Nordic Workshop on Scattering from Soft Matter

The Interaction of Perfluoroalkyl Substances with Mineral Surfaces and Biological Membranes

18 Jan 2018, 09:20

20m

Auditorium (Medicon Village)

Session 3

Speaker

Ms Shirin Nouhi (Uppsala University)

Description

Perfluoroalkyl substances (PFASs) have hydrophobic and hydrophilic characteristics which makes them useful in many commercial and industrial applications such as textile, leather and paper impregnation, detergents, fire-fighting foam, etc. These compounds are receiving increasing global concern due to their persistence, bioaccumulation and possible adverse effects on the environment and living organisms [1]. In this project, we have investigated the interaction of PFASs with biological and mineral model system interfaces using neutron reflection. The PFAS were selected to allow comparing the effect of hydrophobic chain length and hydrophilic functional group on their interactions with the interface. The adsorption of PFASs was studied at two types of mineral surfaces (Al2O3, positively charged and SiO2, negatively charged). The electrostatic interaction was shown to be the driving force in the sorption process. The adsorbed PFAS could be removed by gentle rinsing with water. The adsorption process was shown to be influenced directly by the solubility limit of the PFAS which changes with the chain length [2]. Phospholipids are the building blocks of cell membranes and are commonly used as a model system to understand the fundamental behavior of biological membranes. DMPC (1,2-Dimyristoyl-sn-glycero-3-phosphocholine) bilayer was chosen as the model interface in this study. PFASs have shown to penetrate into the bilayer and displace lipids to accommodate themselves. Off-specular data from bilayers which have been immersed to PFASs indicate rough and patchy structures. Extensive rinsing with water can remove some PFAS, but a less dense bilayer is left behind. The interaction of these PFAS was shown to vary with both head group and chain length, and strongly correlate with the PFAS solubility limit [3]. 1. Hellsing et al. Chemosphere 159 (2016) 385e391. 2. Ahrens et al, Chemosphere 129 (2015) 33–38. 3. Nouhi et al, Journal of Colloid and Interface Science 155 (2018) 474-481.