Understanding the PET micro/nanoplastics as an environmental stressor on pancreatin enzyme: leaching and binding characterization by multi-spectroscopic and molecular docking examination, and the resulting impact on Escherichia coli

The deformation and leaching of substances from micro/nanoplastics under biotic and abiotic conditions is an important yet often overlooked issues for the environment and human health. Furthermore, their interaction with biomolecules can result in corona formation and the surface deformation of micro/nanoplastics. However, the interaction between micro/nanoplastics and biomolecules, e.g. pancreatin, and the resulting deformation/leaching mechanisms, as well as their biological impact, remains insufficiently understood. Therefore, this study aims to examine the deformation/leaching processes of micro/nanoplastics due to the action of the pancreatin. The interaction mechanism between micro/nanoplastics and pancreatin was investigated using multi-spectroscopic and molecular docking approaches. The deformation of micro/nanoplastics was tested based on their functional groups and structure, and their leaching into the pancreatin solution was assessed by measuring aromaticity and oxidative inputs. In addition, deformation and leaching effects of micro/nanoplastics on pancreatin were investigated using its structural characteristics (e.g. aromatic side chains, activity, and agglomeration), as well as bacterial toxicity using Escherichia coli (e.g. viability, biofilm, and oxidative stress). The Fluorescence and UV-VIS spectroscopic results, as well as molecular docking simulations, revealed interactions between micro/nanoplastics and pancreatin. Deformation of the micro/nanoplastics was confirmed using higher carbonyl and hydroxyl indices by ATR-FTIR, and removal and introduction signals by ¹H-NMR. The higher aromaticity and oxidative potential of the pancreatin indicated the leaching of chemicals from the micro/nanoplastics. Furthermore, the metabolic and oxidative responses of E. coli exposed to leachates were influenced by the deformation and leaching of micro/nanoplastics, as well as by the structural characteristics of the pancreatin.