5 The effect of ENPs on biological cells, the environment and human health, are under active research and not yet fully understood, 6 which also implies regulatory problems.
3 The potential risks associated with this exposure 4 are driving research into the basic physical chemistry of ENPs as well as their interaction with biological materials. 1 Introduction Due to the ubiquitous use of nanoparticles in food and consumer products, 1,2 human exposure to engineered nanoparticles (ENPs) has recently become an important issue in the field of health and environmental science. While SAXS offers excellent precision and traceability to the SI unit system if the model fitting approach is used for data analysis, CLS provides detailed size distributions from which additional information on the agglomeration state can be deduced.
With SAXS and CLS, the measured size of the primary particles was mostly unchanged. For the methods based on light scattering, DLS and PTA, the size distributions obtained were significantly altered due to the formation of a protein corona and induced agglomeration effects. The effect of the biological dispersion medium on the modal value of the particle size distribution was compared for each method taking into account the estimated uncertainty. The test samples were measured by all methods immediately after dispersion and after incubation at room temperature for 24 h. Plain and aminated silica nanoparticles dispersed in purified water, in 50 mM Tris–HCl buffer and in cell culture medium were measured using dynamic light scattering (DLS), centrifugal liquid sedimentation (CLS), small-angle X-ray scattering (SAXS), and particle tracking analysis (PTA).