Nanomaterial interference with early human placenta: Sophisticated matter meets sophisticated tissues

- Human data on nanomaterial interference with early placenta is extremely scarce and still insufficient for teratologic risk assessment.
- Intensive research focusing on the placental barrier in humans and in animals is required, to ensure timely identification of human nano-teratogens.
- Nano toxicology will probably modify, but certainly not completely alter, the established principles in developmental toxicology research.

Next to nothing is known about nanoparticle and nanofiber trafficking at the feto-maternal interface in early human pregnancy. As the first trimester is thought to be crucial for the further placental and fetal development, it will be important to assess the possible risks of nanomaterial exposures during this period. There are some intriguing observations in nanotoxicology, however, indicating certain differences between classical toxicology and nanotoxicology. To understand nanomaterial-biokinetics and placental toxicity in early gestation, the special architecture, the hypoxic condition, the bilayer of villous trophoblast, the plugging of spiral arteries and the contribution of intrauterine glands to nutrition, as well as the delicate immunologic situation at the implantation site, will have to be considered. Unless nano-specific biokinetics are properly understood, it will be difficult to ensure identification of potential “nano-thalidomides” among all the newly engineered nanoparticles and fibers, based on the models available in reproductive toxicology.