• nanoparticles;
  • angiogenesis;
  • pharmacokinetics;
  • embryos;
  • drug delivery
Thumbnail image of graphical abstract

D. Cramb* and co-workers report on page 3118 that nanoparticles circulating in angiogenic tissue partition into surrounding tissues through fenestrations in the blood vessel walls, depending on the nanoparticle properties. The dependence of the portioning rate on nanoparticle size suggests that the mechanism is largely controlled by geometry and that the angiogenic blood vessels function like a size exclusion filter. This work provides insight into the mechanism of nanoparticle deposition into angiogenic tissues while also presenting a new biological model that can accelerate our understanding of nanoparticle toxicity and tumor targeting.