FITC-labeled lipopolysaccharide: use as a probe for liposomal membrane incorporation studies

Abstract

FITC‐labeled LPS from Neisseria meningitidis can be used as a probe to follow the process of LPS incorporation into liposomal membrane and to study its interaction with a bilayer. The incorporation of FITC‐LPS into the bilayer was proved by physicochemical methods as well as by liposomal LPS toxirity decrease in actinomycin D‐sensitized mice. Fluorescence intensity increase was observed upon the insertion of FITC‐LPS into the membrane of dehydration/rehydration vesicles and vesicles obtained by co‐sonication of lipid suspension and FITC‐LPS. Following FITC‐LPS fluorescence polarization it was shown that the substance seems to be clusterized m the liposomal membrane starting from FITC‐LPS/lipid molar ratio 1:800.