Nanoplastics are tiny plastic particles measured at the nanometer scale, which may be capable of crossing the blood-brain barrier, according to ongoing computational research at Baruch College.
Jessica Zhou, a junior majoring in psychology, is running molecular simulations in professor Baofu Qiao’s lab to determine how four common plastics interact with the blood-brain barrier, the brain’s primary protective membrane.
The study was prompted by a previous paper that found traces of microplastics inside preserved human brain samples.
“It’s everywhere and you’re always eating it, you’re breathing it in,” Zhou told The Ticker. “But the one place where you wouldn’t expect it to be was in the brain.”
Using software tools including GROMACS, CHARMM-GUI and VMD, the team simulated nanoparticles of polyethylene, polypropylene and polystyrene attempting to penetrate two membranes: a blood-brain barrier model and a general cell membrane made of POPC lipids for comparison.
The physics of the simulation so far show that both polyethylene and polypropylene are highly energetically favorable for membrane penetration, suggesting they naturally tend to enter. Polystyrene also showed penetration, but to a lesser extent.
Polyethylene displayed the most notable behavior. As it approached the membrane, it rotated from a horizontal to a vertical orientation before embedding itself inside.
“PE starts going vertically before entering the membrane that way,” Zhou said. “We believe that’s why this crystalline structure was able to enter the membrane so easily, even though it was more polar than PS and PP.”
A fourth plastic, called polyethylene terephthalate, was tested but excluded from the paper’s main findings.
Its highly polar molecular structure, caused by oxygen-heavy ester chains, made membrane penetration energetically unfavorable across multiple simulation runs.
The research also examined what happens after a nanoparticle enters the membrane.
Simulations showed that polypropylene and polystyrene particles, both amorphous in structure, became deformed over time inside the bilayer, with polystyrene also beginning to dissolve once embedded.
The membrane itself was shown to expand after each nanoparticle was embedded, an effect observed across all plastics tested.
This was especially pronounced with polyethylene terephthalate, which researchers believe may facilitate further permeation of nanoplastics into the membrane.
Zhou acknowledged the study’s current limitations. The simulations are theoretical and wet lab work will be needed to confirm the findings.
“The more findings, the better,” she said.
Zhou credited Qiao as the inspiration behind her development as a researcher.
After completing General Chemistry 1, she joined his lab with no prior research experience. Over several semesters, Qiao walked her through every step of the process, from setting up simulations to writing for publication.
Fellow lab member Annemarie Ianos, a senior majoring in biological sciences, also played a role. Zhou cited her scientific writing style as a major influence during the manuscript drafting process.
The project is part of a broader, multiphase research effort. The second phase, which Zhou is currently working on, examines the effects of cholesterol levels in cell membranes on nanoparticle penetration, the effects of polymer size, other crossing mechanisms and the possibility of spontaneous assembly of the polymer.
The final phase aims to apply the findings toward therapeutic design, potentially developing molecules that could block nanoplastics from entering cell membranes — a direction inspired by previous microplastic-peptide tagging research.
Zhou will present the findings at the American Chemical Society in the fall. It is one of the largest chemistry conferences in the nation.
For Zhou, the project connects to a longtime personal interest in environmental sustainability.
“My childhood self would be relieved,” she said. “She would be like, ‘wow, thank God I’m able to do something.’”
