Matricaria chamomilla flowers were incubated
with
gold nanoparticles of different sizes ranging from 1.4 to 94 nm. After
different incubation times of 6, 12, 24, and 48 h, the gold distribution
in the flowers was destructively measured by inductively coupled plasma
mass spectrometry (ICP-MS) and non-destructively measured by X-ray
fluorescence imaging (XFI) with high lateral resolution. As a control,
the biodistribution of iodine ions or iodine-containing organic molecules
(iohexol) was determined, in order to demonstrate the feasibility
of mapping the distribution of several elements in parallel. The results
show a clear size-dependent transport of the nanoparticles. In addition,
the surface chemistry also plays a decisive role in disposition. Only
the 1.6 nm nanoparticles coated with acetylcysteine could be efficiently
transported through the stem of the flowers into the petals. In this
case, almost 80% of the nanoparticles which were found within each
flower were located in the petals. The study also highlights the potential
of XFI for in situ recording of in vivo analyte biodistribution.