Turkeys inspire smartphone-capable early warning system for toxins

UC Berkeley News Center ^ | January 21, 2014 | Sarah Yang

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Some may think of turkeys as good for just lunch meat and holiday meals, but bioengineers at UC Berkeley saw inspiration in the big birds for a new type of biosensor that changes color when exposed to chemical vapors. This feature makes the sensors valuable detectors of toxins or airborne pathogens.

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 Japanese and Korean.

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, the iColour Analyser, to show that a smartphone photo of the sensor’s color bands could be used to help identify chemicals of interest, such as vapor of the explosive TNT. They described their experiments in a study published today (Tuesday, Jan. 21) in the journal Nature Communications.

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Bio-inspired sensors are made from bacteriophages that mimic the collagen fibers in turkey skin. When exposed to target chemicals, the collagen-like bundles expand or contract, generating different colors. The researchers also created a mobile app to be used with smartphones to help analyze the sensor’s color bands. (Schematic courtesy of the Seung-Wuk Lee Laboratory)