Biocidal Silver and Silver/Titania Composite Films Grown by Chemical Vapour Deposition

Abstract

This paper describes the growth and testing of highly active biocidal films based on photocatalytically active films ofTiO2, grown by thermal CVD, functionally and structurally modified by deposition of nanostructured silver via a novel flame assisted combination CVD process. The resulting composite films are shown to be highly durable, highly photocatalytically active and are also shown to possess strong antibacterial behaviour. The deposition control, arising from the described approach, offers the potential to control the film nanostructure, which is proposed to be crucial in determining the photo and bioactivity of the combined film structure, and the transparency of the composite films. Furthermore, we show that the resultant films are active to a range of organisms, including Gram-negative and Gram-positive bacteria, and viruses. The very high-biocidal activity is above that expected from the concentrations of silver present, and this is discussed in terms of nanostructure of the titania/silver surface. These properties are especially significant when combined with the well-known durability of CVD deposited thin films, offering new opportunities for enhanced application in areas where biocidal surface functionality is sought.

Nanostructured silver vanadate as a promising antibacterial additive to water-based paints

“…Thus, DNA backbone containing phosphorus and the cell membrane proteins containing sulfur are the preferred sites for the binding of AgNPs. 18,21,28,30 Thus, when the DNA comes into contact with Ag ions, it loses its replication capacity. 31,32 Beyond this damage, we observed an increase of permeability on the membrane caused by Ag-based compounds and that thereafter affected the transport property.…”

Silver nanocluster-silica composite antibacterial coatings for materials to be used in mobile telephones

“…Various antibacterial coatings have been investigated in the literature [1][2][3][4][5][6][7][8][9][10][11] and some of them are available on the market [12][13][14][15]. In particular silver-containing materials are being widely used since silver is known to have a powerful anti-bacterial activity [5,16,17] and to induce low bacterial resistance compared to that of antibiotics.…”

“…Several techniques able to provide an antibacterial surface on different materials have been developed [1][2][3][4][5][6][7][8][9][10][11].…”

Photocatalytic Semiconductors

“…Among the different doped materials reported, silver, vanadium, iron, and palladium-modified nitrogen-doped TiO 2 have been tested to enhance photocatalytic performance of titania for gram-negative bacteria such as Escherichia coli, Pseudomonas aeruginosa, and Prevotella intermedia inactivation in water Wu et al 2008;Sun et al 2010;Ubonchonlakate et al 2012;Nair et al 2012) as well as some gram-positive bacteria, i.e., MRSA, Staphylococcus epidermidis, S. saprophyticus, S. pyogenes, Streptococcus aureus, and Saccharomyces cerevisiae (Mo et al 2007;Sheel et al 2008;Lu et al 2006;Erkan et al 2006), and a few protozoa such as Tetraselmis suecica, Amphidinium carterae, and Chlorella vulgaris (Rodríguez-González et al 2010;Foster et al 2011). …”