Turkey skin, it turns out, can shift from red to blue to white, thanks to bundles of collagen that are interspersed with a dense array of blood vessels. It is this color-shifting characteristic that gives turkeys the name "seven-faced birds" in Korean and Japanese.
Researchers took inspiration from the way turkey skin color is altered to create a new sensor that can change color when exposed to volatile chemicals.
Credit: Photos by Valerie Burtchett
The researchers say that spacing between the collagen fibers changes when the blood vessels swell or contract, depending upon whether the bird is excited or angry. The amount of swelling changes the way light waves are scattered and, in turn, alters the colors we see on the bird's head.
Seung-Wuk Lee, UC Berkeley associate professor of bioengineering, led a research team in mimicking this color-changing ability to create biosensors that can detect volatile chemicals.
"In our lab, we study how light is generated and changes in nature, and then we use what we learn to engineer novel devices," said Lee, who is also a faculty scientist at the Lawrence Berkeley National Laboratory.
The researchers created a mobile app, called the iColour Analyser, to show that a smartphone photo of the sensor's color bands could be used to help identify toxins of interest. They described their experiments in a study to be published Tuesday, Jan. 21, in the journal Nature Communications.
Sensors that give off color readings are easier to use and read than conventional biosensors. However, the major ones in development elsewhere can only detect a limited range of chemicals and, according to the researchers, they can be very difficult to manufacture.
The researchers found that, like collagen fibers, these phage-bundled nanostructures expanded and contracted, resulting in color changes. The exact mechanism behind the shrinking or expanding phage bundles is still unclear, but it's possible that the small amount of water in the phage is reacting to the chemical vapors, the researchers said.
The turkey-inspired biosensors were exposed to a range of volatile organic compounds, including hexane, isopropyl alcohol and methanol, as well as vapor of the explosive chemical TNT, at concentrations of 300 parts per billion. The researchers found that the viruses swelled rapidly, resulting in specific color patterns that served as "fingerprints" to distinguish the different chemicals tested.
The researchers showed that the biosensor's specificity to a target chemical could be increased by genetically engineering the DNA in the M13 bacteriophage to bind with sites specific to TNT. The biosensor was then exposed to two additional chemicals, DNT and MNT, which have similar molecular structures to TNT. The engineered biosensor successfully distinguished TNT from the other chemicals with distinct color bands.
The biosensors were also able to signal changes in relative humidity, ranging from 20 percent to 90 percent, becoming redder with moister air and bluer with drier air.
The study lead author is Jin-Woo Oh, a former postdoctoral researcher in Lee's lab and now an assistant professor in the Department of Nanomaterial Engineering at Pusan National University in South Korea.
The National Science Foundation, the Defense Acquisition Program Administration and Agency for Defense Development in South Korea, Korea's Ministry of Education, Science and Technology, and Samsung helped support this work.
Sarah Yang | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy