Patent rights to mosquito-resistant clothing developed at NC State has been licensed by startup company Vector Textiles.

By Laura Oleniacz

North Carolina State University researchers have created insecticide-free, mosquito-resistant clothing using textile materials they confirmed to be bite-proof in experiments with live mosquitoes. They developed the materials using a computational model of their own design, which describes the biting behavior of Aedes aegypti, the mosquito that carries viruses that cause human diseases like Zika, Dengue fever and yellow fever.

Ultimately, the researchers reported in the journal Insects that they were able to prevent 100 percent of bites when a volunteer wore their clothing — a base layer undergarment and a combat shirt initially designed for the military — in a cage with 200 live, disease-free mosquitoes. Vector Textiles, an NC State startup company, has licensed the related patent rights and intends to make clothing for commercial sale in the United States.

The researchers think their computational model could be used more widely to develop clothing to reduce transmission of diseases.

“The fabric is proven to work — that’s the great thing we discovered,” said study co-author Andre West, associate professor of fashion and textile design at NC State, and director of Zeis Textiles Extension for Economic Development. “To me, that’s revolutionary. We found we can prevent the mosquito from pushing through the fabric, while others were thick enough to prevent it from reaching the skin.”

To develop the computational model to design textile materials that could prevent A. aegypti bites, researchers investigated the dimensions of the head, antenna and mouth of A. aegypti, and the mechanics of how it bites. Then, they used the model to predict textile materials that would prevent bites, depending on their thickness and pore size. Researchers said they believe the materials could be effective against other mosquito species in addition to A. aegypti because of similarities in biology and biting behavior.

“There are different uses for clothing,” said the study’s first author Kun Luan, postdoctoral research scholar of forest biomaterials at NC State. “The idea is to have a model that will cover all possible garments that a person would ever want.”

Testing The Model

To test the accuracy of their model, the researchers tested the materials predicted to be bite-proof. In experiments with live, disease-free mosquitoes, the researchers surrounded a blood reservoir with plastic materials made according to parameters predicted by the model. They then counted how many mosquitoes became engorged with blood.

One material they initially tested was very thin — less than one millimeter thick — but had a very small pore size to prevent the mosquito from sticking its mouth parts, or proboscis, through the material. Another material had a medium pore size to prevent the mosquito from inserting its head through the textile far enough to reach the skin; and a third material had larger pores, but was sufficiently thick that the mosquito’s mouth still couldn’t reach the skin.

In a subsequent test, the researchers chose a series of knitted and woven fabrics that met the bite-proof parameters determined by the model, and validated they worked in experiments using both the blood reservoir and human volunteers. The researchers tested the number of bites received by volunteers when study participants inserted an arm covered by a protective sleeve into a mosquito cage. The researchers also compared the fabrics’ ability to prevent bites and repel mosquitoes to fabrics treated with an insecticide.

From what they learned in early experiments, researchers developed the bite-resistant, form-fitting undergarment made with a thin material, as well as a long-sleeved shirt, which was initially envisioned as a combat shirt for the military.

When a volunteer wore the garments sitting for 10 minutes and standing for 10 minutes in a walk-in cage with 200 hungry mosquitoes, the volunteer found the combat shirt was 100-percent effective at preventing bites. In the first trial testing the base layer, the volunteer received bites on the back and shoulders — seven bites from 200 mosquitoes. The researchers attributed the bites to the fabric stretching and deforming, so they doubled the material layer around the shoulders, and were ultimately able to prevent 100 percent of bites. They also tested the clothing for comfort, and to see how well it trapped heat and released moisture.

Results

“The final garments that were produced were 100-percent bite-resistant,” said Michael Roe, William Neal Reynolds Distinguished Professor of Entomology at NC State. “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 study, “Mosquito-textile physics: A mathematical roadmap to insecticide-free, bite-proof clothing for everyday life,” was published online July 13, 2021, in the journal Insects. It was authored by Luan, Roe, West, Charles Apperson, Marian McCord, Emiel DenHartog, Quan Shi, Nicholas Travanty, Robert Mitchell, Grayson Cave, John Strider and Youngxin Wang from NC State University; and Isa Bettermann, Florian Neumann and Tobias Beck from Aachen University, Germany. The study was supported by the National Science Foundation, the Department of Defense Deployed War Fighter Program, Natick Contracting Division of the U.S. Department of Defense, the Chancellor’s Innovation Fund at NC State, the Southeast Center for Agricultural Health and Injury Prevention, PILOTS and the NC Agriculture Research Experiment Station.

Editor’s Note: Laura Oleniacz is Public Communications Specialist at NC State News Services.

July/August 2021

Rieter’s Comber E 90 offers consistent quality thanks to reliable, real-time information with Rieter Quality Monitor.

TW Special Report

Switzerland-based Rieter reports that its latest comber E 90 achieves a high level of productivity. Combined with its high raw material utilization capability and economical energy consumption, the lowest production costs per kilogram of combed sliver may be achieved.

In addition to these E 90 capabilities, Rieter’s customer Brazil-based Norfil S.A. Indústria Têxtil was particularly impressed by the continuous monitoring of the sliver quality. This makes unpleasant surprises in the yarn a thing of the past.

The comber E 90 produces up to 100 kilograms of combed sliver per hour. The high combing speed of 600 nips per minute, as well as the stable and fault-free running behavior of the machine, enable this high standard of productivity. In addition, the E 90 delivers all quality levels with high consistency from yarns with low noil extraction to fine yarns in a class of their own, according to Rieter.

High Flexibility,

Consistent Quality

Flexibility was also an important factor for Norfil when it was considering the E 90 comber. Norfil is a family-owned business in the state of Paraiba founded in 1989. Thanks to continuous investments in technology and automation, the company now produces 2,400 tons of yarn per month. Using raw material from its own cotton plantation, Norfil manufactures high-quality yarn for the apparel industry, with combed cotton yarns as its main product. The company was looking for a comber that could not only deliver consistently high quality, but would also have the capability to produce different quality levels with high consistency. Norfil’s new Rieter E 90 comber meets these expectations. The operating unit is very easy to use, which enables Norfil to flexibly change the quality requirements. The new technology components developed for the E 90 significantly reduce the noil extraction and lead to improved raw-material utilization.

Real-Time Information On Sliver Quality

Production at Norfil takes place with total control over the sliver quality thanks to the Rieter Quality Monitor (RQM) technology. This proven Rieter draw frame technology is now also fully integrated in the E 90 comber. A sensor continuously monitors the sliver quality produced by the comber and constantly delivers exact and reliable information regarding the current quality level. This allows deviations in sliver weight and sliver evenness to be detected early. As a result, unpleasant surprises in the yarn due to changed settings in the comber are a thing of the past at Norfil.

“The new comber E 90 takes many things off our hands so that we can concentrate on our priorities,” said Norfil Owner Fabio Borger. “This is mainly due to the Rieter Quality Monitor (RQM). It is easily adjustable, and we can trust the settings. The comber delivers the promised quality very consistently at a high productivity rate.”

Quick Change Of Noil Level

Another requirement of Norfil for its new comber was the ability to quickly change the noil level. Using Rieter’s E 90, Norfil can quickly change from 14 percent to 24 percent, which extends the company’s working range and saves raw material. The company can now produce sliver with a low noil level of 14 percent with maximum consistency for Ne 30 at a rate of 550 nips per minute — with enough headroom to easily accelerate to 600 nips per minute if needed (see Figure 1). Thanks to the huge noil savings with the E 90, Norfil also managed to cut costs while maintaining quality.

Rieter has developed new technology components for the E 90 that significantly increase the range of applications of the top comb and circular comb. With this new development, it is possible to reduce the noil extraction amount by 3 percent without the need to change the settings of the top comb and circular comb. As a result, raw material utilization is improved significantly with low noil extraction. Maximum output remains consistent even when producing high-quality yarns.

Norfil is very satisfied with the ongoing support from Rieter technicians throughout the E 90 installation project. In cooperation with Rieter technologists, Norfil was able to implement new ideas, resulting in a new combing process designed for their specific needs. The comber E 90 is the best solution for Norfil and the company has already ordered the next batch of combers.

July/August 2021