Instrument Development for Nanomaterial Risk Assessment

Nanomaterials are a growing source for innovation. However, the very properties that make them so effective for their desired purpose might also render them more hazardous towards humans and the environment. Adequate risk assessment tools are often missing, partly due to instrumental gaps in exposure assessment and toxicity testing. In this thesis, two of these instrumental gaps served as the motivation to develop two new instruments, both with the purpose to reduce these gaps. The nano-PMC is a Particle Mass Classifier that is able to directly measure the mass of single particles down to a few zeptograms. Information about nanoparticle mass is vital for converting nanoparticle number concentrations to mass concentrations, a metric which is very useful for exposure assessment. In combination with mobility classification, the so-called apparent density of non-spherical particles like agglomerates can be measured, a property that might determine the health effect of non-toxic but biopersistent dust particles. The Cyto-TP is a thermal precipitator that deposits airborne nanoparticles onto living cells. Both the exposure mode and the cell configuration are designed to mimic the contamination of the pulmonary alveoli to inhaled nanoparticles. This instrument, as part of an in vitro inhalation toxicity test, might contribute to the reduction of the need for animal testing. Both instruments find application within a proposed test procedure to assess the risk potential of nanomaterials still in development - to promote safety-by-design. This precautionary approach might help to increase public confidence in nanomaterials.