A bio-inspired sensor that can change colour in response to volatile organic chemicals is reported in Nature Communications this week. The sensor, which mimics the structure of turkey skins and their ability to change the skin colour depending on their mood, could allow for the simple detection of a variety of harmful poisons and pathogens that are a threat to human health.

Many materials in nature change colours in response to stimuli, making them attractive for use as sensor platforms. However, both natural materials and their synthetic substitutes lack selectivity towards specific chemicals, and introducing such selectivity remains a challenge. Seung-Wuk Lee and colleagues created a sensing material composed of filamentous bacterial viruses that could rapidly swell and undergo distinct colour changes when exposed to volatile organic compounds. The team also demonstrate that the sensors could be tailored to respond to and detect TNT. They suggest that this tailoring could also allow for detection of other harmful chemicals.

The authors go on to show that measuring the change in colour with a simple smartphone camera gives a reliable indication of the presence and concentration of these compounds. This convenient, inexpensive, detection method combined with the ability to tune the sensor for different targets may offer an attractive method for detecting harmful and dangerous chemicals in the environment.