Safe Functional Modified CuO Nanoparticles?

CuO nanoparticles produced by methods from inorganic chemistry and physics are applied as biocides and applications thereof in solar stills, solar collectors, catalysis, sensing and diesel fuels have been proposed. Such CuO nanoparticles are hazardous due to the release of Cu ions and the induced generation of reactive oxygen species after uptake by organisms. Nanoparticle hazard may be reduced by surface modification (coating or capping) and doping which reduces the release of Cu ions and the generation of reactive oxygen species. None of the published safe-by-design modifications of CuO nanoparticles that will be discussed here have been proven safe (no risk). By targeting the release of Cu ions and the generation of reactive oxygen species by CuO nanoparticles, safe(r)-by-design studies target properties that underly the biocidal functionality of CuO nanoparticles. Other functionalities of CuO nanoparticles may also be impacted. There is a case for complementing safe(r)-by-design studies by investigating the impact of the modifications studied on CuO nanoparticle functionality.</p

Mapping individual electromagnetic field components inside a photonic crystal

We present a method to map the absolute electromagnetic field strength inside photonic crystals. We apply the method to map the electric field component Ez of a two-dimensional photonic crystal slab at microwave frequencies. The slab is placed between two mirrors to select Bloch standing waves and a subwavelength spherical scatterer is scanned inside the resulting resonator. The resonant Bloch frequencies shift depending on the electric field at the position of the scatterer. To map the electric field component Ez we measure the frequency shift in the reflection and transmission spectrum of the slab versus the scatterer position. Very good agreement is found between measurements and calculations without any adjustable parameters.Comment: 12 pages, 7 figure