Highly bactericidal Ag nanoparticle films obtained by cluster beam deposition

Abstract

The use of silver nanoparticle in health care is getting more widespread. The authors here describe the technique of cluster beam deposition for spraying silver on surfaces used in health care sectors. This may open a new avenue for future anti-bacterial coatings.

Direct synthesis of antimicrobial coatings based on tailored bi-elemental nanoparticles

“…Overall, the microbicidal activity of AgTi5050 NP films was found to be similar to that of pure Ag NP films synthetized by the same methodology. 24 Indeed, although a direct comparison was not possible due to different substrate types and revised microbiological procedures, a similar reduction in the number of viable bacterial cells was observed with strains tested in both studies, using comparable bacterial inocula for surface contamination. These results encourage further studies to exploit SCBD's ability to produce multielemental NPs to include other antimicrobial metals in the NPs coating (possibly broadening the antimicrobial spectrum toward Gram-positive bacteria).…”

“…The NPs are similar to the Janus type NPs, 20 with metallic Ag nano-crystals partly embedded in an amorphous TiO 2 matrix. The nano-structured Ag-Ti coating shows good adhesion to the substrate and exhibits an exceptional bactericidal effect against major Gram-negative nosocomial pathogens, remarkably similar to a pure Ag NPs coating, 24 but with an 85% lower Ag mass content. Thus, this work opens the possibility to produce radically new materials for a variety of applications, engineering the coating properties with a potentially unlimited set of elements: broadening the antimicrobial spectrum for healthcare environments by introducing other microbicidal metals or tailor the coating adhesion by varying the elements relative concentration in the NPs.…”

“…Moreover, our data clearly indicate that the compositional changes in the pristine rod (i.e., pure Ag, AgTi8020, AgTi5050) correspond to an analogous variation in the produced bi-NPs stoichiometry, proving that SCBD is a powerful tool to tailor the NPs chemical composition simply adjusting the Ag/Ti relative concentration in the initial rod. It is also worth noting that this method has already been used to deposit Np coatings on glass, 24 sapphire, 7 semiconductors, 23 and on PVA electrospun fibers, 32 and can be extended to any metal surface, even textiles and paper, provided they can be inserted into vacuum. Such flexibility can open a wide range of applications of such coatings, from sensors to paper electronics.…”

“…Such flexibility can open a wide range of applications of such coatings, from sensors to paper electronics. The antimicrobial features of the bi-elemental coatings were characterized for the AgTi5050 NPs system, the one with lower Ag amount with respect to a similar coating of ultrapure Ag NPs obtained by SCBD, 24 to reduce the precious metal content in potential applications. The AgTi5050 coatings (thickness of one NPs layer) were found to be extremely effective against all the Gramnegative strains tested (i.e., two reference strains of Escherichia coli and Pseudomonas aeruginosa, and two multidrug resistant clinical isolates of P. aeruginosa, and Acinetobacter baumannii (Table S5 of the supplementary material), being able to almost completely sterilize a high bacterial inoculum, ∼1 × 10 7 colony forming units (CFU), in 3 h (Figure 3(a)).…”

Antimicrobial silver-filled silica nanorattles with low immunotoxicity in dendritic cells

“…With the emergence of bacterial resistance to conventional antibiotics, silver-based compounds and silver nanoparticles again enjoy rising popularity [5][6][7][8][9][10][11][12] as antimicrobial and healing agents. 13,14 Undoubtedly, the greatest advantage of silver originates from its multidirectional mode of action against microbes.…”