Potential of silver nanoparticle‐coated polyurethane foam as an antibacterial water filter

Abstract

Silver nanoparticles can be coated on common polyurethane (PU) foams by overnight exposure of the foams to nanoparticle solutions. Repeated washing and air-drying yields uniformly coated PU foam, which can be used as a drinking water filter where bacterial contamination of the surface water is a health risk. Nanoparticles are stable on the foam and are not washed away by water. Morphology of the foam was retained after coating. The nanoparticle binding is due to its interaction with the nitrogen atom of the PU. Online tests were conducted with a prototypical water filter. At a flow rate of 0.5 L/min, in which contact time was of the order of a second, the output count of Escherichia coli was nil when the input water had a bacterial load of 10 5 colony-forming units (CFU) per mL. Combined with the low cost and effectiveness in its applications, the technology may have large implications to developing countries. B 2005 Wiley Periodicals, Inc.

Strain specificity in antimicrobial activity of silver and copper nanoparticles

“…The antimicrobial properties of silver nanoparticles are well-established [12][13][14][15] and several mechanisms for their bactericidal effects have been proposed. Although only a few studies have reported the antibacterial properties of copper nanoparticles, they show copper nanoparticles have a significant promise as bactericidal agent [16].…”

“…Yoon et al [19] reported the antibacterial effects of silver and copper nanoparticles using single representative strains of E. coli and Bacillus subtilis, where the copper nanoparticles demonstrated superior antibacterial activity compared to the silver nanoparticles. Silver and copper nanoparticles supported on various suitable materials, such as carbon, polyurethane foam, polymers and sepiolite have also been effectively used for bactericidal applications [13,14,[20][21][22]. While various hypotheses have been proposed to explain the mechanism of antimicrobial activity of silver nanoparticles, it is widely believed that silver nanoparticles are incorporated in the cell membrane, which causes leakage of intracellular substances and eventually causes cell death [12,15].…”

“…In studies with gram negative, E. coli, and gram positive, Staphylococcus aureus, Kim et al [2] reported greater biocidal efficiency of silver nanoparticles for E. coli, and attributed it to difference in cell wall structure between gram negative and gram positive microorganisms. However, currently there is insufficient evidence to support such conclusions since most research on bactericidal effect of nanoparticles has been conducted with one or a very limited number of microbial strains [12][13][14][15].…”

Ipomea carnea-based silver nanoparticle synthesis for antibacterial activity against selected human pathogens

“…However, it possesses polyphenols and alkaloids that can be utilised as reducing agents in the synthesis of nanoparticles. The antimicrobial properties of nanoparticles are well established, and a mechanism of inhibition has been proposed by several researchers [14][15][16][17]. Silver is used traditionally as a disinfecting agent in medicine and as a culinary agent [18].…”

Preparation of colloidal silver nanoparticles in poly(N-vinylpyrrolidone) by γ-irradiation

“…The antibacterial activity of silver-containing materials such as polyurethane foam can be used for water treatment [9].…”