Supervision: Thierry Charitat, André Schroder and Carlos Marques
Our contribution to research in the area of lipid oxidation in eukariotic cells is based on the central intuition that progress can only be achieved in new biomimetic membrane systems where the spatial localization of the oxidation events might be controlled and monitored. Accordingly, we have developed new photosensitizer agents that can be anchored in Giant Unilamelar Vesicles (GUVs). It is important to stress that progress in the control of the spatial distri- bution of oxidation allows for a selection of the oxidation pathways, as we show in this study for the particular case of hydroperoxidation, and therefore constrains anti-oxidant strategies. In association with new tools for the quantification of the oxidation events, these new models have provided a complete scenario for the hydroperoxidation mechanisms, from the production of the oxidant species (1O2) to the final chemical and physical modifications induced on the self-assembled bilayers. We report that GUVs are able to survive full hydroperoxidation, showing that membrane integrity can be preserved under these oxidation conditions. Our experimental setup allows to measure the relative area increase produced upon peroxidation, the associated change in mechanical properties of the membrane and also the hydroperoxidation efficiency, all of them with good precisions. Further insights into the molecular modifications under oxidation have been studied at the air-water interface, using lipid monolayers.