A significant problem in healthcare at present is that there is no option but to dispose frequently of clothing and PPE. There is therefore a huge market need to provide reusable PPE and clothing, reducing the burden on the supply chain. The use of nanofibers is one solution to alleviate this problem.
Nanofibers
Nanofibers possess high surface area-to-volume ratio of well-interconnected nanofiber webs, fine diameters, porous structure, good mechanical performance, flexibility in surface functionalities, tuneable surface properties and high compatibility with inorganics.
In addition to their ability to incorporate active chemistry on a nanoscale surface for application in face masks and PPE, electrospun fibers are also a promising platform for air filtration. Nanofibers produced by the electrospinning technique have diameters in the range of 100 nm to 1 μm and lengths of up to kilometers. Most nanofiber mass production capabilities are based in the United States, the Czech Republic and Iran.
Facemasks
Facemasks that are comprised of nanofiber membranes allow for 99.9% filtration efficiency, in excess of standard N95 and N99 face masks. Nanofibers possess a very high surface and can also be functionalized with different chemically active groups to improve the efficiency of the masks in capturing natural nanoparticles (e.g., viruses), micron-sized particles (e.g., bacteria), and other particles (e.g., soot from diesel exhaust). For filtration in a facemask, only small amounts of nanofibers are required, on the order of less than 1 gram of fiber per square meter (gsm) filter area. This is much smaller than 20-40 gsm being used for facemasks with microfibers of diameter 2 – 20 μm.
A nanofiber filter mask sheet has recently been developed at KAIST in Korea that can maintain filtering capacity in contrast to N94 or N95 masks. Czech company Respilon Group has developed a nanofiber based ReSpimask® mask that the company states provides effective protection of the human respiratory tract against air pollution, viruses, and bacteria, as it captures 99,9% of airborne particles. According to the company, ReSpimask® is the only face mask in the world to use nanofiber technology with a three-layer membrane.
Figure 1. ReSpimask® mask.
Image courtesy of Respilon Group.
Nanocellulose face mask filters
Researchers from the Queensland University of Technology (QUT) have developed and tested a highly breathable nanocellulose material, which is able to remove virus-size nanoparticles. QUT process engineer Dr Thomas Rainey said “We have developed and tested a highly breathable nanocellulose material that can remove particles smaller than 100 nanometres, the size of viruses,” Dr Rainey said.
“I see many people wearing masks which are not tested for viruses. We have tested this material thoroughly and found it to be more efficient in its ability to remove virus-size nanoparticles than the high-quality commercially available masks we tested and compared it with.” Dr Rainey said the team also tested the new material for breathability. “By breathability we mean the pressure or effort the wearer has to use to breathe through the mask. The higher the breathability the greater the comfort and reduction in fatigue,” he said.
“This is an important factor for people who have to wear masks for long periods or those with existing respiratory conditions.
“Our tests showed the new material was more breathable than commercial face masks, including surgical masks.
effect for 14 days in normal operation in Prague public transport. Both products use have health certificates from the National Institute of Public Health and meet not only the relevant Czech national but also European standards.
Figure 2. Nanocellulose filter developed at QUT.
Image courtesy of Queensland University of Technology (QUT)
“This new material has excellent breathability, and greater ability to remove the smallest particles.” “This material would be relatively inexpensive to produce and would therefore be suitable for single-use.
“The cellulose nanofiber component is made from waste plant material such as sugar cane bagasse and other agricultural waste products and is, therefore, biodegradable. It can be made using relatively simple equipment, and so we can quickly produce large quantities of the material. We have established proof of concept as a nanoparticulate filtration material and we are currently seeking industry partners.”
Dr Thomas Rainey is working on a nanoparticle-removing new material for biodegradable anti-pollution masks, using bagasse.
Figure 3. From bagasse to a new nano-particle removing material.
Image courtesy of Queensland University of Technology (QUT)
Other PPE and textiles
Nanofiber-based filtration textiles can decompose toxic gases, kill bacteria and deactivate some viruses.
Israel-based company Sonovia Ltd. is using a patented nanotechnology process developed at Bar-Ilan University to produce masks and protective textile equipment that have proven effective in blocking the penetration of bacteria and fungus.
Figure 4. Textile filter development at Sonovia Ltd.
Image courtesy of Sonovia Ltd.
The company has sent textile samples impregnated with zinc using the same method to the Chinese Academy of Sciences in Beijing, for its lab to test the efficacy of the method against viruses. Nanoparticles of zinc, silver and graphite are all proven viral inhibitors. The facemasks developed by the company can be used repeatedly and the impregnated textile is able to maintain its anti-pathogen activity at up to 100 washes at 75° Celsius and 65 washes at 92° Celsius.
Figure 5: Nanofiber filter mask produced by Sonovia.
Image courtesy of Sonovia Ltd.
United States-based textiles developer SITA is producing masks made of SITATECH™ nanofabrics, which are comprised of nanofibers with a mechanical filtration efficiency of 99%. The company is donating the products to local hospitals. US-based G95 Inc. is also producing nanofiber based PPE that is 100% reusable. The Bioshield mask can filter our 99.75% of particles, is water-resistant and anti-bacterial.
Air-borne filtration
Air-borne virus removal filters are in high demand for preventing the spread of viruses in hospitals and public buildings. They are also widely used in biotechnology applications.
Nanocellulose (cellulose nanofibers, cellulose nanocrystals and bacterial nanocellulose) has demonstrated promise for virus filtration applications especially for large viruses ≥50 nm with potential to be enhanced further to include small viruses too, for example, by adjusting membrane thickness. The extremely small fiber diameters, high aspect ratios and tough network structures are advantageous in preparing new air filters with high performance.
Figure 7: Filter paper based on algae nanocellulose.
Image courtesy of Uppsala University.
Comprised mainly of nanocellulose fibers obtained from locally-grown Pithophora green macroalgae, the low-cost material incorporates tiny pores, the size of which has been tailored to allow water to pass through while trapping viruses and bacteria. In lab tests, sheets of the paper were shown to be over 99.999-percent efficient at removing all such pathogens in water gathered from Bangladesh’s Turag River and Dhanmondi Lake.
Nanofibers in Iran
There are several Iranian companies involved in nanofiber equipment and product production. Fanavaran Nano-Meghyas manufactures nanofiber production company and has recently sold several pieces of their production equipment to companies in China, seven of which have already been delivered and installed in this country.
Figure 7: Nanofiber production equipment.
Image courtesy of Fanavaran Nano-Meghyas.
Apart from the nanofiber production equipment, Iran has also received orders for a total of 2 million N95 respirators from different.
Nano Tar Park is an Iran-based company producing nanofiber-based filters for facemasks and exports to South Korea, Thailand and Turkey.
Further information
The Global Market for Nanofibers
Published March 2020
https://www.futuremarketsinc.com/the-global-market-for-nanofibers-to-2028/
