Researchers at Tufts University’s School of Engineering in Massachusetts, US, have developed biomaterial-based inks that can be printed onto wearable textiles, which respond to and quantify chemicals released from the body, such as sweat, or in the surrounding environment by changing colour.

The bio-inks can be screen printed on textiles such as clothes, shoes and face masks in complex patterns and at high resolution, to provide a detailed map of human response or exposure.

Fiorenzo Omenetto, professor of engineering at Tufts’ School of Engineering, said: “The use of novel bioactive inks with the very common method of screen printing opens up promising opportunities for the mass-production of soft, wearable fabrics with large numbers of sensors that could be applied to detect a range of conditions.

“The fabrics can end up in uniforms for the workplace, sports clothing, or even on furniture and architectural structures.”

The components that make the sensing garments possible are biologically activated silk-based inks, explains Tufts, which can be modified by embedding various ‘reporter’ molecules, such as pH sensitive indicators or enzymes like lactate oxidase to indicate levels of lactate in sweat – the former could be an indicator of skin health or dehydration, while the latter could indicate levels of fatigue of the wearer.

“The screen printing approach provides the equivalent of having a large, multiplexed arrangement of sensors covering extensive areas of the body, if worn as a garment, or even on large surfaces such as room interiors,” added Giusy Matzeu, research assistant professor of biomedical engineering at Tufts School of Engineering.

“Coupled with image analysis, we can obtain a high-resolution map of colour reactions over a large area, and gain more insight on overall physiological or environmental state.”