Fluorinated/Hydrogenated Mixed Vesicles as Carrier of Model Biomolecules: A Spectroscopic Study

Light scattering (LS), small-angle neutron scattering (SANS), electron spin resonance (ESR), and electronic spectroscopy in the UV−vis region were used to characterize hydrogenated/fluorinated mixed vesicles to be used as carriers for molecules of biological and pharmaceutical interest. n -Dodecylbetaine and the ammonium salt of a perfluoropolyether carboxylate are known to spontaneously give mixed stable vesicles. Because of its heme-like structure, an octakis(octylthio)tetraazaporphyrin, under the form of the free base and of its Cu(II) metal complex, was utilized as a model cargo to penetrate into the vesicles. The porphyrins appreciably aggregated, as indicated by their electronic spectra, without disturbing the bilayer dynamics and polarity as revealed by ESR data using nitroxide probes located in different regions of the vesicle's membrane. Light scattering data showed, conversely, a significant contraction of the vesicle's radius, which is in agreement with the increased curvature expected from the insertion of polyazamacrocycles in the bilayer membrane.