Nov_Dec_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | N O V E M B E R / D E C E M B E R 2 0 2 0 4 0 iTSSe TSS iTSSe TSS C oronavirus disease 2019 (COVID-19) is already the third coronavirus outbreak in the past two decades. SARS- CoV-2, the strain of coronavirus that causes COVID-19, may continue to spread worldwide for years and outbreaks of new coronaviruses are very likely in the future. Solutions that could help to reduce the spread of such viruses to curb this pandemic or future epidemics are attracting increas- ing attention. Human coronaviruses, including SARS-CoV-2, are mainly transmitted through respiratory droplets of an infected per- son. One possible route of contracting the virus is after touch- ing a contaminated surface (fomites) and then the eyes, nose, or mouth [1] . The possibility of fomite transmission is reduced through cleaning and disinfecting, however there is a practical limit to the effectiveness of this strategy based on its frequen- cy. Using materials that continuously inactivate viruses on high-touchmetallic surfaces (e.g., door handles, stair rails, grab bars) of public spaces (e.g., healthcare facilities, mass transit, commercial buildings, schools) may provide an additional control measure. There is already a large body of evidence showing that copper and a range of copper alloys (Cu/Cu al- loys) exhibit intrinsic broad-spectrum antimicrobial activities, killing several types of bacteria and inactivating enveloped and non-enveloped RNA viruses by 99.9% in as little as a few minutes to a few hours [2-4] . In the latest study, live SARS-CoV-2 could not be detected on copper surfaces after 4 hours while it was still viable after 72 hours on stainless steel [5] , the most commonly used high-touchmetallic surfacematerial. Both the U.S. Environmental Protection Agency (EPA) and Health Can- ada recognize a range of antimicrobial Cu/Cu alloys as safe- to-use materials to manufacture products with antimicrobial properties [6,7] . Although copper-based antimicrobial products are already commercialized, their deployment has been very limited as extensive replacement of many high-touch com- ponents by solid structural copper is cost prohibitive and, in some cases, impractical. The current pandemic, however, has prompted a re-examination of the possibility to broadly use such additional passive preventionmeasures that have proved to be efficient in limiting the spread of infectious diseases. One economically viable and more practical approach to the use of solid antimicrobial Cu/Cu alloys is to use coatings. The idea is to use cold spray, which is a production-ready, solid-state process to apply metal coatings with high throughput, in am- bient air and at room temperature, in robotic settings [8] . Metal powders are sprayed at high velocity onto a surface, where they adhere upon impact without oxidation [8] . The resulting coatings are fully dense and can be easilymachined to provide a smooth surface desirable for this application. Because of its scalability to high volumes and its ability to coat complex ge- ometries, cold spray is a promising coating process for this ap- plication. Moreover, copper coatings deposited by cold spray have been shown to exhibit excellent antimicrobial effective- ness [9] . It has been hypothesized that the high strain hardening that occurs in cold spray results in the creation of deformation defects, such as high dislocation density and grain refinement, potentially yielding higher kinetic rate of copper ion release, FEATURE 4 *Member of ASM International MATERIALS SCIENCE AND CORONAVIRUS SERIES DEVELOPMENT AND VALIDATION OF HIGH-PERFORMANCE SARS-CoV-2 ANTIVIRAL COATINGS FOR HIGH-TOUCH SURFACES A joint Canadian project aims to curb the COVID-19 pandemic and future epidemics with cold sprayed, copper-based coatings. Eric Irissou,* Bruno Guerreiro, and Maniya Aghasibeig, National Research Council Canada, Boucherville, QC, Canada Chen Liang and Saina Beitari, Lady Davis Institute for Medical Research at the Jewish General Hospital, Department of Medicine, Montreal, McGill University, QC, Canada Stephen Yue, FASM* and Hanqing Che,* Department of Mining and Materials Engineering, McGill University, Montreal, QC, Canada Amir Nobari, 5N Plus Inc., Montreal, QC, Canada Luc Pouliot,* Fernanda Caio,* and Sylvain Desaulniers,* Polycontrols Technologies Inc., Brossard, QC, Canada Murray Pearson, Kevin Seow, and Jean-François Boulet, Hatch Ltd., Mississauga, ON, Canada