Mosquito sitting on a flower

Novel material to be made into mosquito-bite-proof clothing

Image credit: Dreamstime

Researchers from North Carolina State University have created insecticide-free clothing which has been demonstrated to protect the wearer from mosquito bites in experiments using live mosquitoes. The researchers have formed a start-up and intend to make clothing from their novel textile materials.

They started to develop the materials using a computational model to describe the biting behaviour of Aedes aegypti: the infamous mosquito that carries viruses responsible for diseases like Zika, Dengue fever, and yellow fever.

To develop the model, the researchers investigated the dimensions of the head, antenna and mouth of the insect, and the mechanics of its bite. They used the model to predict textile materials that may be able to prevent bites, depending on their thickness and pore size.

They put the model’s predictions to the test in experiments with live, disease-free mosquitoes. A blood reservoir was surrounded with plastic materials made according to parameters produced from the model; the researchers then counted how many mosquitoes became engorged with blood.

One material they initially tested was less than 1mm in thickness but had tiny pores to prevent mosquitoes from sticking their spiky mouthparts (proboscis) through the material. Another material had a medium pore size to prevent the mosquito from inserting its head through the textile; and a third material had larger pores, but was sufficiently thick that the mosquito’s proboscis still wouldn’t be able to reach the wearer’s skin.

Next, they tested a selection of knitted and woven fabrics, which met the bite-proof parameters produced by the model, and put them to test once again. This time human volunteers were used as well as the blood reservoir; the brave participants inserted an arm covered by a protective sleeve into a cage full of mosquitoes. The material was tested against another fabric which had been treated with insecticide.

Based on their observations, the North Carolina State University researchers developed a bite-resistant, form-fitting undergarment from thin material, and a long-sleeved shirt initially envisioned as a military garment.

When a volunteer wore the base layer sitting for 10 minutes and standing for 10 minutes in a walk-in cage with 200 hungry mosquitoes, they received bites on the back and shoulders: seven bites from 200 mosquitoes. The researchers attributed the bites to the fabric stretching and deforming. By doubling the material layer around the shoulders, they were able to prevent 100 per cent of bites.

“The final garments that were produced were 100 per cent bite-resistant,” said Professor Michael Roe, an entomology expert. “Everyday clothing you wear in the summer is not bite-resistant to mosquitoes. Our work has shown that it doesn't have to be that way. Clothes that you wear every day can be made bite-resistant. Ultimately, the idea is to have a model that will cover all possible garments that person would ever want: both for the military as well as for private use.”

The team suggested similar materials could be effective against other mosquito species in addition to A. aegypti because of similarities in biology and biting behaviour. Eventually, they hope to have a model which can help design clothing for a wider range of protective functions: “There are different uses for clothing,” said first author of the 'Insects' study, Dr Kun Luan. “The idea is to have a model that will cover all possible garments that a person would ever want.”

The researchers have since formed a start-up, Vector Textiles, which has licensed the patent rights for the material. Vector Textiles intends to make clothing for sale in the US.

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