Investigation of the antibacterial effects of silver-modified TiO2 and ZnO plasmonic photocatalysts embedded in polymer thin films

Abstract

Nanosilver-modified TiO2 and ZnO photocatalysts were studied against methicillin-resistant Staphylococcus aureus on the surface and against naturally occurring airborne microorganisms. The photocatalysts/polymer nanohybrid films were prepared by spray coating technique on the surface of glass plates and on the inner surface of the reactive light source. The photoreactive surfaces were activated with visible light emitting LED light at λ = 405 nm. The optical properties of the prepared photocatalyst/polymer nanohybrid films were characterized by diffuse reflectance measurements. The photocatalytic properties were verified with the degradation of ethanol by gas chromatography measurements. The destruction of the bacterial cell wall component was examined with transmission electron microscope. The antibacterial effect of the photocatalyst/polymer nanohybrid films was tested with different methods and with the associated standard ISO 27447:2009. With the photoreactive coatings, an extensive disinfectant film was developed and successfully prepared. The cell wall component of S. aureus was degraded after 1 h of illumination. The antibacterial effect of the nanohybrid films has been proven by measuring the decrease of the number of methicillin-resistant S. aureus on the surface and in the air as the function of illumination time. The photocatalyst/polymer nanohybrid films could inactivate 99.9 % of the investigated bacteria on different thin films after 2 h of illumination with visible light source. The reactive light source with the inner-coated photocatalyst could kill 96 % of naturally occurring airborne microorganisms after 48 h of visible light illumination in indoor air sample. The TEM results and the microbiological measurements were completed with toxicity tests carried out with Vibrio fischeri bioluminescence bacterium.

Öntisztuló felületek alkalmazása szerves anyagok eliminálására, ill. biológiai rendszerek ártalmatlanítására

“…) Moreover, it was also presented that the obtained hybrid layer shows improved photocatalytic and antibacterial properties because the biocompatible and HAp microlamellae are potential candidates as support materials for the attached P25 TiO 2 photocatalyst NPs 18 . Functional surfaces with photocatalyst content can kill numerous microorganisms because of its photocatalytic properties and the strong photocatalytic activity of this hybrid thin films are reported in the literature 17,19,20,21 . Due to the appearance of reactive radicals, the photocatalyst particles can degrade many organic compounds and inactivate microorganisms via destroying the cell wall and their DNA, respectively.…”

“…4. ) 20 . The developed nanohybrid films have antibacterial properties even against Enterococcus faecalis (Fig.…”

TiO2/Ag–TiO2 Nanohybrid Films are Cytocompatible with Primary Epithelial Cells of Human Origin: An In Vitro Study

“…We studied two newly developed photocatalysts/polymer nanohybrid films: TiO 2copolymer and Ag-TiO 2 -copolymer containing 0.001% silver nanoparticles. Both were applied with the spray coating technique, and activated with LED light (λ = 405 nm).The photocatalytic antibacterial activity of TiO 2 and Ag-TiO 2 coatings was established previously, and it was found that the role of photocatalytic activity was dominant over the antibacterial effect of silver ions themselves 25 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 primary epithelial cells showed higher sensitivity than immortalized cell lines to inflammatory cytokines 27 . Endosseus dental implants are placed into the alveolar bone, but the transgingival parts are surrounded by soft tissues.…”

Emerging technologies for long-term antimicrobial device coatings: advantages and limitations

“…39,41,43,61,62,[87][88][89][90][91] By combining several materials, different groups have developed antibacterial coatings that are anticorrosive, 39,43 titanium dioxide has also been combined with both silver nanoparticles and zinc oxide (ZnO) to improve the broad-spectrum antibacterial coverage of the coating. 61,62 Selvam et al demonstrated that the ZnO in these coatings performed better against both S. aureus and E. coli than the TiO 2 and silver nanoparticles alone. 61 It is hypothesized that the ZnO enhances the antibacterial activity because it readily permeates bacterial membranes through the generation of hydrogen peroxide.…”

“…61 It is hypothesized that the ZnO enhances the antibacterial activity because it readily permeates bacterial membranes through the generation of hydrogen peroxide. 62 Furthermore, TiO 2 has been combined with copper to form antifungal coatings on titanium. 88 Summary.…”