Liposome biodistribution by time resolved fluorimetry of lipophilic europium complexes.

The use of conventional fluorophores suffers from some limitations in biological fluids due to low signal/background ratio. Today, this sensitivity issue might be reasonably improved thanks to lanthanide chelates, by selective detection of long decay fluorescence. Use of pulsed light source time-resolved fluorimetry takes into account the fluorescence decay time of the lanthanide chelates to gain sensitivity in biological media. Lipid-DTPA: Eu compounds have been prepared and incorporated into liposomes to evaluate europium based detection of liposomes in biological media. Fluorescence emission was not modified by this incorporation. Europium labelled liposomes were used for biodistribution studies and showed their use in this context.