Advantages of a synchrotron light source for fluorescence-detected linear dichroism

Fluorescence-detected linear dichroism (FD-LD) enables one to collect linear dichroism spectra for oriented fluorophores in the presence of other absorbing species and light scattering. The experiment proceeds by scanning the excitation wavelength and using a filter to collect only emitted photons from the fluorophore. Thus, it has the potential to give data with enhanced selectivity and quality. By using a synchrotron radiation light source and fluorescence-detection we show data for a range of fluorophores in different orienting environments. Film and flow-oriented FD-LD spectra were collected down to 170 nm. Even for flow-oriented liposomes we have data collected down to 210 nm. For strongly scattering samples, e.g. liposomes, FD-LD has the clear advantage that scattering is absent for the longer wavelength fluorescence photons. The collimated and smaller beam size of the synchrotron radiation also give rise to sharper and more well-defined features in the spectra. The data here are those presented as figures in a paper submitted to the journal "Chirality" in January 2024. Data units are nm for the wavelength (x-axes) and the units of the LD, FD-LD and fluorescence data are described in detail in the Materials and Methods section of the associated publication. A reference to the data origin file on the Aarhus University servers is found in cell A1 of each sheet.