Antimicrobial properties of a multi-component alloy

Abstract

High traffic touch surfaces such as doorknobs, countertops, and handrails can be transmission points for the spread of pathogens, emphasizing the need to develop materials that actively self-sanitize. Metals are frequently used for these surfaces due to their durability, but many metals also possess antimicrobial properties which function through a variety of mechanisms. This work investigates metallic alloys comprised of several metals which individually possess antimicrobial properties, with the target of achieving broad-spectrum, rapid sanitation through synergistic activity. An entropy-motivated stabilization paradigm is proposed to prepare scalable alloys of copper, silver, nickel and cobalt. Using combinatorial sputtering, thin-film alloys were prepared on 100 mm wafers with ≈50% compositional grading of each element across the wafer. The films were then annealed and investigated for alloy stability. Antimicrobial activity testing was performed on both the as-grown alloys and the annealed films using four microorganisms—Phi6, MS2, Bacillus subtilis and Escherichia coli—as surrogates for human viral and bacterial pathogens. Testing showed that after 30 s of contact with some of the test alloys, Phi6, an enveloped, single-stranded RNA bacteriophage that serves as a SARS-CoV-2 surrogate, was reduced up to 6.9 orders of magnitude (> 99.9999%). Additionally, the non-enveloped, double-stranded DNA bacteriophage MS2, and the Gram-negative E. coli and Gram-positive B. subtilis bacterial strains showed a 5.0, 6.4, and 5.7 log reduction in activity after 30, 20 and 10 min, respectively. Antimicrobial activity in the alloy samples showed a strong dependence on the composition, with the log reduction scaling directly with the Cu content. Concentration of Cu by phase separation after annealing improved activity in some of the samples. The results motivate a variety of themes which can be leveraged to design ideal antimicrobial surfaces.

Enhanced Bacterial Growth by Polyelemental Glycerolate Particles

“…14 Alamdari et al 9 reported the substantial 98.5% antibacterial efficacy of the TiZrTaNbWAg polyelemental film against Escherichia coli (E. coli) bacteria. Murray et al 10 reported the 6.4 log reduction of the double-stranded deoxyribonucleic acid (DNA) activity of E. coli bacteria after interacting with the CoCuAgNiSi polyelemental film. Chen et al 15 evaluated 97.45% antibacterial efficacy of the CrFeNiCuSi polyelemental alloy against E. coli bacteria by exhibiting synergistic activity of multiple metal cations.…”

“…Polyelemental materials − are an emerging class of materials with vast compositional space that can be tuned to promote the synergistic properties of alloyed materials for various applications ranging from clean energy , to healthcare , and structural materials. , Recent studies show the potential of polyelemental materials for biological applications such as antibacterial agents − or medical implants. , Polyelemental alloys possess excellent mechanical and chemical stability attributing to their configurational mixing entropy . Alamdari et al reported the substantial 98.5% antibacterial efficacy of the TiZrTaNbWAg polyelemental film against Escherichia coli (E.…”

“…coli) bacteria. Murray et al reported the 6.4 log reduction of the double-stranded deoxyribonucleic acid (DNA) activity of E. coli bacteria after interacting with the CoCuAgNiSi polyelemental film.…”