Limits...
Antibacterial property of Ag nanoparticle-impregnated N-doped titania films under visible light.

Wong MS, Chen CW, Hsieh CC, Hung SC, Sun DS, Chang HH - Sci Rep (2015)

Bottom Line: However, the major limitation of this Ag-TiO2 composite material is its durability; the antibacterial property decreased markedly after repeated use.Here we revealed that the antibacterial durability of these thin films is substantially improved in both the dark and visible light, by which bacteria, such as Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, and Acinetobacter baumannii, could be efficiently eliminated.This study demonstrated a feasible approach to improve the visible-light responsiveness and durability of antibacterial materials that contain silver nanoparticles impregnated in TiO2(N) films.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Materials Science and Engineering, National Dong Hwa University, Hualien, Taiwan [2] Nanotechnology Research Center, National Dong Hwa University, Hualien, Taiwan.

ABSTRACT
Photocatalysts produce free radicals upon receiving light energy; thus, they possess antibacterial properties. Silver (Ag) is an antibacterial material that disrupts bacterial physiology. Our previous study reported that the high antibacterial property of silver nanoparticles on the surfaces of visible light-responsive nitrogen-doped TiO2 photocatalysts [TiO2(N)] could be further enhanced by visible light illumination. However, the major limitation of this Ag-TiO2 composite material is its durability; the antibacterial property decreased markedly after repeated use. To overcome this limitation, we developed TiO2(N)/Ag/TiO2(N) sandwich films in which the silver is embedded between two TiO2(N) layers. Various characteristics, including silver and nitrogen amounts, were examined in the composite materials. Various analyses, including electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and ultraviolet-visible absorption spectrum and methylene blue degradation rate analyses, were performed. The antibacterial properties of the composite materials were investigated. Here we revealed that the antibacterial durability of these thin films is substantially improved in both the dark and visible light, by which bacteria, such as Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, and Acinetobacter baumannii, could be efficiently eliminated. This study demonstrated a feasible approach to improve the visible-light responsiveness and durability of antibacterial materials that contain silver nanoparticles impregnated in TiO2(N) films.

No MeSH data available.


Related in: MedlinePlus

Bactericidal activity analysis after repeated use.Bactericidal activities of the single layer or sandwich (multilayer) thin films with (light) or without (dark) visible-light illumination after used for 1 (1 st), 2 (2nd) and 3 (3rd) times were shown. Respective single layer-dark groups were normalized to 100%. ††P < 0.01 compared to respective dark groups; **P < 0.01 compared to respective single layer groups.
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f6: Bactericidal activity analysis after repeated use.Bactericidal activities of the single layer or sandwich (multilayer) thin films with (light) or without (dark) visible-light illumination after used for 1 (1 st), 2 (2nd) and 3 (3rd) times were shown. Respective single layer-dark groups were normalized to 100%. ††P < 0.01 compared to respective dark groups; **P < 0.01 compared to respective single layer groups.

Mentions: The visible-light-responsive antibacterial property of these novel sandwich films after repeated usages was compared with that of our previously developed single-layer thin films containing Ag nanoparticles6. Although the first use of the single-layer thin films could achieve an approximately 5-log reduction in bacteria6, the data indicated that these thin films could not efficiently eliminate the bacteria after frequently use (Fig. 6, second- and third-cycle use of single-layer groups). By contrast, favorable performance was observed after these multilayer films were repeated used, which eliminated E. coli efficiently after the second and third use (Fig. 6, second- and third-cycle use of multilayer groups). Scanning electron microscopy was employed to investigate the E. coli cell damage caused by the sandwich films. We observed that if the bacterial cells were not treated with Ag present in the N-doped TiO2 sandwich films with or without visible light illumination, they displayed relatively smooth surfaces (Fig. 7A,B). Because of the antibacterial property of Ag, bacterial cells displayed rough surfaces after being treated with a sandwich film in the dark (Fig. 7C). More vigorous changes, which were showed as unique cracks, such as structures on their surfaces, were observed after the bacterial cells were illuminated with visible light on a sandwich film (Fig. 7D, arrows).


Antibacterial property of Ag nanoparticle-impregnated N-doped titania films under visible light.

Wong MS, Chen CW, Hsieh CC, Hung SC, Sun DS, Chang HH - Sci Rep (2015)

Bactericidal activity analysis after repeated use.Bactericidal activities of the single layer or sandwich (multilayer) thin films with (light) or without (dark) visible-light illumination after used for 1 (1 st), 2 (2nd) and 3 (3rd) times were shown. Respective single layer-dark groups were normalized to 100%. ††P < 0.01 compared to respective dark groups; **P < 0.01 compared to respective single layer groups.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496671&req=5

f6: Bactericidal activity analysis after repeated use.Bactericidal activities of the single layer or sandwich (multilayer) thin films with (light) or without (dark) visible-light illumination after used for 1 (1 st), 2 (2nd) and 3 (3rd) times were shown. Respective single layer-dark groups were normalized to 100%. ††P < 0.01 compared to respective dark groups; **P < 0.01 compared to respective single layer groups.
Mentions: The visible-light-responsive antibacterial property of these novel sandwich films after repeated usages was compared with that of our previously developed single-layer thin films containing Ag nanoparticles6. Although the first use of the single-layer thin films could achieve an approximately 5-log reduction in bacteria6, the data indicated that these thin films could not efficiently eliminate the bacteria after frequently use (Fig. 6, second- and third-cycle use of single-layer groups). By contrast, favorable performance was observed after these multilayer films were repeated used, which eliminated E. coli efficiently after the second and third use (Fig. 6, second- and third-cycle use of multilayer groups). Scanning electron microscopy was employed to investigate the E. coli cell damage caused by the sandwich films. We observed that if the bacterial cells were not treated with Ag present in the N-doped TiO2 sandwich films with or without visible light illumination, they displayed relatively smooth surfaces (Fig. 7A,B). Because of the antibacterial property of Ag, bacterial cells displayed rough surfaces after being treated with a sandwich film in the dark (Fig. 7C). More vigorous changes, which were showed as unique cracks, such as structures on their surfaces, were observed after the bacterial cells were illuminated with visible light on a sandwich film (Fig. 7D, arrows).

Bottom Line: However, the major limitation of this Ag-TiO2 composite material is its durability; the antibacterial property decreased markedly after repeated use.Here we revealed that the antibacterial durability of these thin films is substantially improved in both the dark and visible light, by which bacteria, such as Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, and Acinetobacter baumannii, could be efficiently eliminated.This study demonstrated a feasible approach to improve the visible-light responsiveness and durability of antibacterial materials that contain silver nanoparticles impregnated in TiO2(N) films.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Materials Science and Engineering, National Dong Hwa University, Hualien, Taiwan [2] Nanotechnology Research Center, National Dong Hwa University, Hualien, Taiwan.

ABSTRACT
Photocatalysts produce free radicals upon receiving light energy; thus, they possess antibacterial properties. Silver (Ag) is an antibacterial material that disrupts bacterial physiology. Our previous study reported that the high antibacterial property of silver nanoparticles on the surfaces of visible light-responsive nitrogen-doped TiO2 photocatalysts [TiO2(N)] could be further enhanced by visible light illumination. However, the major limitation of this Ag-TiO2 composite material is its durability; the antibacterial property decreased markedly after repeated use. To overcome this limitation, we developed TiO2(N)/Ag/TiO2(N) sandwich films in which the silver is embedded between two TiO2(N) layers. Various characteristics, including silver and nitrogen amounts, were examined in the composite materials. Various analyses, including electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and ultraviolet-visible absorption spectrum and methylene blue degradation rate analyses, were performed. The antibacterial properties of the composite materials were investigated. Here we revealed that the antibacterial durability of these thin films is substantially improved in both the dark and visible light, by which bacteria, such as Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, and Acinetobacter baumannii, could be efficiently eliminated. This study demonstrated a feasible approach to improve the visible-light responsiveness and durability of antibacterial materials that contain silver nanoparticles impregnated in TiO2(N) films.

No MeSH data available.


Related in: MedlinePlus