Interaction of micro(nano)plastics with extracellular and intracellular biomolecules in the freshwater environment

Plastic particles of diameters ranging from 1 nm to 5 mm are known as micro(nano)plastics (MNPs) and are frequently utilized in biomedical and consumer applications. As a result of unregulated disposal, physicochemical and biological degradation of plastic waste, MNPs are inevitably released into the aquatic environment and interact with extracellular biomolecules such as allochthonous and autochthonous natural organic matter (NOM), as well as intercellular biomolecules such as antibiotic resistance elements (AREs). Extracellular biomolecules are either degradation byproducts of NOM (e.g., humic acid-HA and fulvic acid-FA) or are produced by organisms as polymeric substances (e.g., DNA, carbohydrates, and proteins). After entering into the environment, MNPs may undergo encapsulation or coating by biomolecules, resulting in an eco-corona layer or bio-film formation, which alters the fate, bioreactivity, and possible environmental and human health consequences of plastic particles. With that said, this review summarized the research on the interaction of MNPs and biomolecules in the freshwater environment to highlight the sources, formation, and recent occurrence of MNPs in rivers and lakes, their interactions with extracellular and intercellular biomolecules, potential factors influencing those interactions, associated ecological and human health impacts, and last but not least, the current gaps and future research directions for a better understanding of the plastic particle-biomolecule interface and its implications under freshwater conditions.