The influence of nanoscopically thin silver films on bacterial viability and attachment

Abstract

The physicochemical and bactericidal properties of thin silver films have been analysed. Silver films of 3 and 150 nm thicknesses were fabricated using a magnetron sputtering thin-film deposition system. X-ray photoelectron and energy dispersive X-ray spectroscopy and atomic force microscopy analyses confirmed that the resulting surfaces were homogeneous, and that silver was the most abundant element present on both surfaces, being 45 and 53 at.% on the 3- and 150-nm films, respectively. Inductively coupled plasma time of flight mass spectroscopy (ICP-TOF-MS) was used to measure the concentration of silver ions released from these films. Concentrations of 0.9 and 5.2 ppb were detected for the 3- and 150-nm films, respectively. The surface wettability of the films remained nearly identical for both film thicknesses, displaying a static water contact angle of 95°, while the surface free energy of the 150-nm film was found to be slightly greater than that of the 3-nm film, being 28.8 and 23.9 mN m(-1), respectively. The two silver film thicknesses exhibited statistically significant differences in surface topographic profiles on the nanoscopic scale, with R (a), R (q) and R (max) values of 1.4, 1.8 and 15.4 nm for the 3-nm film and 0.8, 1.2 and 10.7 nm for the 150-nm film over a 5 × 5 μm scanning area. Confocal scanning laser microscopy and scanning electron microscopy revealed that the bactericidal activity of the 3-nm silver film was not significant, whereas the nanoscopically smoother 150-nm silver film exhibited appreciable bactericidal activity towards Pseudomonas aeruginosa ATCC 9027 cells and Staphylococcus aureus CIP 65.8 cells, obtaining up to 75% and 27% sterilisation effect, respectively.

Efficient surface modification of biomaterial to prevent biofilm formation and the attachment of microorganisms

“…Heterogeneously distributed throughout the TiN matrix, the presence of the silver resulted in changes in the surface nanotopographies -surface features, grain sizes, and physicochemistry -with most profound changes observed at a silver concentration of 16.7 at.% (Whitehead et al 2010). Recently, Ivanova et al (2011) used magnetron sputtered nanoscopically thin silver films to show that while silver ion concentration may be the major determinant of bacterial viability, the extent of bacterial attachment and the patterns are largely affected by surface topography of the films . A strong correlation was also detected between total surface energy γ TOT of the silver coating and P. aeruginosa adhesion, with the number of adhered bacteria increasing linearly with γ TOT but decreasing linearly with an increasing electron donor component γ− (Shao and Zhao 2010a).…”

Synthesis and characterization of an injectable and self-curing poly(methyl methacrylate) cement functionalized with a biomimetic chitosan–poly(vinyl alcohol)/nano-sized hydroxyapatite/silver hydrogel

“…The results of disk-diffusion test against E. coli and S. aureus was demonstrated by the presence of an inhibition zone (Fig. 46,47 So besides ZOI, contact bacteriostatic and the sustained-release bacteriostatic of different cements against E. coli and S. aureus were also evaluated to fully reveal the anti-bacterial abilities of cements. The comparisons of ZOI presented that all CS based hydrogel exhibited antibacterial activities but Ag + enriched cements revealed clearer and greater translucent inhibition zones.…”

Emerging Trends in Abdominal Wall Reinforcement: Bringing Bio‐Functionality to Meshes

“…Indeed, antibacterial metal ions have been known for centuries as protective agents against the surface colonization by bacteria. They have the advantage of being effective against both gram‐positive and gram‐negative bacteria, adding to the fact that they have a relatively low risk of inducing resistance . In this context, silver gold and palladium have been added to meshes by sputter coating (also called physical vapor deposition) or by plasma polymerization followed by nanoparticle agglomeration .…”