Photocatalytic and antibacterial activities of silver and iron doped titania nanoparticles in solution and polyaspartic coatings

Nanotechnology. 2019 Feb 22;30(8):085706. doi: 10.1088/1361-6528/aaf512. Epub 2018 Nov 30.

Abstract

Visible region active photocatalytic coatings are of interest for antimicrobial activity in low light applications or those employing LED lights with limited UV content. This work examined Ag and Fe doped titania nanoparticles (nTiO2) with varying dopant ranges in polyaspartic polymer coatings for potential light and dark activity. First, the Ag and Fe doped nTiO2 were synthesized by sol-gel chemistry with varying dopant concentrations, then characterized with respect to their size and aggregate size distribution, crystallinity, and surface and band gap features. The photocatalytic activity was then tested with methylene blue under both AM 1.5 G and visible light. From both sample sets (Ag and Fe doped nTiO2), the best photo catalytically active sample materials were chosen for antibacterial tests with gram-negative Escherichia coli (E. coli) and gram-positive Bacillus subtilis (B. subtilis) in (a) solution and (b) polyaspartic nanocomposites under UV and visible irradiation. The results showed that Ag doped nTiO2 samples delivered the best and excellent antibacterial action, even in the dark, attributed to both an enhanced band gap and surface area, as well as a combination of photocatalytic activity and Ag being present at the nanoparticle's surface. No leaching of Ag at room temperature was observed from the nTiO2 structure, giving potential for next generation coatings that are both light and dark active.

MeSH terms

  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / pharmacology
  • Bacillus subtilis / drug effects
  • Bacillus subtilis / radiation effects
  • Catalysis
  • Escherichia coli / drug effects
  • Escherichia coli / radiation effects
  • Escherichia coli Infections / drug therapy
  • Humans
  • Iron / chemistry*
  • Iron / pharmacology
  • Light
  • Nanoparticles / chemistry*
  • Nanoparticles / ultrastructure
  • Silver / chemistry*
  • Silver / pharmacology
  • Titanium / chemistry*
  • Titanium / pharmacology
  • Ultraviolet Rays

Substances

  • Anti-Bacterial Agents
  • titanium dioxide
  • Silver
  • Titanium
  • Iron