MEchanical sTABility Of phosphoLIpids bilayerS in the presence of Microplastics

Project Information

METABOLISM

Grant agreement ID: 101104426

DOI

10.3030/101104426

Project terminated on 27 October 2025

EC signature date 17 April 2023

Start date 1 June 2023

End date 31 May 2026

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 261 380,64

Coordinated by

FUNDACION BIOFISICA BIZKAIA / BIOFISIKA BIZKAIA FUNDAZIOA
Spain

Periodic Reporting for period 2 - METABOLISM (MEchanical sTABility Of phosphoLIpids bilayerS in the presence of Microplastics)

Reporting period: 2025-06-01 to 2026-05-31

Summary of the context and overall objectives of the project

The proliferation of microplastics and per- and polyfluoroalkyl substances (PFAS), known as "forever chemicals," represents a pressing global environmental and health crisis. These persistent pollutants are now ubiquitous, found in everything from drinking water and food to human blood and organs, with PFAS linked to significant health risks, including cancer. Microplastics can act as vectors for other contaminants like PFAS, exacerbating their environmental impact. However, a fundamental understanding of how these pollutants, with their complex sizes, and chemical compositions, interact with living systems at the cellular level is critically lacking.

The METABOLISM project addresses this knowledge gap by aiming to adapt and develop advanced physicochemical and biophysical techniques to understand the adsorption, attachment, and mechanical disruption of fluid interfaces and lipid bilayers—which mimic cell membranes—in the presence of these contaminants. The project's central objective is to create an integrated platform to simultaneously image and measure interfacial changes, thereby quantifying the dysfunction induced by pollutants. By investigating these interactions, METABOLISM seeks to provide crucial new knowledge on the health impacts of micro- and nanoplastic pollution and highlight the urgent need for improved remediation strategies.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During the reporting period, the project has made substantial progress, culminating in two submitted scientific publications that address core project objectives.

A primary achievement was the development and experimental validation of a unified framework describing the dynamics of irreversible particle adsorption at fluid interfaces. The article “Dynamics of Irreversible Particle Adsorption to Fluid Interfaces” introduces a Diffusion–Random Sequential Adsorption model that couples particle transport from the bulk with an interfacial kinetic condition accounting for irreversible attachment and progressive steric blocking as the interface becomes crowded. Using complementary microtensiometry and pendant-drop tensiometry experiments, the framework successfully describes the transition from an initially diffusion-limited regime to a later kinetically limited regime. A dynamic Thiele modulus was also introduced to quantify the relative contributions of diffusion and interfacial adsorption kinetics. This represents an important advance over classical models such as the Ward–Tordai framework, which assumes local dynamic equilibrium and cannot capture the coverage-dependent kinetic slowdown associated with irreversible particle adsorption. Although validated using model colloidal particles, the framework is broadly relevant to particle-laden interfaces and provides a foundation for future studies of micro- and nanoplastic adsorption at environmental and biological interfaces.

A second major achievement was the development of a reproducible nanoprecipitation method for producing spherical, surfactant-free polyethylene nanoplastics with an average diameter of approximately 200 nm and a relatively narrow particle-size distribution. These particles provide an environmentally relevant model system because polyethylene is one of the most prevalent plastics in the environment, while well-defined polyethylene nanoparticles are not commercially available and commonly used model particles often contain surfactants or stabilizing ligands. The study “Colloidal Stability and Aggregation of Polyethylene (PE) Nanoplastics under UV Weathering and PFOA Contamination” systematically quantified how salinity, accelerated UV weathering and exposure to perfluorooctanoic acid affect particle aggregation and surface properties. Pristine particles retained some colloidal stability at low salt concentrations, most likely because of heterogeneous surface charges resulting from ion adsorption, but aggregated rapidly at higher salinity. PFOA had little effect at low salt concentrations and produced only modest additional stabilization at higher salinity. In contrast, UV weathering strongly promoted aggregation, most likely through the formation of reactive surface radicals that increased interparticle adhesion. These findings demonstrate that photochemical ageing and co-contaminant adsorption can affect polyethylene nanoplastic stability through distinct mechanisms, providing new insight into their environmental transport and fate.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The METABOLISM project produced results that advance the state of the art in colloid science and environmental nanoplastic research.

The Diffusion–Random Sequential Adsorption framework provides a more realistic description of irreversible particle adsorption at fluid interfaces by accounting for both bulk diffusion and progressive steric blocking. Unlike classical equilibrium-based models, it captures the transition from diffusion-controlled to kinetically controlled adsorption and offers a predictive tool for the study and design of particle-laden interfaces. Its potential applications include emulsion stabilization, functional material assembly and future investigations of micro- and nanoplastic behaviour at environmental and biological interfaces.

The work on surfactant-free polyethylene nanoplastics also showed that their colloidal stability cannot be predicted from classical theories or surface charge alone. PFOA adsorption provided additional stabilization, particularly at elevated salinity, whereas UV weathering promoted aggregation through increased interparticle adhesion associated with radical formation. These results improve understanding of how ageing and co-contaminants can modify nanoplastic persistence and transport in aquatic environments. Further uptake will require validation with environmentally derived plastics, more complex water compositions and biological interfaces, as well as improved models incorporating cooperative particle interactions and interfacial clustering.