Synthesis and Bioactivity of RGO/TiO₂-Noble Metal Nanocomposite Flakes

This study aims to describe the influence of adding graphene oxide to TiO₂-noble metal (Me=Ag, Au or Pd) composite nanoparticles on their bioactivity (formation of RGO/TiO₂-Me nanocomposite system). The obtained nanocomposite flakes and reference TiO₂-Me nanoparticles were characterized using SEM, HRTEM and XPS spectroscopy, N₂ sorption analysis and helium pycnometer. The analysis of the antibacterial properties of synthesized nanocomposites revealed a growth inhibiting effect of TiO₂-Ag particles on gram positive bacteria such as: Staphylococcus aureus, Sarcina lutea and Bacillus subtilis. In the case of nanocomposite flakes containing RGO the visible changes in bacteriostatic properties were observed, including unexpected reversal of the antimicrobial activity of silver-containing nanoparticles into the stimulation of growth of applied bacterial strains. The stimulation of growth was not observed for TiO₂-Au and Pd nanoparticles deposited on the surface of RGO.