Analysis of interactions between cinnamycin and biomimetic membranes

The interaction between the cinnamycin and the biomimetic membranes was studied using the atomic force microscope(AFM). The bilayer was composed of the monolayer tethered on the gold surface and the outer layer fused with the vesicles on the monolayer. The vesicles were prepared at the desired ratio of dioleoylphosphatidylethanolamine(DOPE) to dioleoylphosphatidylcholine(DOPC). On the bilayer, the surface force measurement was performed with the cinnamycin immobilized covalently on the tip surface. The immobilization led to the presence of the adhesion, which was found while the tip was retracted from the bilayer. In addition, the magnitude of the adhesive force was changed with respect to the composition of DOPE in the outer layer. The difference in the adhesion may be attributed to the mean-molecular-area of DOPE and the specific-binding density on the outer layer. Furthermore, the analysis of the rupture force with respect to the loading rate indicated that the rupture length was around 0.1∼0.13 nm, which was similar to that of a van der Waals bond.