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

ABSTRACT

An actinyl peroxide cage cluster, Li48+m K12 (OH)m [UO2 (O2 )(OH)]60 (H2 O)n (m≈20 and n≈310; U60 ), discriminates precisely between Na(+) and K(+) ions when heated to certain temperatures, a most essential feature for K(+) selective filters. The U60 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 U60 and K(+) ions. These qualities make U60 (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 U60 clusters is a result of the thermal responsiveness of the U60 hydration shells.