Kinetic and thermodynamic studies of cinnamycin specific-adsorption on PE-Included-Membranes using surface plasmon resonance

•Specific adsorption of cinnamycin on DOPE-included-biomimetic membranes.•Coverage fraction converted from the ratio of binding to saturated response.•Kinetic and thermodynamic estimation based on the coverage fraction.•Rate constant of the adsorption at 6∼7 × 10−3 s-1.•Equilibrium constant of the adsorption between 1 × 107 and 5 × 107 M−1. The binding of the cinnamycin on the biomimetic membrane was studied with respect to time using the surface plasmon resonance(SPR). The membrane was composed of the inner layer tethered on the gold surface and the outer layer formed on the inner layer, which was at the desired ratio of dioleoylphosphatidylethanolamine(DOPE) to dioleoylphosphatidyl- choline(DOPC). On the bilayer, the cinnamycin solution was injected and showed different behavior of the binding with respect to time up on its concentration. For kinetic analysis, the behavior was converted to the coverage fraction with respect to time, which was ratio to the saturated response of 5 μM cinnamycin solution. The fraction change with respect to time was function of the available-site, which was eventually the subtraction of the fraction from one. With the fitting of the first order of the available site, the rate constant was acquired into 6∼7 × 10−3 s-1. Furthermore, the reciprocals of the fraction and the concentration were fitted with the Langmuir adsorption isotherm. From the fitting, the equilibrium constant was between 1 × 107 and 5 × 107 M-1.