Universal Correlation and Mechanism for the Antibacterial Activity of Silver Nanoparticles

Silver clusters (4-150 nm) anchored on nanostructured silica particles (300-400 m2/g) with closely controlled Ag content and size were made in one-step by scalable flame spray pyrolysis of Ag-nitrate and hexamethyldisiloxane containing solutions. Composite Ag/SiO2 nanoparticles were characterized by S/TEM, EDX spectroscopy, X-ray diffraction, N2 adsorption. The activity of such nanoparticles against the Gram negative bacterium Escherichia coli was investigated by monitoring the recombinantly synthesized green fluorescent protein. It is shown that higher Ag content particles exhibit a stronger antibacterial effect.