Abstract
Recent work has established that Laurdan, one of the most widely used probes in membrane biophysics, can adopt two distinct conformations whose populations can be biased by angle–dependent polarized excitation. Existing approaches use band–integrated detection that cannot resolve the wavelength dependence of conformer–attributable spectral changes. Here, we apply wavelength–resolved decay–associated spectroscopy to Laurdan in DOPC and DPPC supported lipid bilayers as a function of tilt angle. DOPC shows distinct angle–dependent spectral features, most notably a bimodal–to–monomodal transition in the short–lifetime amplitude spectrum inaccessible to band–integrated measurements; DPPC shows no resolvable angular dependence, consistent with low gel–phase prevalence of the bent conformer.
