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

<p>Supplementary 3D image stacks of microtomography data.</p> <p>100 layer xy, xz, and yz image stacks</p> <p>Publication included as PDF file (open access, DOI: 10.1002/smll.202000746)</p> <p>********************************************</p> <p>Metal-based nanoparticles are clinically used for diagnostic and therapeutic<br> applications. After parenteral administration, they will distribute throughout<br> different organs. Quantification of their distribution within tissues in the 3D<br> space, however, remains a challenge owing to the small particle diameter.<br> In this study, synchrotron radiation-based hard X-ray tomography (SR&mu;CT)<br> in absorption and phase contrast modes is evaluated for the localization of<br> superparamagnetic iron oxide nanoparticles (SPIONs) in soft tissues based<br> on their electron density and X-ray attenuation. Biodistribution of SPIONs<br> is studied using zebrafish embryos as a vertebrate screening model. This<br> label-free approach gives rise to an isotropic, 3D, direct space visualization<br> of the entire 2.5 mm-long animal with a spatial resolution of around 2<br> &mu;m. High resolution image stacks are available on a dedicated internet<br> page (http://zebrafish.pharma-te.ch). X-ray tomography is combined with<br> physico-chemical characterization and cellular uptake studies to confirm the<br> safety and effectiveness of protective SPION coatings. It is demonstrated<br> that SR&mu;CT provides unprecedented insights into the zebrafish embryo<br> anatomy and tissue distribution of label-free metal oxide nanoparticles.</p>