While you are absolutely correct that nanoparticles need to be used with caution, it might be difficult for a superhydrophobic particle to enter a body that it

While you are absolutely correct that nanoparticles need to be used with caution, it might be difficult for a superhydrophobic particle to enter a body that it is so repulsed by. But I can imagine them being quite harmful when they nevertheless find a way in. An interesting consideration: testing potentially harmful products on the public is done with many technologies. I am guessing the public benefits from this often enough to justify continuing the practice. Compare this "easier to ask for forgiveness than permission" style to the public utility lost by performing rigorous governmental approval and costly testing of the likes that pharmaceutics pass through before market entry.