AbstractUnilamellar phosphatidylcholine vesicles, harboring the ionophore, A23187, in the bilayer and the water‐soluble chelating agent, nitrilotriacetate, in the vesicle interior, rapidly sequester and concentrate Cd2+from dilute aqueous solution. Metal‐sorbing vesicle permeabilities for cadmium ion at 5 ppm (42.8 μM) ranged from 8.09 × 10−7to 1.27 × 10−4cm/s for surface A23187 concentrations of 0.22–2.27 pmol/cm2(which correspond to lipid: carrier molar ratios of 2000:1 to 200:1) and pH's from 5.5 to 8.5. The Cd2+permeability shows linear variation with carrier concentration under the conditions studied. As pH is decreased, an increasing fraction of the A23187 becomes protonated, and the permeability exhibits a positive linear relationship with a function related to that for the fraction of unprotonated carrier. These noncovalently assembled, metal‐sorbing vesicles exhibit shelf lives of several months and remain stable throughout typical metal so
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