the iridescent shells of abalone, says Ms Belcher. If creatures have the ability to make materials like that in their DNA, she concluded, it should be possible to emulate it. That is what her research group at MIT is now trying to do, using genetic engineering.
Odd though it may seem, one of Ms Belcher’s projects involves using viruses to make batteries. Viruses—usually the sort that infect bacteria and is harmless to humans—are a fairly common tool in genetic engineering. To begin with, Ms Belcher and her colleagues genetically engineer the viruses to interact or bind with materials they are interested in. As they do not have millions of years to wait, they employ what amounts to a high-speed Darwinian process: making a billion viruses at a time, selecting those with promise and repeating the process until they get a strain capable of doing what they want.
The team has developed viruses that can produce the elements of a battery, such as the cathode and anode, and used them to make small button-cells, like those that power a watch, but the process has the potential to be scaled up. What makes the technology so attractive, says Ms Belcher, is that it is cheap, uses non-toxic materials and is environmentally friendly.
Two companies founded by Ms Belcher are already making things with viruses. Cambrios Technologies is producing transparent coatings for touch screens and Siluria Technologies (Ms Belcher likes to name her companies after geological time spans) is using viruses to develop catalysts for turning natural gas into oil and plastics. There are also potential applications in solar cells, medical diagnostics and cancer treatment. And all that from an idea inspired by a sea shell.
One of the people at MIT with whom Ms Belcher is working is Gerbrand Ceder, a battery expert who felt that there had to be an easier way to find out about  materials than the present long-winded process. The information on ten different properties of a material might be scattered in ten different places.