Fig. 1

Biodistribution of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) after vitelline vein (IV) or intra-amniotic (IA) delivery. a Stereomicroscope image of a glass micropipette injecting NPs loaded with coumarin 6 (C6, green) into the vitelline vein at E15.5 (top), NPs in E15.5 fetal circulation 3 h after vitelline vein delivery (middle), and intra-amniotic injection of C6 NPs at E16.5 (bottom) (n = 69 fetuses IV; n = 140 fetuses IA). Images are representative screen captures from full movies that are available in the supplementary materials (Supplementary Movies 1–3). Scale bars = 5 mm. b–d Distribution of DiD-loaded PLGA NPs 3 h after either IV or IA fetal injection in (b) time-dated pregnant B6 mice before delivery (top) and post surgical delivery of injected fetuses (bottom), (c) individual fetuses, and (d) fetal organs (control n = 9 fetuses, E15.5 IV n = 10 fetuses, E16.5 IV n = 7 fetuses, E15.5 IA n = 7 fetuses, E16.5 IA n = 8 fetuses, E17.5 IA n = 9 fetuses, E18.5 IA n = 10 fetuses). Scale bars = 2 mm