US scientists have created threads that change color when they detect a variety of gases, an advance that could help develop smart fabrics that can sniff out toxic chemicals. The threads can be read visually, or even more precisely by use of a smart phone camera, to detect changes of color due to analytes as low as 50 parts per million. Woven into clothing, smart, gas-detecting threads can provide a reusable, washable, and affordable safety asset in medical, workplace, military and rescue environments.

While not replacing the precision of electronic devices commonly used to detect volatile gases, incorporation of gas detection into textiles enables an equipment-free readout, without the need for specialised training. Such an approach could make the technology accessible to a general workforce, or to low resource communities that can benefit from the information the textiles provide.

The team used simple dyes that detect gases with acid or base properties. The method that effectively traps the dye to the thread, rather than relying so much on binding chemistry, offers more flexibility to use dyes with a wide range of functional chemistries to detect different types of gases. The tested dyes changed color in a way that is dependent and proportional to the concentration of the gas as measured using spectroscopic methods.