Selective removal of heavy metals by engineered vesicles: A simplified model for uptake kinetics

A simplified mathematical model is presented to describe the kinetic behaviour of lipid vesicles designed to remove metal ions from dilute solutions. The vescicles contain a selective ionophore in the lipid bilayer and a chelating agent in the aqueous core. The model accounts for the facilitated diffusion of the metal species across the membrane and for the formation of the complex with the chelator. With the analytical relationships developed it was possible to emphasize the combined effect provided by the presence of the selective carrier and the chelating agent. The model can be used to predict the maximum loading capacity of a vesicle and provides useful directions for the optimization of the molecular behaviour of these microscopic devices.