Antibacterial activity of thin films TiO2 doped with Ag and Cu on Gracilicutes and Firmicutes bacteria

Abstract

This article aims to explore the antibacterial activity of thin films of TiO doped with Ag and Cu using two types of Gram-negative and Gram-positive test bacteria with clinical significance (Gracilicutes and Firmcutes bacteria). The thin films (thickness of about 60 nm) were deposited on glass substrates by radio frequency magnetron co-sputtering (r.f. power of 50 W) of TiO target with Ag and Cu pieces on its surface in an Ar atmosphere (0.8 Pa) without heating during the deposition. The total surface area of the Ag was 60 mm and that of the Cu was 100 mm . Bacillus cereus, Staphylococcus epidermidis, Salmonella enterica, Escherichia coli and Pseudomonas sp. were used as test strains. The antibacterial actvity of the films was evaluated by the classical Koch's method and optical density measurements. The bactericidal effect was established at different time points between 30 min and 90 min for Pseudomonas sp. and S. enterica. The Firmicutes bacteria B. cereus and S. epidermidis were killed at the 4 and 8 hour of the treatment, respectively. The effect on E. coli was bacteriostatic until the 10 hour. The results were confirmed by assessment of the bacterial dehydrogenase activity. The studied thin films of TiO co-doped with Ag and Cu have a potential for application as antibacterial coatings.

Antibacterial effect of TiO2:Cu:Ag thin coatings on Pseudomonas strain measured by microbiological and ATP assays

“…The combination of copper and silver nanoparticles leads to a stronger antibacterial effect at a lower concentration of eluted ions . The strongly granulated surface of TiO 2 :Cu:Ag presented on the SEM images can be perceived as a more effective model for an antimicrobial agent . This confirms the fact that the antimicrobial effect of nanomaterials is complex and is a combination of composition, structure, size, and ratio of nanoparticles.…”

“…This confirms the fact that the antimicrobial effect of nanomaterials is complex and is a combination of composition, structure, size, and ratio of nanoparticles. It could be expressed from a slowing of growth rate to complete bacterial inactivation achieved by more than one mechanism, regardless of the structure of the bacterial cell wall [15,16,19,[25][26][27].…”

“…The results of SEM micrographs proved the membrane demolition after contact with the thin nanocomposite film and leakage of the cells content (Figure 4) [17][18][19]. The bacteriostatic effect and adaptation of Pseudomonas DSM50026 to the tested annealed nanomaterials could be explained by the ability of this bacterial species to activate special transport pumps for an export of the nanoparticles or ions out of the cell.…”

Silver nanoparticle effect on Salmonella enterica isolated from Northern West Egypt food, poultry, and calves

“…The success of Ag-NPs as effective antimicrobial is strongly strain dependent, since sensitivity to action of Ag-NPs, and MIC, thus is probably due to cell wall thickness differences. Berton et al (2014), He et al (2016), andStoyanova et al (2016) said that thus due to sensitivity, while Silver et al (2006) is probably genetic factors specifically intrinsic of each strain including the presence of specific determinant of resistance, the possible mechanism of action is that the metal nanoparticles are carrying the positive charge and microbes the negative charges which create the electromagnetic attraction and microbe get oxidized (Rezaei Zarchi et al, 2010) or nanoparticles which react with thiol group (-SH) of the protein present in the cell surface of bacteria leads to lysis (Zhang 2013).…”

Synthesis and characterization of magnesium doped titania for photocatalytic degradation of methyl red

“…Titanium dioxide doped with transition metals like Fe and Co has also been prepared by the previous scientists by sol-gel method [1,14]. STOYANOVA et al developed iron and copper doped titania nanoparticles for their potential use as antibacterial agents [15]. CHEKURI and co-workers synthesized various concentrations of cobalt doped titania nanopowders following a surfactant free approach and found them reasonably photocatalytically active for the degradation of azo dye Acid Red as well as an exceptional antibacterial agent against Escherichia coli [16].…”