Periodic Reporting for period 1 - METABOLISM (MEchanical sTABility Of phosphoLIpids bilayerS in the presence of Microplastics)
Periodo di rendicontazione: 2023-06-01 al 2025-05-31
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.
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.
During the reporting period, the project has made substantial progress, culminating in two submitted scientific publications that address core project objectives.
A primary achievement has been the development of a unified theoretical framework that accurately describes the dynamics of irreversible particle adsorption at fluid interfaces. This work, detailed in the preprint "Dynamics of Irreversible Particle Adsorption to Fluid Interfaces," introduces a novel Diffusion-Random Sequential Adsorption (RSA) model. This model successfully captures the complete adsorption process, from the initial diffusion-dominated phase to the later kinetic-limited regime governed by particle crowding—a significant advance over classical equilibrium-based models like the Ward-Tordai framework, which fail to describe such systems accurately. This is a fundamental work that can be apply to understand microplastics adsorption at fluid interfaces.
A second major achievement involved developing a robust and reproducible method to synthesize environmentally relevant polyethylene (PE) nanoplastics. As detailed in the manuscript "Colloidal stability and aggregation of polyethylene (PE) nanoplastics under environmental stressors," this work produced surfactant-free, monodispersed PE nanoparticles (200 nm), providing a realistic model system that is critically needed for environmental and toxicological studies, as commercially available particles are often poor mimics of environmental plastics. This research systematically investigated how environmental stressors, such as UV weathering and the adsorption of PFOA, fundamentally alter the colloidal stability of these nanoplastics, revealing complex stabilization and aggregation mechanisms.
A primary achievement has been the development of a unified theoretical framework that accurately describes the dynamics of irreversible particle adsorption at fluid interfaces. This work, detailed in the preprint "Dynamics of Irreversible Particle Adsorption to Fluid Interfaces," introduces a novel Diffusion-Random Sequential Adsorption (RSA) model. This model successfully captures the complete adsorption process, from the initial diffusion-dominated phase to the later kinetic-limited regime governed by particle crowding—a significant advance over classical equilibrium-based models like the Ward-Tordai framework, which fail to describe such systems accurately. This is a fundamental work that can be apply to understand microplastics adsorption at fluid interfaces.
A second major achievement involved developing a robust and reproducible method to synthesize environmentally relevant polyethylene (PE) nanoplastics. As detailed in the manuscript "Colloidal stability and aggregation of polyethylene (PE) nanoplastics under environmental stressors," this work produced surfactant-free, monodispersed PE nanoparticles (200 nm), providing a realistic model system that is critically needed for environmental and toxicological studies, as commercially available particles are often poor mimics of environmental plastics. This research systematically investigated how environmental stressors, such as UV weathering and the adsorption of PFOA, fundamentally alter the colloidal stability of these nanoplastics, revealing complex stabilization and aggregation mechanisms.
The METABOLISM project has produced results that significantly advance the state of the art in both colloid science and environmental science.
The developed Diffusion-RSA theoretical framework provides a new, powerful predictive tool for understanding and designing systems involving particle-laden interfaces. By successfully modeling irreversible adsorption and steric blocking, it offers a more realistic paradigm for processes crucial to emulsion stabilization, functional material assembly, and the environmental fate of particulate matter and microplastics.
Furthermore, the research on PE nanoplastic stability has unveiled complex interaction mechanisms that challenge and refine existing colloidal theories. Key findings include the role of heterogeneous surface charge in stabilizing pristine particles, the unexpected steric stabilization imparted by adsorbed PFOA (particularly in high-salinity environments), and the induction of irreversible aggregation by UV weathering due to radical formation. This nuanced understanding of nanoplastic behavior is a critical step beyond simplified models and provides a foundational basis for more accurate environmental risk assessments. These findings directly inform predictions about the persistence, transport, and bioavailability of nanoplastics and their co-contaminants in aquatic systems.
The developed Diffusion-RSA theoretical framework provides a new, powerful predictive tool for understanding and designing systems involving particle-laden interfaces. By successfully modeling irreversible adsorption and steric blocking, it offers a more realistic paradigm for processes crucial to emulsion stabilization, functional material assembly, and the environmental fate of particulate matter and microplastics.
Furthermore, the research on PE nanoplastic stability has unveiled complex interaction mechanisms that challenge and refine existing colloidal theories. Key findings include the role of heterogeneous surface charge in stabilizing pristine particles, the unexpected steric stabilization imparted by adsorbed PFOA (particularly in high-salinity environments), and the induction of irreversible aggregation by UV weathering due to radical formation. This nuanced understanding of nanoplastic behavior is a critical step beyond simplified models and provides a foundational basis for more accurate environmental risk assessments. These findings directly inform predictions about the persistence, transport, and bioavailability of nanoplastics and their co-contaminants in aquatic systems.