Scientists at UMass Amherst report in the current issue of Small that they have genetically designed a new strain of bacteria that spins out extremely thin and highly conductive wires made up solely of non-toxic, natural amino acids
Scientists at the University of Massachusetts Amherst report in the current issue of Small that they have genetically designed a new strain of bacteria that spins out extremely thin and highly conductive wires made up of solely of non-toxic, natural amino acids.
Synthetic biowire are making an electrical connection between two electrodes. Researchers led by microbiologist Derek Lovely at UMass Amherst say the wires, which rival the thinnest wires known to man, are produced from renewable, inexpensive feedstocks and avoid the harsh chemical processes typically used to produce nanoelectronic materials.
Credit: UMass Amherst
Researchers led by microbiologist Derek Lovely say the wires, which rival the thinnest wires known to man, are produced from renewable, inexpensive feedstocks and avoid the harsh chemical processes typically used to produce nanoelectronic materials.
Lovley says, "New sources of electronic materials are needed to meet the increasing demand for making smaller, more powerful electronic devices in a sustainable way." The ability to mass-produce such thin conductive wires with this sustainable technology has many potential applications in electronic devices, functioning not only as wires, but also transistors and capacitors. Proposed applications include biocompatible sensors, computing devices, and as components of solar panels.
This advance began a decade ago, when Lovley and colleagues discovered that Geobacter, a common soil microorganism, could produce "microbial nanowires," electrically conductive protein filaments that help the microbe grow on the iron minerals abundant in soil. These microbial nanowires were conductive enough to meet the bacterium's needs, but their conductivity was well below the conductivities of organic wires that chemists could synthesize.
"As we learned more about how the microbial nanowires worked we realized that it might be possible to improve on Nature's design," says Lovley. "We knew that one class of amino acids was important for the conductivity, so we rearranged these amino acids to produce a synthetic nanowire that we thought might be more conductive."
The trick they discovered to accomplish this was to introduce tryptophan, an amino acid not present in the natural nanowires. Tryptophan is a common aromatic amino acid notorious for causing drowsiness after eating Thanksgiving turkey. However, it is also highly effective at the nanoscale in transporting electrons.
"We designed a synthetic nanowire in which a tryptophan was inserted where nature had used a phenylalanine and put in another tryptophan for one of the tyrosines. We hoped to get lucky and that Geobacter might still form nanowires from this synthetic peptide and maybe double the nanowire conductivity," says Lovley.
The results greatly exceeded the scientists' expectations. They genetically engineered a strain of Geobacter and manufactured large quantities of the synthetic nanowires 2000 times more conductive than the natural biological product. An added bonus is that the synthetic nanowires, which Lovley refers to as "biowire," had a diameter only half that of the natural product.
"We were blown away by this result," says Lovley. The conductivity of biowire exceeds that of many types of chemically produced organic nanowires with similar diameters. The extremely thin diameter of 1.5 nanometers (over 60,000 times thinner than a human hair) means that thousands of the wires can easily be packed into a very small space.
The added benefit is that making biowire does not require any of the dangerous chemicals that are needed for synthesis of other nanowires. Also, biowire contains no toxic components. "Geobacter can be grown on cheap renewable organic feedstocks so it is a very 'green' process," he notes. And, although the biowire is made out of protein, it is extremely durable. In fact, Lovley's lab had to work for months to establish a method to break it down.
"It's quite an unusual protein," Lovley says. "This may be just the beginning" he adds. Researchers in his lab recently produced more than 20 other Geobacter strains, each producing a distinct biowire variant with new amino acid combinations. He notes, "I am hoping that our initial success will attract more funding to accelerate the discovery process. We are hoping that we can modify biowire in other ways to expand its potential applications."
This research was supported by the Office of Naval Research, the National Science Foundation's Nanoscale Science and Engineering Center and the UMass Amherst Center for Hierarchical Manufacturing.
Janet Lathrop | EurekAlert!
Strange but true: Turning a material upside down can sometimes make it softer
20.10.2017 | Universitat Autonoma de Barcelona
Metallic nanoparticles will help to determine the percentage of volatile compounds
20.10.2017 | Lomonosov Moscow State University
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research