Zebrafish Chorion Nanoparticle Barrier (2D)

Before a zebrafish embryo hatches, the only way anything from the outside world reaches it is through the pore canals of its chorion — an acellular shell whose pores run about 0.5 to 0.7 micrometres across. This 2D cross-section simulator streams nanoparticles toward the chorion boundary and checks each arrival's effective diameter (primary size scaled up by how agglomerated the particles are in the surrounding medium) against the pore-size distribution using a logistic pass-probability model. Particles small and well-dispersed enough slip through into the perivitelline space and accumulate as internal dose; particles that are too large — often because higher ionic strength drove them to agglomerate — are physically excluded and pile up on the chorion's outer boundary. Drag the main view to pan and scroll to zoom; the probability curve and dose-history strip chart update live alongside the particle field.