Inhaled nanoparticles – human-made specks so minuscule they can’t be seen in conventional microscopes, found in thousands of common products – can cross a natural, protective barrier that normally protects fetuses, according to Rutgers University scientists studying factors that produce low-birth-weight babies. Reporting in the medical journal Placenta, Stapleton and colleagues tracked the movement of nanoparticles made of metal titanium dioxide through the bodies of pregnant rats. After the nanoparticles were inhaled into the lungs of the rodents, some of them escaped this initial barrier. From there, the particles flowed through the placentas, which generally filter out foreign substances to protect the fetus. But the placenta does not act as a barrier to these particles. Nor do the lungs.”

Most nanoparticles are engineered, with few produced naturally. These particles are used in thousands of products, from sunscreens to pharmaceuticals to sports equipment. They are highly valued because they can enhance the effectiveness of drugs and produce sturdy-though-lightweight products.

The research emerged from investigations into the causes of low birth weight in human infants. Newborns weighing less than 5.5 pounds can suffer adverse health effects as infants and throughout their lives. According to Stapleton, one theory is mothers who give birth to babies with low birth weights may have inhaled harmful particulates. The resulting inflammation may affect bodily systems, such as blood flow in the uterus, that could inhibit growth of the fetus. “Now that we know that the nanoparticles migrate – from the mother’s lungs to the placenta and fetal tissues – we can work on answering other questions,” Stapleton said. “This detail of transfer will help inform future studies of exposure during pregnancy, fetal health, and the developmental onset of disease.”

Other Rutgers authors on the paper included Brian Buckley and Cathleen Doherty at the Environmental and Occupational Health Sciences Institute, and Jeanine D’Errico and Jarett Reyes George at the Ernest Mario School of Pharmacy.