The effects of lanthanide ions and their complexes of citrate and DTPA ligandson the fluldity of dipathetoylphosphatidylethanolamine (DPPE) bilayers have been studiedby FT-Raman spectroscopy. The results show that lanthanide ions oflower concentrationndecrease the nuldity of acyl chains of DPPE bilayers and change the conformation of c C-C backbone from gauche to the trans lanthanide ions of higher concentration, however,increase the fluldity of acyl chains and increase the gauche population of C-C-C backbone.Lanthainde complex of citrate have no effect on the fluidity of acyl chains of DPPE bilayersin the region of experdriental concentration, but La-DTPA complex increase slightly thefluidity of acyl chains. The results also indicated that lanthainde ion of lower concentrationchanged the lattice packing of hydrocarbon chains from hexagonal form to orthorhombicform, but it is still in hexagonal or distorted hexagonal lattice cell in the gel state in thepresence of metaJ ions and lanthanide complexes of higher
