Shedding Light on Metal-Based Nanoparticles in Zebrafish by Computed Tomography with Micrometer Resolution

Supplementary 3D image stacks of microtomography data.

100 layer xy, xz, and yz image stacks

Publication included as PDF file (open access, DOI: 10.1002/smll.202000746)

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Metal-based nanoparticles are clinically used for diagnostic and therapeutic
applications. After parenteral administration, they will distribute throughout
different organs. Quantification of their distribution within tissues in the 3D
space, however, remains a challenge owing to the small particle diameter.
In this study, synchrotron radiation-based hard X-ray tomography (SRμCT)
in absorption and phase contrast modes is evaluated for the localization of
superparamagnetic iron oxide nanoparticles (SPIONs) in soft tissues based
on their electron density and X-ray attenuation. Biodistribution of SPIONs
is studied using zebrafish embryos as a vertebrate screening model. This
label-free approach gives rise to an isotropic, 3D, direct space visualization
of the entire 2.5 mm-long animal with a spatial resolution of around 2
μm. High resolution image stacks are available on a dedicated internet
page (http://zebrafish.pharma-te.ch). X-ray tomography is combined with
physico-chemical characterization and cellular uptake studies to confirm the
safety and effectiveness of protective SPION coatings. It is demonstrated
that SRμCT provides unprecedented insights into the zebrafish embryo
anatomy and tissue distribution of label-free metal oxide nanoparticles.