Proceedings of the National Academy of Sciences · 2019 · 120 citations · 60 references
Naturally occurring magnetic nanoparticles have been detected in human cells, but their origin and role remain unknown. The study observes long‑term transformations of man‑made magnetic nanoparticles internalized in human stem cells to reveal a mechanism of assimilation. Stem cells first degrade the nanoparticles, then synthesize new magnetic nanoparticles in situ from the released iron. The remagnetization occurs via specific pathways involving ferritin and appears linked to a detoxification response to iron excess, providing direct experimental proof that human cells can synthesize magnetic nanoparticles.
Significance Naturally occurring magnetic nanoparticles have been detected in human cells; however, their origin and role remain unknown. In the present paper, the observation of long-term transformations of man-made magnetic nanoparticles internalized in human stem cells displays a mechanism regarding their assimilation. Indeed, the nanoparticles are first degraded by the stem cells, and then new magnetic nanoparticles are synthesized in situ from the released iron. This “remagnetization” phenomenon is observed under specific pathways only, involves the ferritin protein, and seems linked to a detoxification mechanism in case of iron excess. It also brings a direct experimental proof that magnetic nanoparticles can be synthesized by human cells.
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Superparamagnetic iron oxide: pharmacokinetics and toxicity
Ralph Weissleder, DD Stark, BL Engelstad et al. · American Journal of Roentgenology · 1989 · 1K citations · Full text