The antibacterial activity of nanosilver against Gram negative Escherichia coli bacteria is investigated by immobilizing nanosilver on nanostructured silica particles and closely controlling Ag content and size. These Ag/SiO2 nanoparticles were characterized by S/TEM, EDX spectroscopy, X-ray diffraction. The antibacterical activity of these composite samples was investigated for a constant composite particle concentration. The highest activity was observed for the higher silver content particles.

The topic of this study is focused on exposure control measures and working practices to minimize/eliminate potential health, safety, and environmental risks associated with the handling of dry nanoparticles. First, it is shown that a glove box with attached vacuum chamber for material transport and air cleaning is highly effective in minimizing occupational exposure to airborne nanoparticles. Second, the propensity for Baytubes C 150 P multi-walled carbon nanotubes to form airborne particles is found to be very low. The combined results provide useful guidelines for both the selection and the use of an engineering control to minimize/eliminate exposure to airborne carbon nanotubes, and nanoparticles in general.

Nanosized titanium dioxide (TiO2) and zinc oxide (ZnO) are widely used as inorganic sunscreen pigments. However, these metal oxide particles may also be photocatalytic and generate DNA-damaging reactive oxygen species. Therefore, we evaluated the photochemical properties of the whole sunscreen emulsions that contained nanoscale components and the inorganic particles derived from these sunscreens using several assays such as dichlorofluorescein fluorescence, the decolorization of Congo red dye and DMPO spin trap electron paramagnetic resonant spectroscopy. The results of these three tests showed that samples with ZnO nanoscale materials were more photoactive than the samples that contained TiO2 nanoparticles.