Nanoparticles are regarded as a promising therapeutic anti-cancer agent in treatment
of head and neck tumours. On the way to clinical use the evaluation of toxicity is
a central obstacle. However, animal experiments are associated with high costs and
bureaucratic barriers. The Chorionallantoic Membrane-Assay (CAM-Assay) may offer an
attractive alternative with low costs, no necessity of an ethics committee approval
for animal experimentation and simple experimental conditions.
In order to analyse a possible organ-specific accumulation of therapeutically applied
nanoparticles, we injected ZnO@SiO2 nanoparticles.
Fertilized hen's eggs were incubated and opened during the experiment, providing access
to the chorionallantoic membrane, which could be seen as an equivalent of mammalian
placenta.
On day 10 of incubation, ZnO@SiO2 nanoparticles (FITC-labelled) or NaCl (control) were injected. After 7h and 24h we
fixated CAM, brain, heart, liver and kidney. The samples were histologically processed
afterwards and appraised with confocal microscopy.
We could detect accumulation of ZnO@SiO2 nanoparticles in the heart, liver and kidney after 7h and 24h, respectively, while
examination of brain and CAM showed no nanoparticular accumulation. Kidney and liver
showed frequent accumulation while the heart only showed single particles. Our data
suggests that accumulation of nanoparticles occurs mainly in organs with high blood
flow. However, the brain appears to be sufficiently protected, which may be due to
mechanisms such as the blood-brain-barrier.
Our experiments demonstrate that the CAM-Assay is a promising model for the analysis
of nanoparticular agent's accumulation, possible even for those therapeutically applied.
