Thermal Responsive Ion Selectivity of Uranyl Peroxide Nanocages: An Inorganic Mimic of K + Ion Channels

An actinyl peroxide cage cluster, Li 48+ m K 12 (OH) m [UO 2 (O 2 )(OH)] 60 (H 2 O) n ( m ≈20 and n ≈310; U 60 ), discriminates precisely between Na + and K + ions when heated to certain temperatures, a most essential feature for K + selective filters. The U 60 clusters demonstrate several other features in common with K + ion channels, including passive transport of K + ions, a high flux rate, and the dehydration of U 60 and K + ions. These qualities make U 60 (a pure inorganic cluster) a promising ion channel mimic in an aqueous environment. Laser light scattering (LLS) and isothermal titration calorimetry (ITC) studies revealed that the tailorable ion selectivity of U 60 clusters is a result of the thermal responsiveness of the U 60 hydration shells.