Common plastics, such as polyethylene terephthalate (PET), as pollutants in aquatic environments in the form of micro/nanoparticles are of environmental and public health concern.

Plastic pollution is a major environmental concern due to its pervasiveness which continues to increase year on year, as a result of a continuing acceleration in global plastic production and use. Polyethylene terephthalate (PET) is among the most produced plastics, commonly used as food and beverage containers. Once released in the environment, the degradation of plastic materials produces micro-and nano-plastics, with a particular concern about potential toxicological effects if they cross epithelial barriers via inhalation or ingestion. In this work, the effect of PET nanoparticles (PET-NPs) (≤ 250 d.nm) was assayed on mouse macrophages cell line (RAW 264.7) in in vitro experiments. Results showed that PET nanoparticles were easily internalized by the cells, 15 μg/mL of nanoparticles concentration had exhibited effects in cell proliferation and a slightly increased production of Reactive Oxygen Species (ROS), which seems to trigger cell response as foreign particles related to upregulation of PCDH12, IGH-V10, ROBO1 genes, and cell maintenance functions, related to FTSJ2 gene upregulation. Thus, the RAW 264.7 results showed here are useful towards for a preliminary and understanding of the potentially toxic effects related to PET nanoparticles and complementary to other in vitro assays, as the first step into the development of the risk assessment framework.