Interlaboratory comparison of nanoparticle size measurements between NMIJ and NIST using two different types of dynamic light scattering instruments.

The question of how to relate particle sizes measured using a fixed-angle dynamic light scattering (DLS) instrument with those measured using a multi-angle DLS instrument is addressed. A series of nearly monodisperse polystyrene latex (PSL) particles with nominal diameters of 100 nm, 70 nm, 50 nm, and 30 nm were measured using two different types of DLS instruments: one owned by the National Metrology Institute of Japan (NMIJ) of the multi-angle type and the other owned by the National Institute of Standards and Technology (NIST) of the fixed-angle type. The mean particle size of the PSL particles was measured using the multi-angle-type instrument at various scattering angles and at various concentrations of particle suspension.

Nanoscale reference materials for environmental, health and safety measurements: needs, gaps and opportunities.

The authors critically reviewed published lists of nano-objects and their physico-chemical properties deemed important for risk assessment and discussed metrological challenges associated with the development of nanoscale reference materials (RMs). Five lists were identified that contained 25 (classes of) nano-objects; only four (gold, silicon dioxide, silver, titanium dioxide) appeared on all lists. Twenty-three properties were identified for characterisation; only (specific) surface area appeared on all lists.

Development and evaluation of an aerosol generation and supplying system for inhalation experiments of manufactured nanoparticles.

Risk assessment of nanoparticles by inhalation experiments is of great importance since inhalation is considered the most significant route of exposure to nanoparticles suspended in air. However, there have been few inhalation experiments using manufactured nanoparticles, mainly because of the difficulty in stably dispersing the nanoparticles in air for a long period of time. In this study, we report for the first time the development of a rational system for stably and continuously dispersing and supplying manufactured nanoparticles for inhalation experiments.