The U.S. Navy Has Created Genetically Modified Bacteria to Serve as Nanowires in Tiny Devices

by Darien Cavanaugh. Cavanaugh is a contributor for War is Boring and Reverb Press. He serves on the Board of Directors for Auntie Bellum.

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Bottom up growth of ZnO nanowires at the University of Cambridge Nanoscience Centre (Photo: Engineering at Cambridge/Flickr).

The Office of Naval Research (ONR) announced in mid-August that a team of microbiologists it sponsors at the University of Massachusetts Amherst succeeded in genetically modifying a common bacteria so it can be effectively used as wires in nanotechnology. The researchers, led by Dr. Derek Lovley, have been working on ways of addressing the “growing appetite for technology that is smaller, faster and more mobile and powerful than ever before”. To do so, they looked to a metal-eating bacteria abundant in many soils.

“The centerpiece of Lovley’s work is Geobacter, a bacteria that produces microbial nanowires — hair-like protein filaments protruding from the organism — enabling it to make electrical connections with the iron oxides that support its growth in the ground,” reads a recent report from Warren Duffie Jr. of the ONR. “Although Geobacter naturally carries enough electricity for its own survival, the current is too weak for human use, but is enough to be measured with electrodes.”

Geobacter sulfurreducens (Photo: United States Department of Energy).

To enhance the Geobacter’s conductivity, Lovley and his associates altered its genetic composition by replacing two of its amino acids with tryptophan. “As we learned more about how the microbial nanowires worked, we realized it might be possible to improve on nature’s design,” says Lovley. “We rearranged the amino acids to produce a synthetic nanowire that we thought might be more conductive. We hoped that Geobacter might still form nanowires and double their conductivity.”

To suggest that things went better than expected would be an understatement. While Lovley hoped to merely double the conductivity of the Geobacter, it turns out the genetically modified bacteria ended up being 2,000 times more conductive than their natural counterparts, according to the ONR. The new Geobacter were also stronger and much, much smaller. The microbial nanowires in the modified bacteria have a diameter of only 1.5 nanometers. As a point of comparison, a human hair is roughly 80,000 to 100,000 nanometers wide.

Geobacter Nanowires Present Myriad Possibilities for Potential Technological Advancement
Numerous uses for Geobacter are already in research and development stages, for both the civilian and military sectors. “Geobacter species are of interest because of their novel electron transfer capabilities, the ability to transfer electrons outside the cell and transport these electrons over long distances via conductive filaments known as microbial nanowires,” explains the Geobacter Project’s website, which serves as the online home for Lovley’s research. “Geobacter have a major impact on the natural environment and have practical application in the fields of bioenergy, bioremediation, and bioelectronics.”

For instance, the site explains, Geobacter can play an important role in bioremediation and environmental restoration by breaking down petroleum-based contaminants polluting groundwater. In terms of bioenergy, Geobacter can also help produce methane, a sustainable biofuel.

Using Geobacter for the development of new fuel sources is one area where the civilian and military research overlap. “From a military perspective, the nanowires could feed electrical currents to specially engineered microbes to create butanol, an alternative fuel,” writes Duffie. “This would be particularly useful in remote locations like Afghanistan, where fuel convoys are often attacked and it costs hundreds of dollars per gallon to ship fuel to warfighters.”

At a time when automated and remote controlled combat operations are becoming increasingly prevalent, a genetically-modified nanotech bacteria’s battlefield uses could go well beyond supply logistics, of course. “Lovley’s nanowires also may play a crucial role in powering highly sensitive microbes (which could be placed on a silicon chip and attached to unmanned vehicles) that could sense the presence of pollutants, toxic chemicals or explosives,” Duffie adds. The bacteria’s natural sensitivity to chemicals could also make it useful in certain medical applications, another area where both private and public institutions are investing in research.

Both Lovley and Dr. Linda Chrisey, a program officer in ONR’s Warfighter Performance Department, hope the newly developed “ultra-miniature nanowires” can be installed in medical sensors. If so, their sensitivity to pH changes could provide vital information about a patient’s heart and kidney function.

Greener Than Your Average Nanowire
An additional benefit of using the modified bacteria for creating nanowires is that they’re much greener than traditional nanoelectronic materials. Lovley says the engineered microbial wires can be produced using renewable energy like solar energy, carbon dioxide, or plant waste. They are also comprised of non-toxic, natural proteins and do not require the “harsh chemical processes” used to create synthetic nanowires.

Scientists have been exploring ways to create cleaner energy from bacteria and other microbes for years, and Lovley has been on the forefront of that research. In 2009 Time magazine recognized his work on “The Electric Microbe” as one of the “50 Best Inventions” of the year. That strand of his genetically modified Geobacter was only eight times more efficient at producing energy that it’s natural counterpart, falling far short of the newly developed strand with its 2,000 fold increase in conductivity.

ZnO nanowires, grown by Molecular Beam Epitaxy with Au catalysts, at London Centre for Nanotechnology. Width of the image ~5.5 microns (Photo: Ivan Isakov, Creative Commons Attribution-Share Alike 3.0 Unported).

ZnO nanowires, grown by Molecular Beam Epitaxy with Au catalysts, at London Centre for Nanotechnology. Width of the image ~5.5 microns (Photo: Ivan Isakov, Wikimedia Commons, Creative Commons Attribution-Share Alike 3.0 Unported).

 
The Pentagon Has Big Plans for Nanotechnology
Lovley and his team’s breakthrough comes at a crucial time for nanotechnology, particularly in regard to the Pentagon’s plans for the future of the U.S. military. According to a report titled “Joint Operating Environment 2035” released by the Joint Chiefs of Staff in late July, only a few weeks prior to Lovley’s announcement, nanotechnology will play an important role in U.S. combat operations by 2035.

The report gives a rundown of several menacing-sounding threats the Pentagon predicts lie just over the horizon, including “Threatened US Territory and Sovereignty”, “Antagonistic Geopolitical Balancing”, “Disrupted Global Commons”, and “A Contest for Cyberspace”, among others. A primary concern of the report is the proliferation of advanced technology, such as 3D printers and drones, among international terrorist organizations and crime syndicates. The Islamic State’s use of drones being an obvious example. (See also Darien Cavanaugh, “We’re Rapidly Approaching a Terrifying New Age of Automated Warfare“, offiziere.ch, 12.08.2016).

To stay one step of ahead of these purveyors of “privatized violence”, to borrow a term from the report, will require constant advances not just in technology but in technology that cannot be easily mimicked, captured, or appropriated. The Pentagon hopes an increased emphasis on multidisciplinary scientific research can keep U.S. forces ahead of the curve. “By 2035, many important scientific advances will result from an emphasis on how differing phenomena interact and how seemingly diverse technological domains relate to one another,” the report states. “They will frequently take place where two or more disciplines converge, particularly in the rapidly evolving areas of biology, robotics and autonomy, information technology, nanotechnology, and energy.”

The “exploitation of unique material properties at the nanoscale” is one of five key fields of research on which the report focuses. “The ability to make and modify materials at the nanoscale will allow manufacturers to take advantage of many new properties,” write the authors. “Anticipated advances in nanomaterial technologies (combined with parallel improvements in metamaterials) suggest that more complex composites and bespoke materials will emerge with properties engineered precisely to optimize performance.”

Another area of research underscored in the report is the “Emergence of micro/nano-satellites and near-space capabilities”. That section reads like something straight out of a DARPA madcap fantasy:

Micro/nano-satellites, as well as ultra-high altitude aircraft and balloons, will continue to replace large satellites because they are considerably cheaper and faster to build and launch. These advances will likely lead to improved reliability, with networks of small satellites and stratospheric swarms performing the tasks previously reserved exclusively for large satellites.”

“Nano” is an accepted term but nonetheless somewhat of misnomer in regards to the small satellites the Joint Chiefs refer to in the report, but the passage on them in the report highlights the Pentagon’s intentions of going as small as possible with some technologies. Picosatellites or femtosatellites would be better examples of tiny satellites.

Lovley’s ongoing research with Geobacter will certainly continue to play a prominent part in the Pentagon’s vision for nanotech’s increasing role in the U.S. military. It was Lovley and his colleagues, after all, who first isolated Geobacter metallireducens in 1987.

This entry was posted in Darien Cavanaugh, English, Technology.

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