Superparamagnetic Nanoparticles: A Biodistribution Study Using Xenopus laevis Embryos

Various in-vivo biological models have been proposed for studying the interactions of nanomaterials with biological systems. Recently, there has been a significant increase in interest in the use of non-mammalian embryos, such as the frog Xenopus laevis as valid models for research in nanomedicine. In the present work, we demonstrate that X. laevis is a powerful model for the study of the biodistribution of superparamagnetic nanoparticles (SPION), extensively used in biomedical field for cell separation, MRI diagnostics and magnetic drug-targeting. 10 nl of 25 mg/ml of SPIONs (nano-screen MAG/ARA 200 nm, Chemicell) were microinjected. The biodistribution of SPIONs, following cardiac or pronephros injection of anesthetized frog larvae at stage 37, was studied by both in-vivo florescence and by Prussian blue staining of paraffin sections of the larvae after 24, 48, 72 or 96 hours (at 14 °C). The study confirmed that SPIONs diffused from either injection site by blood stream to all larval organs, being still present after 96 hours of injection.