Hot summer weather, stressful situations, working in restrictive PPE and intense workouts can produce unpleasant sweaty odours.
But what if clothing could cover up these embarrassing smells with a burst of fragrance? Now, researchers have modified cotton fabric to emit a lemony citronella aroma upon contact with sweat. The report can be found in ACS Applied Materials & Interfaces.
In recent years, scientists have developed smart fabrics that react to stimuli such as light, temperature or mechanical stress and respond in certain ways, such as by changing colour or conducting an electrical signal. Researchers have also explored different methods to release fragrances from fabrics. Carla Silva, Artur Cavaco-Paulo and colleagues from the University of Minho’s Centre of Biological Engineering, Portugal, wanted to develop and compare two new strategies for releasing a fragrance – β-citronellol, a lemongrass-derived scent used in some insect repellents – from cotton fabric in response to sweat.
The first approach involved an odourant-binding protein (OBP) found in pigs’ noses that binds to β-citronellol and other scent molecules. To the OBP, the researchers attached a protein domain, called a carbohydrate-binding module (CBM), that binds to cotton. In their second strategy, the researchers packaged the fragrance in liposomes that displayed CBMs, which anchored the lipid carriers and their cargo to the fabric. The team exposed the modified cotton fabrics to an acidic sweat solution, and the low pH of the simulated perspiration caused the OBP and liposomes to release β-citronellol. Comparing the two strategies revealed that the OBP released a quick burst of scent, while the liposomes showed a slower, controlled release. The liposomes could also hold more fragrance than the other approach. The two strategies could prove useful for different clothing applications, the researchers say.
Due to cotton being a cellulose fibre, this was an effective fabric to use in the binding process of the protein domain, but the researchers tell WTiN that a system can also be designed to bind synthetic fabrics renowned for harbouring odour in garments, such as polyester and/or polyamide (nylon).
The OBP they used binds to any kind of fragrance. “The future would be to try to find companies willing to use these fusion proteins,” says Cavaco-Paulo.
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