Human placental exposure to pollutant nanoparticles: uptake, translocation and functional impact

Nanoparticles are abundant in the natural environment as a result of an exponential increase in the production of engineered particles and pollutants. Due to their small size, nanoparticles can cross mucosal barriers, entering the blood stream and reaching a variety of different tissue types. Pregnant women and their developing fetuses are particularly vulnerable to nanoparticles, with the placenta acting as the critical barrier for fetal exposure. It has not yet been determined how protective the placental barrier is against nanoparticle translocation, with conflicting evidence regarding the mechanisms of nanoparticle uptake and the physicochemical factors that influence their transport. Here we summarise current findings on nanoparticle transit across the placenta and the associated impacts on placental development and function. Together, these insights highlight key considerations for future research in this area.