U. professor finds MNPs in newborn rats, outlines implications for public policy

Phoebe Stapleton, an associate professor in the Department of Pharmacology and Toxicology, published a paper about the detection of micro- and nanoplastic particulates (MNPs) in neonatal rats after mothers inhaled the particles throughout their pregnancies, according to a University press release.

She described MNPs as tiny fragments of plastic no longer than five millimeters, and nanoplastics are a subset of microplastics less than 100 nanometers, or one micrometer, in size.

"Particles in this size range are invisible to the naked eye, but scientists have identified that particles in this range have a greater toxicological potential," she said.

According to the study, MNPs have been found within numerous vital organs such as the heart, liver, kidney and lungs, hinting at their ability to penetrate biological barriers.

Stapleton focuses on how maternal inhalation of these particles during pregnancy affects fetal development and makes the offspring more susceptible to diseases. She studied the duration that these MNPs accumulated within newborns' tissues in particular.

In the study, Stapleton exposed a cohort of pregnant rats to aerosolized, food-grade polyamide 12, or PA-12 plastic, while the control rats received no exposure. She distinguished between food-grade and non-food-grade plastic, as food-grade material is considered safe for use with foods, whereas non-food-grade fails to meet the safety criteria.

Then, her research team used a specialized hyperspectral dark field microscope that leverages refracted light and its distinct interaction with plastic to detect the particles.

"The wavelength of light that bounces back is unique, like a fingerprint, allowing us to identify our experimental particles," Stapleton said.

The study concluded that the MNPs accumulated in both male and female offspring throughout their neonatal development period in most major tissues. Ongoing studies are probing the mechanism and speed at which these MNPs cross the placental barrier, Stapleton explained.

Other key questions are the concentration of MNPs found in tissues and whether the cytotoxicity arising from this exposure results in disease outcomes.

Stapleton hopes this research informs public health and public policy officials to assess the risk of MNPs when drafting new policy changes. An example of recent policy to curb plastic pollution was in 2020 when Gov. Phil Murphy (D-N.J.) signed a bill banning single-use plastic and paper bags in all stores and food businesses in the state, according to a press release. 

"We're doing some interesting state-of-the-art science at Rutgers, focused on areas of current public concern," Stapleton said.