A Compatible and Efficient Fabrication of Bi-Continuous Nanoporous Copper Films

To cater to the application in various micro/nano devices, this paper reports a compatible and efficient approach combining electrodeposition and dealloying to fabricate bi-continuous nanoporous copper films. In the electrodeposition step, effect of concentration ratio of different ions, pH of the solution and cathode current density on the elementary composition and microscopic morphology of the deposited alloy are systematically investigated, obtaining an optimum condition with good stability and process compatibility. A uniform copper-zinc alloy with its zinc content improved to ~67 at.% is prepared under this condition. A uniform nanoporous copper with an average pore size of 150 nm is fabricated by ultrasonic assisted dealloying whose efficiency is significantly improved compared to free dealloying. This method is promising to be used in the mass production of nanoporous copper films, benefiting researches on various practical applications in micro/nano devices.

Hygienic assessment of population health risk under exposure to chemicals that penetrate drinking water from household water mixers

At present a truly vital task is to evaluate possible changes in the structure and properties of drinking water occurring in the process of delivering it to end customers. Our research aim was to perform hygienic assessment of health risks caused by consumption of drinking water with changed chemical structure influenced by domestic faucets made from zinc alloys. Hygienic assessment of drinking water was performed to test its conformity with the requirements fixed in the Sanitary Rules and Standards SanPiN 1.2.3685-21 “Hygienic standards and requirements to providing safety and (or) harmlessness of environmental factors for people”. Water samples were aged in new household water mixers with their cases made from ZAM zinc alloy (a zinc alloy doped with aluminum, magnesium, and copper) at pH6 and pH9 in accordance with the State Standard GOST 34771-2021 “Sanitary-technical water mixing and distributing accessories. Testing procedures”. Health risks for children and adults and population risks were assessed for situations involving oral and cutaneous introduction according to the Guide R 2.1.10.1920-04 Human Health Risk Assessment from Environmental Chemicals. We established that water samples aged in household water mixers contained authentically elevated concentrations of metals included into ZAM alloy, namely copper, nickel, lead, and zinc, both at pH = 6 and pH = 9. We also detected enhanced organoleptic properties: color grew by 2–2.3 times and turbidity by 2.3–5 times. Carcinogenic risks caused by consuming water with changed properties turned out to be unacceptable both for children and adults. We also established that calculated hazard index for the blood system didn’t conform to hygienic requirements; calculated hazard indices for the central nervous system, liver, hormonal and reproductive systems were statistically significantly higher when people consumed drinking water with changed properties. We also calculated population carcinogenic risks for the whole population in the Russian Federation based on the maximum possible exposure to drinking water with changes in its chemical properties due to household water mixers. The total population risks amounted to approximately 131 thousand cases. Our research indicates it is necessary to develop preven-tion activities with a carefully planned monitoring system and control over quality and use of domestic faucets.

Virus matrix interference on assessment of virucidal activity of high-touch surfaces designed to prevent hospital-acquired infections

Objectives/purpose High-touch surfaces are a critical reservoir in the spread of nosocomial infections. Although disinfection and infection control protocols are well developed, they lack the ability to passively reduce the pathogenic load of high-touch surfaces. Copper and its alloys have been suggested as a surface that exhibit continuous biocidal effects. Antimicrobial studies on these surfaces are prevalent, while virucidal studies are not as well explored. The goal of this study was to first determine the virucidal activity of a copper–nickel–zinc alloy and to then examine the effect of soiling and virus preparation on virucidal activity. Methods A baculovirus vector was used as an easily quantifiable model of an infectious enveloped animal cell virus. Droplets containing virus were deposited on surfaces and allowed to stay wet using humidity control or were dried onto the surface. Virus was then recovered from the surface and assayed for infectivity. To examine how the composition of the droplet affected the survival of the virus, 3 different soiling conditions were tested. The first two were recommended by the United States Environmental Protection Agency and the third consisted of cell debris resulting from virus amplification. Results A copper–nickel–zinc alloy was shown to have strong virucidal effects for an enveloped virus. Copper, nickel, and zinc ions were all shown to leach from the alloy surface and are the likely cause of virucidal activity by this surface. Virucidal activity was achieved under moderate soiling but lost under high soiling generated by routine virus amplification procedures. The surface was able to repeatably inactivate dried virus droplets under moderate soiling conditions, but unable to do so for virus droplets kept wet using high humidity. Conclusion Ion leaching was associated with virucidal activity in both wet and dried virus conditions. Soiling protected the virus by quenching metal ions, and not by inhibiting leaching. The composition of the solution containing virus plays a critical role in evaluating the virucidal activity of surfaces and surface coatings.