Gang Sun, a textile chemist at the University of California, claims to have invented a technology that could be used to develop odourless sports socks. The same technology could be used to make hospital gowns that repel bacteria and viruses, he claimed.

After use, the treated garments need only a machine wash with household chlorine bleach, to recharge the bacteria-killing capacity, he said.

Halamine technology
The technology works by attaching chlorine-containing molecules called halamines to textile fibres, using a method patented by Sun. Chlorine in the form of halamines has powerful bacteria-killing properties, used for example to disinfect swimming pools. However, unlike chlorine gas, there are no adverse effects as toxic chlorinated carbon atoms are not generated.

By sticking halamines to the cellulose fibres in cotton, the bacteria-killing effect can be bonded to the material and used repeatedly. Eventually, the chlorine is used up and can be regenerated with a wash in chlorine bleach.

The key to this invention was finding a practical way to bind the halamines to the cotton. "Obviously, one limitation is that you can't destroy the fabric during manufacture," said Sun. The finished product has to be as robust as regular textiles, and the process has to be economical. Ease of manufacture is another important factor. Most cotton mills use a durable press treatment, and halamine treatment can be added at this stage with minimal modification, according to Sun.

Commercial development
Commercial development of these bacteria-killing textiles into garments is licensed by the University of California to Seattle-based company Halosource Corporation.

The technology is being developed for a number of applications, according to Kent Foster, HaloSource director of marketing and business development. These include products for multiple use such as sportswear, kitchen tools and microbe-resistant uniforms for hospital or prison staff and single-use products, such as diapers.

One important application could be in hospital uniforms. Hospital infections are an increasing problem, and hospitals are trying to find ways to prevent infections spreading, said Sun. Medical worker uniforms might be important in spreading infection, by carrying microbes from one patient to another. Bacteria-killing uniforms could help to prevent the spread of infection, he said.

HaloSource is currently involved in technical evaluations, and discussions of product plans are under way with a number of manufacturers, said Foster. "HaloSource is working with some of the largest companies in consumer product areas, air filtration and uniforms," said Foster.

Socks in cross-country trials
The odour-free socks have been tested by volunteers, including the UC Davis cross-country running squad. Coach Sue Williams said that the men and women of the squad tested the socks through one full workout, including an eight or nine mile run. "They had pretty hard use for a day," said Williams. "They were comfortable, not irritating, and smelt very mildly of chlorine before and after," she said. "After an eight- or nine-mile run, for socks not to smell of feet is a real bonus," she added.

For more information, visit the HaloSource website at www.halosource.com.