A Peptoid-Based Combinatorial and Computational Approach to Developing Ligands for Uranyl Sequestration from Seawater

The selective binding of uranyl for extraction from seawater by using polymer sorbents holds promise as a sustainable source of uranium for nuclear energy. A combinatorially synthesized peptoid library (N-substituted glycine oligomers) was screened for uranyl binding with the goal of identifying high-affinity ligands for use in polymer sorbents. Qualitative screening techniques using a dye, arsenazo III, identified three uranyl-binding sequences, all of which contained only carboxylic acids as the active binding groups. Fluorescence spectroscopy was used to determine a dissociation constant for one of the identified peptoids by monitoring the decrease in peptoid fluorescence upon uranyl binding. Density functional theory calculations were used to model the solution-state binding of these sequences to understand favored binding modes and geometries.