Researchers from the University of California, Berkeley (UC Berkeley) have developed a new type of biosensor which can change its color based on the chemical vapors it was exposed to. Inspired by the turkey's changing of skin color, practical application for the sensors includes detectors of airborne pathogens and toxins.
According to the researchers led by associate professor of bioengineering, Seung-Wuk Lee, turkey skin can change its color from red to white due to the collagen which is distributed to the skin's blood vessels. The spacing between the collagen fibers varies when the blood vessels contract. The blood vessels, on the other hand, expand and contract according to the bird's emotion, for example if it is angry or excited. The amount of swelling of blood vessels alters how the light waves are scattered and this affects the color which is displayed above the turkey's head.
"In our lab, we study how light is generated and changes in nature, and then we use what we learn to engineer novel devices," Lee said to LiveScience.com.
The team also developed an app called iColourAnalyser which features a smartphone image of the sensor's color bands. The color bands could be used to detect chemicals present in the immediate surroundings including the vapor of the explosive, TNT.
The biosensors were then exposed to organic compounds such as hexane, methanol, isopropyl alcohol, at concentration of 300 parts per billion. The researchers noted that the nanostructures expanded rapidly, creating a shift in color which signifies that the biosensor was able to detect the chemicals exposed to it.
Sensors which function by giving off color readings are much simpler to use than the usual biosensors. However, color-based sensors which are being developed in various parts of the world can only detect a limited number of chemicals.
"Our system is convenient, and it is cheap to make," Lee said to LiveScience.com. "We also showed that this technology can be adapted so that smartphones can help analyze the color fingerprint of the target chemical. In the future, we could potentially use this same technology to create a breath test to detect cancer and other diseases."
The study was published in the Jan. 21 issue of Nature Communications.
