Potential risk of aromatic microplastic fragments during urinary excretion

Area of Science:

• Environmental Science
• Toxicology
• Materials Science

Background:

• Microplastics (MPs) are ubiquitous environmental contaminants.
• Their transient presence in the human body is often assumed to be harmless.
• Understanding MP fate and toxicity requires considering their diverse physicochemical properties.

Purpose of the Study:

• To investigate how microplastic chemistry influences biological interactions and toxicity.
• To compare the effects of alkyl polypropylene (PP) and aromatic polyethylene terephthalate (PET) MPs in a human blood model.
• To elucidate the pathway of microplastic-induced cellular stress along the circulation-to-excretion axis.

Main Methods:

• Exposure of human blood to biosphere-mimicked PP and PET microplastic fragments.
• Analysis of protein corona formation and red blood cell adsorption.
• Assessment of microplastic adhesion to endothelial and epithelial cells.
• Measurement of intracellular reactive oxygen species (ROS) and apoptosis markers.

Main Results:

• Polyethylene terephthalate (PET) formed a denser protein corona than polypropylene (PP) due to π-π interactions.
• PET exhibited significantly higher adsorption of serum proteins and red blood cells compared to PP.
• Protein-coated PET preferentially adhered to endothelial and epithelial cells, inducing higher ROS and apoptosis.
• Cell-type-specific disruptions were observed, linking vascular injury to urinary tract stress.

Conclusions:

• Microplastic physicochemical properties critically determine biological fate and toxicity.
• Aromatic microplastics, like PET, pose a greater risk due to enhanced protein binding and cellular interactions.
• These findings reveal an overlooked risk pathway and highlight the need for realistic exposure models for microplastic risk assessment.