According to Light Metal Age, Canadian A3 Surfaces has developed a patented technology to produce antibacterial anodized aluminum products, which can inhibit the spread of bacteria or viruses on the surface. Currently, Rio Tinto is providing funding and back-up support for the entire test phase of antimicrobial aluminum technology, with a view to early commercial production and application.
Nosocomial infections (called nosocomial infections) are a common problem. In Canada, this type of infection causes approximately 8,000 to 12,000 deaths each year. In the United States, the death toll is approximately 80,000. A3 Surfaces, located in Saguenay, Quebec, Canada, is a start-up company dedicated to developing high-contact self-disinfection devices and surface products by eliminating cross-contamination in medical institutions. Recently, A3 Surfaces has developed a breakthrough surface treatment technology that can convert aluminum products into antibacterial surfaces, thereby significantly reducing the risk of bacterial and viral disease transmission (Figure 1). The technology can push cross-contamination from a few seconds to a few minutes, which means it can break down more stubborn microorganisms, which generally require more time to eliminate. A3 Surfaces said that this technology can be used in hospitals, but also in public transportation, large building air intake HVAC, classrooms, food processing and other fields, more likely to prevent a new round of influenza pandemic.
Figure 1 A3 Surfaces has developed an antibacterial treatment for aluminum, which can significantly reduce the spread of bacterial or viral infections on surfaces such as door handles
The study of this technology began with the end of a course on aluminum conversion training at Chicoutimi College, when Maxime Dumont and Jocelyn Lambert had the idea of creating antibacterial aluminum. During their research, they found that the application of existing biocide products on anodized aluminum has antibacterial and bacteriostatic effects. In 2013, they declared a patented technology for this concept.
A3 Surfaces. was founded in 2015 and is located in Quebec, Canada. It was formed by Martin Lambert and co-inventors Maxime Dumont and Jocelyn Lambert to further develop the potential of antibacterial aluminum. During the creation of A3 Surfaces, it received financial and logistical support from the Rio Tinto Regional Economic Development Team. Rio Tinto immediately saw the huge potential of this technology. Over the past five years, Rio Tinto has invested a total of $250,000 in start-up support in the A3 Surfaces Division, promoting contact with potential customers and helping A3 Surfaces coordinate with government regulatory agencies at all levels.
Over time, A3 Surfaces has refined its biocide formulation to make it more effective, and prepared a self-sterilizing anodized aluminum. This technology, called UmanProtek, allows self-disinfection of aluminum parts that have undergone such surface treatment. In December 2019, the company filed its second patent application requesting protection of the technology worldwide.
Currently, A3 Surfaces operates in 1100 square feet of leased space (Figure 2), and there are 13 production units (3 feet long x 1 foot wide x 2 feet deep) in the production workshop. The existing equipment is used for research and development work, and at the same time, the existing contract of anodizing antibacterial parts can be completed. Among them, the processing of large aluminum parts was subcontracted to an external company to complete. The company has an anodizing tank of 8 feet x 3 feet x 4 feet. Currently, the company is building a 15-foot long slot production unit. Part of the business model of A3 Surfaces is carried out through commercial licensing, because the anodizing market is directly linked to the end user.
Figure 2 A3 Surfaces production demonstration line (the person standing next to is A3 Surfaces President Martin Lambert)
UmanProtek is an advanced processing technology that combines the anodizing process of aluminum with biochemistry. Essentially, the chemical release process of biocides that makes this technology possible is governed by the physical chemistry van der Waals force and Fick's law of diffusion. Van der Waals force is a weak force that is active in the nano-environment and can keep biocides in the pores. Fick's law controls the diffusion of biocides on the surface of oxidized aluminum substrates.
Choosing the correct, non-toxic and self-disinfecting fungicide is an important part of developing human protection technology. Biocides must meet several considerations, such as molecular size, diffusion rate, and chemical stability. In addition, if the fungicide significantly affects the biota (friendly natural flora on people's skin), it will have a harmful resistance to microorganisms. In addition, this agent needs to be non-toxic and not resistant to antibiotics.
Jean-Luc Bernier, vice president of technology at A3 Surfaces, said: "We tested a large number of biocides and found that quaternary ammonium compounds (QAC) and silver are the best to inactivate Gram-positive bacteria, Gram-negative bacteria and viruses. Combination. Silver can play a preventive role because it is not toxic enough to kill microorganisms, but it is strong enough to avoid the reproduction of microorganisms. In medical institutions, QAC and silver have been used for many years and have been approved by health authorities."
The UmanProtek process is carried out in four stages: surface treatment, anodizing, impregnation and sealing of antibacterial substances. The surface treatment stage includes cleaning and peeling the substrate to obtain a uniform surface with minimal defects.
Anodizing types II and III are the crucial second step in this process because they form the honeycomb structure of the alumina nanoreservoir and control its pore size. Hard anodizing (Rockwell hardness about 50) must be monitored according to military (MIL) specifications. Most problems occur due to the inability to guarantee quality. For example, if the anodizer does not use deionized water during the cleaning step, the hardness of the water will cause spots, resulting in an unacceptable visual appearance.
Because some alloy elements, such as silicon and iron, are not conducive to obtaining a uniform finish, not all aluminum grades are suitable for obtaining nanopores with appropriate size and aspect ratio. Therefore, 1000, 3000, 5000 and 6000 series alloys are preferred, and processed through decorative and architectural finishes to prepare uniform nanoporous products.
The third stage is to impregnate the nanopores on the aluminum surface with antibacterial substances. Among antibacterial wipes sold in grocery stores, QAC is a versatile antibacterial substance. In this step, the concentration and contamination of the biocide must be monitored.
Closure is the final stage of nanopore closure. Using patented technology to monitor the sealing process.
It has been proven that UmanProtek can significantly reduce the risk of spreading microbial infections through cross-contamination, enabling aluminum components to disinfect themselves. Research conducted by Dr. Nathalie Faucheux and Dr. Louis Charles Fortier of Sherbrooke University found that products treated with A3 Surfaces can kill 99.9% of bacteria (Staphylococcus aureus, which is a skin infection and respiratory tract infection in 5 minutes or less) And common pathogens of food poisoning) (Figure 3). In addition, Professor Nathalie Tufenkji of McGill University conducted a test, and the results showed that the contact with materials of A3 Surfaces technology can reduce the bacterial load (staphylococcus aureus) on the contaminated hands by 80% within 5 seconds.
Figure 3 Test with a photometer to check the removal of bacteria on the treated aluminum surface. Hundreds of colony forming units can be seen on the untreated surface (A), but not detected on the antibacterially treated surface (b).
The research also shows that the antibacterial aluminum obtained by hard anodizing and QAC treatment has a long service life and long-term stability. For example, a sample prepared in a laboratory 10 years ago still shows the effectiveness of antibacterial effects.
In addition, the Canadian National Research Council (NRC) Aluminum Technology Center (ATC) uses standard hospital cleaners to measure product wear. In the test, ATC used the Gardner abrasion tester and conducted 200 back and forth tests on the surface treated by UmanProtek with a household sponge. There are 3 types of test products: bleach (0.5% active chlorine), Vert-to-Go disinfection Liquid (1 ml of water is 7 ml) and stainless steel cleaner (undiluted). The results show that the surface of the tested aluminum product retains its antibacterial properties.
In addition, A3S installed a sliding door panel in a public library where 4,000 people use the sliding door panel every week. After 30 months, it was found that the product's biological antibacterial properties were comparable to the initial ones. Based on these tests, A3 Surfaces estimates the life expectancy of antibacterial-treated aluminum products to be 20 years.
Currently, the number of UmanProtek products from A3 Surfaces is limited. The product can be sold in the United States, and the scope of exemption includes aluminum products treated with EPA/FDA approved biocides. For sales in Canada, the company is awaiting approval from Health Canada and the project is progressing smoothly.
Large-area surface materials (such as walls or tabletops) must be made of aluminum extruded plates. Compared with continuous thin-plate roll anodizing, the use of extruded plates is not economical. A3 Surfaces is negotiating with coil anodizing manufacturers to expand a wider range of applications.
A3 Surfaces is working with Chicoutimi University Hospital and the Quebec government to further prove the effectiveness of the technology in the hospital environment (Figure 4). The validity test is carried out as follows: using 2 rooms monitored by an independent laboratory, one room is a standard hospital room equipped with typical user equipment; the other room is remodeled and uses A3 Surfaces’ biocidal aluminum components ( Including door handles, walls, trays, etc.) for renovation. Sampling the above 2 rooms every week and comparing the results and testing the surface at the same time to prove the reduction of cross-contamination. During this period, due to some reasons (partly related to the outbreak of the new crown epidemic), the experiment was temporarily suspended. However, the current epidemic has slowed down and the comparative experiment will continue.
Figure 4 The technology is being tested in a hospital to verify its antibacterial ability
Rio Tinto will continue to provide funding and back-up support throughout the test phase of antimicrobial aluminum technology. In 2020, Rio Tinto will focus on helping A3 Surfaces develop its business models and plans, while simultaneously developing the market. Emmanuel Bergeron, Director of the Regional Economic Development Quebec in Quebec, said: "The innovations of A3 Surfaces in Quebec may become the main means of fighting epidemics and infections. In daily life, this technology is widely used, we It’s great to see the increasing interest in antibacterial aluminum in society."
(Part of the company's antibacterial aluminum products)