Cotton textiles may soon be routinely produced with special compounds that eliminate dangerous microbes within minutes, and even tackle those little terrors responsible for odour, most notoriously those associated with feet.
The technique, which incorporates the use of novel chlorine compounds known as N-halamines, is simple and inexpensive, according to researchers at the University of California in Davis, headed by Dr Gang Sun, a Chinese scientist who made the initial breakthrough.
Details were revealed at the annual meeting of one of the most influential scientific organisations in the US, the American Chemical Society, late last month. One of the developers of the technology, Dr Jeffrey Williams, outlined results suggesting their formulations are faster and kill more pathogenic and odour-causing bacteria (not to mention viruses) than other "biocidal cottons".
The technique developed following work at UC Davis department of textiles and fabrics involves binding the compounds with cellulose in the cotton. They expect it to be used in a variety of clothing including sportswear, dress for healthcare workers, patient outfits, military garments, hospital/hotel bedding, handkerchiefs, dish cloths, household sponges and incontinence garments. Some general clothing items infused with N-halamines are expected to go on sale within six months, more specialised items some time later.
Research is showing that Nhalamines are particularly good at binding anything that contains cellulose, the major structural component of plants. That includes wood. Clothes are treated with N-halamine formulation in a process described by Williams as similar to that used to give a "permanent press" finish which leaves clothes wrinkle-free.
Manufacturing can, therefore, be easily adapted, while treated items can be recharged by rinsing in a dilute mixture of bleach and water. His company HaloSource, based in Seattle, has been working on commercial applications.
Anti-microbials, as they are called, have already been successfully used in kitchen utensils, notably chopping boards, which act against food bugs such as salmonella and E.coli. But Williams is quick to differentiate such products from their Nhalamine-based varieties, which have the added bonus of not being sensitising to humans, are stable at a variety of temperatures and versatile in being able to be used in many products, even cotton blended with synthetic fibres like polyester.
Chlorine, silver and copper compounds already play a big role as broad-spectrum anti-microbials, but the efficiency being achieved by new N-halamine formulations stands out. It is expected to be used firstly to counteract bacteria that cause odour, namely in sports socks. A HaloSource spokeswoman told The Irish Times its workers have been testing T-shirts and socks treated with its biocide with no adverse effects.
What's more, it acts quickly against bacteria like salmonella, E.coli and Staphylococcus, which causes untold problems in hospitals. "We can show a million time reduction in the amount of salmonella in two minutes," Dr Williams said. With other treated textiles on the market, it takes up to several hours to achieve the same kill.
The more contact with microbes, however, the less effective the new anti-microbial becomes. HaloSource estimates that a rinse to renew biocidal strength might be necessary every five washes or so. That regenerative ability makes for an anti-microbial like no other, their scientists contend. It all adds up to a new dimension to protective clothing.