Figure 1.

Concept of quantitative nanoparticle biokinetics. Nanoparticles (NP) are administered at time t = 0. From this time point on, the entire urinary and fecal excretions are collected separately. Animals are euthanized at times t₁, t₂, t₃, etc., and organs and tissues of interest as well as the entire remaining carcass are sampled (100% balanced sampling). Samples require special preparation before chemical analysis, e.g. by inductive-coupled-plasma mass spectroscopy (ICP-MS). When nanoparticles are radio-labeled, samples will be analyzed directly, without any further preparation. Reprinted with permission from [21].