We have discovered in our recent work on BUs conjugated with bile acid residues that their transport activity was drastically impacted by an increased cholesterol content in the membrane. Therefore, we were curious whether the anion transport by the fluorinated BUs investigated in this work would be impacted as well. We have thus tested the Cl -/HCO3 -antiport activities of all BUs using the lucigenin assay with BUs preincorporated at 0.02 mol% inside the membrane of LUV composed of POPC and cholesterol in a molar ratio of 7:3 (Figure and). Strikingly, the presence of cholesterol in the membrane has a drastic negative impact on the anion transport by particular compounds, while other derivatives remain unaffected or are only slightly affected (Figure , right panel).