Antibacterial Efficiency of Stainless-Steel Grids Coated with Cu-Ag by Thermionic Vacuum Arc Method

Abstract

Autonomous smart natural ventilation systems (SVS) attached to the glass façade of living quarters and office buildings can help reducing the carbon footprint of city buildings in the future, especially during warm seasons and can represent an alternative to the conventional mechanical ventilation systems. The work performed in this manuscript focuses on the investigation of bacteria trapping and killing efficiency of stainless steel grids coated with a mixed layer of Cu-Ag. These grids are to be employed as decontamination filters for a smart natural ventilation prototype that we are currently building in our laboratory. The tested grids were coated with a mixed Cu-Ag layer using thermionic vacuum arc plasma processing technology. The fixed deposition geometry allowed the variation of Cu and Ag atomic concentration in coated layers as a function of substrate position in relation to plasma sources. The test conducted with air contaminated with a pathogen strain of staphylococcus aureus indicated that the filtering efficiency is influenced by two parameters: the pore size dimension and the coating layer composition. The results show that the highest filtering efficiency of 100% was obtained for fine pore (0.5 × 0.5 mm) grids coated with a mixed metallic layer composed of 65 at% Cu and 35 at% Ag. The second test performed only on reference grids and Cu-Ag (65–35 at%) under working conditions, confirm a similar filtering efficiency for the relevant microbiological markers. This particular sample was investigated from morphological, structural, and compositional point of view. The results show that the layer has a high surface roughness with good wear resistance and adhesion to the substrate. The depth profiles presented a uniform composition of Cu and Ag in the layer with small variations caused by changes in deposition rates during the coating process. Identification of the two metallic phases of the Cu and Ag in the layers evidences their crystalline nature. The calculated grain size of the nanocrystalline was in the range 14–21 nm.

Biocide effect against SARS-CoV-2 and ESKAPE pathogens of a noncytotoxic silver–copper nanofilm

“…Therefore, in this work, we propose using highly adhesive physical vapor-deposited AgCu nanofilms deposited on synthetic fabrics instead of impregnation or layer-by-layer methods with polymer composites containing NPs [61,62]. The antibacterial activity of Ag-Cu films deposited on polymeric or metallic materials has been previously demonstrated [63][64][65][66][67][68][69], where the advantage of using bimetallic particles instead of single materials is related to the enhanced charge transfer mechanism when alloys are used [23,[70][71][72]. Moreover, Ag-Cu nanoalloys have demonstrated enhanced resistance to electromigration and oxidation [73], high stability, and improved bactericidal effects compared to pure Ag [74].…”

Antimicrobial activity of silver-copper coating against aerosols containing surrogate respiratory viruses and bacteria

“…For instance, some studies have evaluated Cu-Ag coatings solely against S. aureus [ 27 , 31 ], while in another work, a membrane loaded with AgCu-NPs on PP was tested against two bacteria, namely E. coli and S. aureus [ 64 ]. In contrast, our study aimed to assess the antibacterial activity of the AgCu nanolayer against a total of twelve Gram-positive and Gram-negative respiratory and oral nosocomial bacteria.…”

“…Ag-NPs PVD-coated Ag-NPs TGEV-Coronavirus SARS-CoV-2 Antiviral properties on TGEV infection Highly potent microbicides [23,24] Monkeypox Antiviral effect [25] RSV-Virus 44% Inhibition of viral activity [26] Gram-positive Antibacterial activity [27] Gram-negative bacteria Cu surfaces Cu-Ag coating Human Norovirus Virus degradation in less than 5 min [28] Virus loses its capsid integration [29] SARS-CoV-2 Virus inhibition at � 4 h [30] Staphylococcus aureus Filtration efficiency attributed by the composition of the Cu-Ag (65-35%) [31] CuS coating SARS-CoV-2…”

Sputter-Deposited Cr–Ag Films for Environmental Antimicrobial Applications

“…It is of crucial importance to impede the spread of unwanted bacteria and viruses in clinical and environmental circumstances. Over 20 metallic elements have been studied for antimicrobial property [5,6], in which Ag, Cu, Zn, etc are demonstrated to possess good microcidal activity [1,[6][7][8][9]. In particular, silver as a historic and effective antimicrobial agent has a wide spectrum against many drug-resistant bacteria [10] and a fairly good compatibility with mammalian cells.…”