(442g) Hydrophobicity and Functionality-Dependent Interactions of Poly- and Perfluoroalkyl Substances (PFAS) on Model Biological Membranes

Poly- and Perfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants and used for various commercial applications. They have been found to accumulate with eukaryotic cell membranes and alter membrane properties. Detailed fundamental understanding of the interaction in the bulk membrane still remains to be explored. In this report, two synthetic phospholipid membranes (1,2-dimyristoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)) were created and exposed to a variety of PFAS with different chain lengths and head groups functionality. Considering two different phospholipid membrane types with different degrees of saturation and different phase behavior (L_β, and L_d phases), a more comprehensive examination of PFAS effect on size, surface charge (zeta potential), and membrane fluidity were investigated. All the PFASs were found to interact with the bilayer by incorporation, effecting the membrane properties (condensation and/or fluidization), indicating PFAS ability to accumulate once ingested or taken up by organisms. Complementary to these results, PAFSs were also found to alter the gel-fluid phase transition temperature of DPPC bilayers, demonstrating that PFAS affected lateral phospholipid interaction. The hydrophobicity of PFAS correlated with the chain length (except PFOA), was also found to strongly influence the interactions. The quantitative estimation of the partition coefficient of PFAS from LC-MS study corroborated the interaction of PFAS with membranes also dependent on the hydrophobicity, head group functionality, and the membrane types. This work provides a framework for investigating how PFAS chain length and head group functionality effect on the physicochemical properties of synthetic membrane types at a varying range of [lipid] to [PFAS] ratio.