Background:
The small size of nanoplastics (NPs; <1 µm in diameter) facilitates airborne transport, inhalation, and deposition in the lungs, raising significant concerns about potential effects on human health. In occupational settings, such as waste management and recycling facilities, exposure to NPs carrying microbial contaminants may pose an additional health risk to workers. In the present study, we investigated pulmonary cytotoxicity and pro-inflammatory responses after exposure to polyethylene terephthalate nanoplastics (PET-NPs) with or without microbial contaminants.
Methods:
PET-NPs were synthesized from a post-consumer juice bottle (PET b001) and commodity PET pellets (PET c000). The presence of microbial contaminants was assessed via receptor activation in HEK293 Toll-like receptor (TLR) reporter cells expressing TLR2 or TLR4. Co-cultures of human alveolar epithelial cells (A549) and monocyte-derived macrophages (dTHP-1) were exposed to PET-NPs (0, 10 or 100 μg/mL) that tested either negative or positive for TLR2 and TLR4 activation. After 24 h, cell viability was measured, and cytokine responses were quantified at both mRNA and protein levels.
Results:
PET b001 activated TLR2 and TLR4, indicating the presence of biologically active microbial components, whereas PET c000 showed no activation. In A549/dTHP-1 co-cultures, PET b001 (10 and 100 μg/mL) significantly increased IL-1B, IL-6, IL-8, and TNF mRNA levels and IL-6 [...]