Genetically Modified Bacteria Conduct Electricity, Ushering in New Era of Green Electronics

Genetically Modified Bacteria Conduct Electricity, Ushering in New Era of Green Electronics:

Researchers at the University of Massachusetts at Amherst have genetically modified common soil bacteria to produce nanowires capable of conducting electricity at a level that surprised even the scientists themselves. After years of skepticism that this was even theoretically possible, the practical demonstration could lead to a new generation of “green” electronics in which nanowires could be produced in plant waste, without the need for toxic chemicals.

The research, which was supported by the Office of Naval Research (ONR), goes back to a series of papers that Derek Lovley, a professor at UM Amherst, published back in 2011. Lovely overcame skeptics who claimed it was impossible for soil bacteria to conduct electricity. Brushing aside computer models indicating that it was impossible to make the bacteria into electrically conductive nanowires, Lovley demonstrated through experiments that it was indeed possible.

“Research like Dr. Lovley’s could lead to the development of new electronic materials to meet the increasing demand for smaller, more powerful computing devices,” said Linda Chrisey, a program officer in ONR’s Warfighter Performance Department, in a press release. “Being able to produce extremely thin wires with sustainable materials has enormous potential application as components of electronic devices such as sensors, transistors and capacitors.”

The bacteria that Lovley has used in his experiments are called Geobacters; they possess nanoscale protein filaments extending outward from their bodies. These protein filaments are the key to the bacteria’s growth, as they allow it to make electrical connections to the iron oxide contained in the soil where it lives. While these connections allow the Geobacter to survive, it was believed that they could never be made to conduct electricity to the extent that it would ever be useful for human interests, namely electronics.

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How to grow electronics that are one atom thick

Two atomically thin materials can form functional circuits given the right pattern. sci tech news

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Graphene sheets open like a flower’s petals when poked

Graphene sheets open like a flower’s petals when poked:

Give graphene a diamond and you’ll get a flower in return. Researchers have found that poking a sheet of atom-thick graphene with a diamond tool causes tiny ribbons to peel away from the surface, like flower petals opening.

“I don’t think anyone ever expected it,” says Graham Cross at Trinity College Dublin, Ireland, whose team made the discovery. Graphene sheets, which are made of a single layer of carbon atoms, are both superstrong andhighly flexible. Other researchers have folded graphene into origami shapes using chemical reactions and tiny tools, but no one knew that a little prompting could cause graphene to tear and fold itself on its own.

The find was an accident, discovered when the researchers were conducting an experiment to measure the friction of graphene by piercing it. Once their diamond tip punctured the sheet, they found that the energy from ambient heat was enough to cause the ribbons to keep tearing and unfolding into a tapered strip in less than a minute.

“What for me is extraordinary is that it tears,” says Annalisa Fasolino at Radboud University in Nijmegen, the Netherlands. The atoms in a graphene sheet are bonded tightly, but there is only a weak attraction between sheets when stacked, she says. However, the researchers showed that after a layer started to tear, the weak attraction between the bottom of an unfolding ribbon and the sheet below was enough for the sheet’s internal bonds to keep ripping.

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