Stabilization of Liposomes by Perfluorinated Compounds

Abstract

Perfluorinated compounds (PFCs) are emerging persistent environmental contaminants that may be toxic to animals and humans. To gain fundamental insights into the mechanism of their toxicity, the interactions of phosphocholine (PC) liposomes as model membranes were studied with three types of PFCs, including perfluorooctanoic acid, perfluorooctane sulfonate, and perfluorohexanesulfonic acid potassium salt, together with three common surfactants: sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and sodium 1-heptanesulfonate (SHS). The interactions were systematically characterized by zeta potential measurement, dynamic light scattering, negative-stain transmission electron microscopy, and fluorescence spectroscopy. Unmodified liposomes, calcein-loaded liposomes, and Laurdan dye-embedded liposomes were all tested. By gradually increasing the temperature, the three PFCs and SHS decreased the leakage of calcein-loaded 1,2-dipalmitoyl-sn-glycero-3-phosphocholine liposomes, whereas SDS and CTAB increased the leakage. The PFCs that affected the lipid membranes stronger than SHS were attributable to their perfluoroalkyl carbon chains. Packing of the lipids was further studied using Laurdan dye as a probe. Calcein leakage tests also indicated that PFCs inhibited lipid membrane leakage induced by inorganic nanoparticles such as silica and gold nanoparticles. This study confirmed the similar effect of the PFCs as cholesterol in affecting membrane properties and would be helpful for understanding the interaction mechanism of PFCs and cell membranes.

Albumin Proteins as Delivery Vehicles for PFAS Contaminants into Respiratory Membranes

“…When directed against the plasma membrane of epithelial cells, this lytic activity could activate damage-associated molecular patterns (DAMPs). These are pro-inflammatory compounds such as interleukin 1α (IL-1α), heat-shock protein 70 (HSP70), and tumor necrosis factor alpha (TNFα) which are released in response to cellular damage or stress. − Damage to epithelial cells through the introduction of membrane-destabilizing agents can induce the upregulation of DAMPs, , which can be correlated with asthma and other inflammatory disorders. − The ability of BSA–PFOA complexes to permeabilize lipid bilayers could induce DAMP release in a similar manner, providing an additional avenue through which exposure to dust particles containing both PFAS and protein contaminants contributes to negative health outcomes among effected populations. − …”

Enzymatic elaboration of oxime-linked glycoconjugates in solution and on liposomes

“…These zeta potentials are comparable to reported values for DMPC liposomes in water and other buffers (−5 to −9 mV). 53,54…”