Nanotechnology can imbue textiles with eye-catching properties, but scientists and watchdogs are increasingly uncertain about the extent to which safety issues surrounding such developments have been explored. Mark Rowe reports.

According to the US-based Woodrow Wilson International Center for Scholars, more than 350 nanotech consumer products are now available, such as stain-resistant clothing, (as well as cosmetics, sunscreens and food containers).

Garments are a growth area for nanotechnology.

Some of the biggest European and US fashion houses offer garments in which nanotechnology is incorporated - supplied by the California-based nanotech fabric company Nano-Tex. 

Hugo Boss, René Lezard and Paul Stuart, are already using Nano-Tex's fabric treatment for high-end trousers, shirts and outdoor wear.

The key ingredient is a product marketed as 'Nano-Tex Resists Spills' - a treatment that repels liquids ranging from coffee and red wine to chocolate syrup and salad dressings while allowing the fabric to breathe.

The treatment is designed for use on cotton, polyester, wool, silk and rayon and works because the fabric is dipped in a solution of "nanowhiskers" - tiny fibres of cotton that are 1/1,000 of the width of a normal cotton fibre.

These fibres attach to the fabric and create a cushion of air around it, making it more wrinkle-resistant and causing liquids to bead up and roll off.

Meanwhile, the US-based company Sharper Image is marketing nanosilver-treated slippers, socks and food containers that the company says are "anti-germ, anti-mould and anti-fungus."

Antimicrobial silver particles embedded into fabric fibres have this year been applied to sports underwear by the Germany-based company Jack Wolfskin.

The nanosilver particles significantly reduce the formation of bacteria and associated unpleasant odours.

While silver is highly toxic for microorganisms it is believed to have relatively low toxicity for human tissue cells; nanosilver particles have a large relative surface area, increasing their contact with bacteria or fungi, and improving its bactericidal and fungicidal effectiveness.

Risks to consumers
Yet a number of scientists are uneasy about the rush to embrace nanotechnology.

The understanding is that nanotechnology components embedded inside an item, such as a television, provide little risk to the consumer.

But "nanowhiskers" embedded in clothing pose the potential for exposure, say some environmental health experts. Fibres can always get loose and the advice to avoid inhaling conventional fibres is well documented.

"It's a question of risk perception and benefit perception - you are going to get some people that are prepared to accept the risks of nanoparticles in return for the benefits," said Prof Lynn Frewer of the Marketing and Consumer Behaviour Group at the University of Wageningen in the Netherlands.

"If products can get into the subcutaneous part of the skin - they can go even further."

CEFIC, the Brussels-based organisation representing the European chemical industry, also acknowledges that the public must be paid far more than lip service when it comes to safety and regulation.

"We are taking it very seriously and must not make the same mistakes as have been made in other areas of technology," said Gernot Klotz, executive director for Cefic Research & Innovation.

"Advocacy is not enough by itself."

Earlier this year, CEFIC launched and funded a long-range research initiative, calling on the scientific community to submit current papers and material that discuss the risks of nano products.

"In the next two years we will learn where the gaps are and where we can be reasonably certain," he said.

Safety issues
In the United States, the Natural Resources Defense Council has criticised what it described as a "significant jump" in the number of common products containing untested and unlabelled nanoparticles, and has warned that the US regulatory body, the Environmental Protection Agency has been slow to review safety issues.

The UK-based Institute of Nanotechnology is arranging a conference that will examine the safety of nanotechnology in textiles in March next year, to be held at the Royal Society in London.

"There are some indications that there could be some health concerns, but it is still early days," said Brian McCarthy, director of TechniTex, the network group for the UK's Technical Textiles and Advanced Materials Sector, and who will be a co-author of a paper at the conference.

"For now textiles are a relatively small sector for nanotechnology but that does not mean it should not be investigated."

Britain's Chartered Institute of Environmental Health said that it would get involved in the issue as and when employers began requesting staff to wear nano-incorporated clothing as part of specific duties, while work will begin on investigating the subject at Exeter University, probably next year.

Areas under scrutiny include whether nanofibres can pass into human cells, and whether nanoparticles are lost during the use of a garment or during cleaning (most water or stain-resistant clothing sold in shops with nano elements advises consumers that the treatment will only survive 10 washes).

There is also concern from groups such as the UK Health and Safety Laboratories, an executive arm of the health and safety executive, about what might happen to nanoparticles washed out during cleaning in the sewage treatment plant.