Spectroscopic investigation of fluorinated phenols as pH-sensitive probes in mixed liposomal systems?

RSC Advances Pub Date: 2014-04-04 DOI: 10.1039/C4RA01507J

Abstract

The pKa values of three fluorinated phenols, 2,4,6-trifluorophenol (3FP), 2,3,5,6-tetrafluorophenol (4FP) and 2,3,4,5,6-pentafluorophenol (5FP) have been measured by using UV-vis and 19F-NMR spectroscopy at 25 °C in water and in the presence of pure POPC, pure DDAB and mixed POPC–DDAB liposomes. The probe–liposome interaction depends on both the equilibrium between the neutral and ionic forms of 3FP, 4FP and 5FP and the charge on the liposomal surface determined by zeta potential measurements in a wide pH range. The data from the two spectroscopic techniques are in good agreement and show that the incorporation of DDAB into the POPC membrane decreases the pKa values of the probes with a non-linear correlation.

Graphical abstract: Spectroscopic investigation of fluorinated phenols as pH-sensitive probes in mixed liposomal systems
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