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Keywords:

  • plasmonic nanoparticles;
  • nanocomposites;
  • photodynamic therapy;
  • hematoporphyrin;
  • Staphylococcus aureus

Abstract

We fabricated composite nanoparticles consisting of a plasmonic core (gold nanorods or gold–silver nanocages) and a hematoporphyrin-doped silica shell. The dual photodynamic and photothermal activities of such nanoparticles against Staphylococcus aureus 209 P were studied and compared with the activities of reference solutions (hematoporphyrin or silica-coated plasmonic nanoparticles). Bacteria were incubated with nanocomposites or with the reference solutions for 15 min, which was followed by CW light irradiation with a few exposures of 5 to 30 min. To stimulate the photodynamic and photothermal activities of the nanocomposites, we used LEDs (405 and 625 nm) and a NIR laser (808 nm), respectively. We observed enhanced inactivation of S. aureus 209 P by nanocomposites in comparison with the reference solutions. By using fluorescence microscopy and spectroscopy, we explain the enhanced antimicrobial effect of hematoporphyrin-doped nanocomposites by their selective accumulation in the vicinity of the bacteria. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)