Mechanical stability of lipid monolayers and bilayers in the presence of pollutants

The environmental threat of plastic pollution is becoming increasingly important, with millions of tons of plastic debris being dumped into aquatic ecosystems each year. As a result, tiny fragments of plastic, called microplastics (particles < 5 mm, including nanosized plastics < 1 µm), are now found everywhere: freshwater, oceans and beaches, seabeds, rain, air and even in areas such as deserts and mountains. The small size of these plastics makes them particularly dangerous and ingestible by aquatic biota or directly by humans. Even more alarming, poly- and perfluoroalkyl substances (PFAS) coined forever chemicals, which have been found to pose a serious human health risk and linked to cancer, are omnipresent and persistent over long time scales in the environment, where they are in contact with microplastics.

However, despite recent efforts to investigate the role of commercial beads with some pollutants on bilayers (the main component of cell membrane) the effect of PFAS and/or microplastics with complex shapes, sizes and chemical compositions on living systems is still not fully understood. To address this gap, we propose to investigate how varying proportions of real microplastics and/or PFOA/PFOS affect the dynamics and the stability of lipid monolayers and bilayers (DPhPC).

We will first quantify monolayers dynamics at a water-hexadecane interface with measurements of surface tension, using the pendant drop method. We will then characterize droplet interface bilayers (DIB), where the bilayer is formed between two drops, to study the mechanical response of bilayers in the presence of pollutants. Altogether, this work aims to advance our understanding of the role of pollution on lipid membranes, in an effort to illuminate possible fundamental causes of pollution-related damage to cells and guide future avenues of remediation research.