Cellular Uptake, Transport, and Organelle Response After Exposure to Microplastics and Nanoplastics: Current Knowledge and Perspectives for Environmental and Health Risks

Microplastics (MPs) and nanoplastics (NPs) pollution has become an increasingly serious environmental problem, drawing widespread attentions. Owing to the small size, they could be potentially accumulated and translocated in different organs, tissues, and organelles of organisms and human beings, which in turn possibly causes adverse effects on human health. Some of the organelles are very sensitive to environmental pollutants, including MPs and NPs. In this review, we summarized and discussed the cellular uptake, intracellular transport, and induced organelle response of MPs and NPs. We first discussed the cellular uptake pathways, as well as the intracellular transportation, of MPs and NPs at sizes ranging from tens of nanometers to microns. Both endocytosis and passive diffusion were required for the cellular uptake of MPs and NPs. In the cells, some organelles, such as endosome, autophagosome, and lysosome, were involved in MPs and NPs transportation. We further introduced the roles of different organelles in toxicity induction of MPs and NPs and the relevant influencing factors including plastic size, surface modification, exposure concentration, and exposure model. The organelles of mitochondria, endoplasmic reticulum, nucleus, and cytoskeleton played important roles in the toxicity induction of MPs and NPs toxicity. Moreover, we proposed further research perspectives with the concern of environmental control and health risk assessment. Owing to the long-term existence of MPs and NPs, the control of production and environmental monitoring of MPs and NPs at the cellular level should be taken into consideration in the future.