Quantifying the origin of nanosilver ions and their antibacterial activity

G.A. Sotiriou, A. Meyer, J. Knijnenburg, S. Panke, S.E. Pratsinis
Particle Technology Laboratory, ETH Zurich, CH

Keywords: silver nanoparticles, Ag+ ion release, size effect


Nanosilver is prominent in nanotechnology products [1]. Concerns however about leached Ag ions from its surface into aquatic environments have challenged its broad use. The origin of these ions is explored here by conditioning the nanosilver surface immobilized on nanostructured silica [2] made by both wet and dry processes. Such nanosilver is characterized by electron microscopy, atomic absorption spectroscopy, X-ray diffraction and its Ag+ ion release in de-ionized water is monitored over time [3]. By comparing nanosilver size distributions to their leached or dissolved Ag+ ion concentrations, the latter match surface state of nanosilver, depending on nanosilver diameter. References [1] Sotiriou, G. A.; Pratsinis, S. E. Engineering nanosilver as an antibacterial, biosensor and bioimaging material. Curr. Opin. Chem. Eng. 2011, 1, 3-10. [2] Sotiriou, G. A.; Pratsinis, S. E. Antibacterial activity of nanosilver ions and particles. Environ. Sci. Technol. 2010, 44, 5649-5654. [3] Sotiriou, G. A.; Teleki, A.; Camenzind, A.; Krumeich, F.; Meyer, A.; Panke, S.; Pratsinis, S. E. Nanosilver on nanostructured silica: Antibacterial activity and Ag surface area. Chem. Eng. J. 2011, 170, 547-554.