Léo RamosWater-repellent fabric with bactericide and silver nanoparticlesLéo Ramos
The use of nanotechnology in clothing has reached the production line. There are at least three textile companies in Brazil—one in São Paulo State and two in Santa Catarina—that offer clothing specifically for physical activity and fabrics with antimicrobial properties for health professionals. In Campinas, a city northwest of São Paulo, EPI Saúde, a startup housed in the business incubator of the Agency for Innovation (Inova Unicamp) is making fabrics with silver nanoparticles (which confer bactericidal properties) and fluorocarbon molecules (which make them water repellent). This type of fabric already exists in the market and is now being tested at the Hospital das Clínicas of the University of Campinas (HC-Unicamp) in the form of lab coats, jackets and other clothing for health professionals. It can also be used in sheets, pillow cases and patient clothing.
The project is a result of combining the interests and experience of the founder of EPI Saúde, Paulo Formagio, owner of another company that already produces personal protective equipment (PPE) for use in agriculture, and medical endocrinologist Laura Sterian Ward, of Unicamp’s School of Medical Sciences. “I realized there was an opportunity in the healthcare area,” says Formagio. “After analyzing scientific studies on hospital contamination, I researched medical information at Unicamp. That search showed the need for personal protective equipment that was more efficient than equipment made from non-treated fabrics.”
Ward, for her part, says she decided to get involved in the project after her daughter, currently in her sixth year of studying medicine, said she would like to go to Liberia, Africa, to help treat patients infected with Ebola. “I was terrified,” she says. “The PPE that doctors and nurses typically used to deal with Ebola infected patients was astronaut-like, that is, hot, uncomfortable, and difficult to move around in. In the healthcare area, we do not have clear regulations regarding protective equipment and we use only white coats, gloves and ordinary masks, which are also PPEs with no special properties.”
Ward notes that health professionals are always subject to contamination. Depending on the type of procedure, they are exposed to patients’ bodily fluids and chemicals (such as chemotherapy) that can cause infections, allergies, and other problems. “Using appropriate PPE protects the professional, the patient and the community,” says Ward, the principal investigator for the project. The risks of hospital infections are not insignificant. There is very little epidemiological data in Brazil on the prevalence of hospital infections. One of the most cited studies even today, for lack of others, is a 1995 study that investigated 99 tertiary hospitals in Brazil and found a hospital infection rate of 15.5%. “The PPE we are developing can help reduce this rate.” Hence the convenience of adding water-repellent and antimicrobial properties to fabrics used every day in hospitals (see Pesquisa FAPESP Issues nº 130 and 206).
To add these properties to the fabric, the textile material is immersed in a solution containing fluorocarbon and silver nanoparticles, at a temperature between 190ºC and 200ºC. After the fabric passes through a dryer, it can then be used to make uniforms, lab coats and jackets. According to Paulo Formagio, the nanoparticles can be added directly to fibers, separately, or to the fabric. “This can be done to any type of textile, but in this project we used two types of fabrics: one that was a blend of 50% cotton and 50% polyester, and another that was only polyester,” he says. Fluorocarbons have the ability to repel fluids. Silver fights microorganisms by piercing the cell membranes of the bacteria and releasing ions into them, thereby preventing them from reproducing.
Paulo S Formagio / EPI Saúde EPI Saúde’s production line in Campinas: process of treating fabric with fluorocarbon and silver nanoparticlesPaulo S Formagio / EPI Saúde
Lab coats, jackets and uniforms made with nanoparticle-coated fabrics were tested by 22 health professionals in the Infectious Diseases ward at Unicamp’s Hospital das Clínicas and by eight biologists from the Department of Clinical Medicine. “We first prepared a questionnaire for technicians and nurses,” says Ward. “We wanted to know what their awareness of risk was and how they viewed the use of PPE.” The garments were then supplied and used for three months. After the three months, the professionals were given a new questionnaire that evaluated the usability of the clothing (ease of wear, suitability for work routines, etc.).
The Hospital’s clinical director and an infectious disease specialist, Plínio Trabasso, monitored the entire experiment. “Users had a favorable opinion of the equipment in terms of usability, comfort and tolerance to variations in temperature,” he says. “That is to say, the PPE did not interfere with their daily activities, such as bathing patients or applying dressings, among other tasks.” The clothing can be laundered from 50 to 70 times without affecting the nanoparticles. After that, the fabric becomes degraded and it is not feasible—either technically or economically—to give it a new treatment. According to Ward, the special PPE is as durable as ordinary clothing. “But, since the treated fabric soils less, the lab coats tend to last longer.” The clothing normally used in surgical settings in most hospitals is made of common cloth. Only in some types of procedures, such as childbirth or orthopedic surgery, where there is a lot of contact with blood, do medical staff receive waterproof lab coats. Some hospitals only provide disposable lab coats and no further protection.
Investment phase
The project will have two more phases. One will be to adapt the technology to different uses, including for visors, shoes and gloves, for example. “We will do laboratory tests to measure the degree of contamination of the clothing during routine use,” says Ward. So far this evaluation has only been carried out in vitro. The team also plans to subject the fabric to a challenge test that will expose it to large amounts of bacteria and fungi to see how it responds. “These two phases depend on a larger investment, which we do not yet have.”
Trabasso has a favorable assessment of the current project, but thinks that the conventional lab coats and jackets used today offer adequate protection. “What we are proposing is extra protection,” he says. “We need to prove that it is efficient and cost-effective. Water-repellent protection can be beneficial in terms of efficiency in certain situations, such as surgery or procedures with great exposure to blood.” The estimated cost per lab coat, for example, is between R$70 and R$80, according to Paul Formagio, of EPI Saúde. “This is R$5 more than an ordinary lab coat.”
Innovative entrepreneurship
Two other fabric manufacturing companies have incorporated nanotechnology into their production. One is TNS Nanotecnologia, located in the Centro Empresarial para Laboração de Tecnologias Avanzadas (Celta), a Certi Foundation incubator based in Florianópolis (Santa Catarina State). The company produces silver nanoparticles, in addition to other antimicrobial additives, which can be incorporated into fabrics, paints, plastics, as well as medical and ceramic equipment. The company was established in 2009 by a group of chemistry and engineering students of the Federal University of Santa Catarina (UFSC) and last year won the National Prize for Innovative Entrepreneurship in the Best Incubated Company category, awarded by the National Association of Enterprises Promoting Business Innovators (ANPROTEC). TNS has no products in stores, but rather sells nanoparticles to companies that incorporate the technology into their finished goods, such as textiles and footwear.
Managing Director Gabriel Nunes says the company sells its product to manufacturers of synthetic and cotton yarns, dye shops and textile companies. The main application for TNS nanoparticles in this market is in making socks, linings and insoles for shoes, towels, mattress covers, pillows, sheets, curtains, carpets and work clothes (lab coats and professional overalls). “One of the main advantages of the material impregnated with silver is that it inhibits the cross-contamination of microbial growth, which prevents the formation of mold and mildew, and combats the unpleasant odor of clothing and footwear caused by bacteria,” notes Nunes. “What this means is that people can wear the clothing for several hours or days (in the case of athletes) without this problem. The material can be laundered up to 50 times without losing its antimicrobial properties.”
In Joinville (also located in Santa Catarina State), the Diklatex Industrial Têxtil company produces meshes that contain nanoparticles of various materials for use in making sportswear. One of these materials is silicone, which gives fabrics greater durability and softness, and another material uses hydrophilisers, which absorb moisture from the body, such as sweat, and release it into the environment. Nanoencapsulated essences that perfume clothing are also used, in addition to silver. In the case of Diklatex, nanoparticles are imported from European companies.
According to a company press release, the sportswear segment has grown, and the company is also looking for pieces that can provide greater comfort during physical activities. The market for medical clothing that contains nanoparticles is also significant. Paulo Formagio, of EPI Saúde, estimates that the total number of health professionals, including aides, technicians and support staff, could reach 2.6 million, in addition to another 300,000 working in the field of veterinary medicine.
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