The presence of microplastics[1] in all ecosystems is now well-documented, with multiple repercussions on marine life, ecosystems, and human health[2]. Could understanding the molecular basis of microplastic interactions with our environment help us devise new ways to limit this pollution?
At the macromolecular level, proteins—abundant in the environment—play a particularly important role in the integration of plastics into ecosystems. They adsorb onto the surface of micro- and nanoplastics, forming characteristic molecular structures around plastic particles, known as coronas. These structures directly influence particle behavior, especially their interactions with biological systems, with consequences for the health of living organisms.
The formation of coronas depends on both the surface properties of plastics and the structural and physicochemical characteristics of the amino acids that make up proteins. Researchers from our I2BC department and the LIONS laboratory (NIMBE/CEA-Iramis) have been studying this issue of protein-plastic interactions for several years. In a recent study published in the Journal of Physical Chemistry, they used molecular modeling to examine, at the atomic scale, the interactions between polyethylene nanoplastics—the most widely used plastic material in the world—and different amino acid sequences.
Their integrated approach, combining computation and experimentation, reveals for the first time distinct adsorption behaviors depending on the amino acid sequences: peptides based on valine, tyrosine, or tryptophan form compact, high-affinity coronas, while those based on arginine exhibit weak and dispersed adsorption, with increased solvent exposure. Coronas incorporating valine-based peptides tend to agglomerate, whereas those incorporating arginine-based peptides destabilize at high temperatures.
The computational predictions were experimentally validated on a quantitative level (by measuring equilibrium adsorption isotherms), reinforcing confidence in the protocol and simulations.
These results provide an atomistic understanding of corona formation and establish a mechanical basis for predicting peptide-plastic interactions, which is essential for understanding certain aspects of environmental pollution by nanoplastics and assessing the health and ecosystem risks associated with the interactions of these nanoparticles with living organisms.
Contact Institut des sciences du vivant Frédéric-Joliot
This text was translated with the assistance of Mistral AI.
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[1] Each year, 460 million tons of plastic are produced, and a significant proportion quickly ends up in the oceans, particularly in the form of primary and secondary microplastics (https://www.ecologie.gouv.fr/politiques-publiques/traite-mondial-contre-pollution-plastique). Primary microplastics are directly released into the environment, for example from the washing of synthetic clothing or the abrasion of tires on roads. Secondary microplastics result from the degradation of plastic objects such as bottles and bags. Secondary microplastics account for more than two-thirds of the microplastics found in the ocean. (Source: https://www.europarl.europa.eu/news/fr/headlines/society/20181116STO19217/microplastiques-sources-impact-et-solutions?)
[2] https://www.unep.org/fr/resources/de-la-pollution-la-solution-une-evaluation-mondiale-des-dechets-marins-et-de-la-pollution