Standard bednets last for a year at most before they must be recoated with insecticide

Flickr/Bread for the World

[BANGKOK] Insecticide-treated bednets that retain their lethal qualities for up to five years may be possible after Thai researchers found a way of "locking in" the chemical they contain using nanotechnology.

The nets contain a nano-scale formulation of pyrethroid, the common insecticide used for bednets, with particles so small that washing does not dislodge them.

Thailand's National Nanotechnology Center (Nanotec) unveiled the nets last month (25 August) at an event at the Thailand Science Park.

Pyrethroid kills mosquiotes when they land on a treated net. It is an integral part of public health campaigns against mosquito-borne diseases such as malaria.

Sirirurg Songsivilai, executive director of Nanotec, told SciDev.Net that, because nanoparticles of pyrethroid are so small, they are incorporated more easily into the net's fibres, making them difficult to wash out.

Standard bednets last for a year at most before they must be recoated with insecticide, according to the Insecticide Research Unit at Thailand's Mahidol University.

A longer-lasting net could help reduce people's costs, as it would not need to be replaced or recoated so frequently, said Narumon Komalamisra, head of the Insecticide Research Unit. However, nano-nets are likely to be more expensive than conventional bednets, which cost around US$7-15 in Thailand.

Songsivilai said Nanotec is now ready to licence the technology. Manufacturers, he said, would test their nets in field conditions before releasing them on to the market. He added that, while no discussions about affordability for the poorest people have taken place, he believes competition between manufacturers will drive prices down.

Songsivilai said that developing this technology has been part of the centre's health and medical research programme, one of the first programmes to be prioritised under the country's nanotechnology strategy.

"The nano-based bednets have shown how sophisticated technology can be adopted to help solve the country's critical health problems," he said, adding that the centre is also willing to share the technology with other developing countries.

Charles Delacolette, coordinator of the WHO-Mekong Malaria Programme, told SciDev.Net he did not yet know whether the new nets met international standards, but that the WHO would be contacting Nanotec.