Using frequency-domain lifetime spectroscopy and fluorescence lifetime imaging microscopy, we are examining the ability of retinol to probe lipid microenvironments. These measurements allow us to evaluate the positioning of the retinol within the lipid bilayer of vesicles, and determine the corresponding effect on fluorescence properties.
Big picture questions: Is retinol a useful reporter for label-free fluorescence lifetime imaging? Are traditional approaches to retinol stabilization in capsules necessary and sufficient?
We have found that retinol distribution in the bilayer changes with temperature and lipid cholesterol content. While cholesterol has been suggested to improve stability of retinol (and other molecules) in bilayers, we find that this is strongly influenced by the base lipid composition.