Temperature-regulated Hybrid Protein Hydrogel for Recyclable Extraction of Uranium from Seawater

To extend the temperature-controlled biohydrogel system from peptides to proteins, we synthesized a protein hydrogel by integrating super uranyl binding protein (SUP) and N-isopropylacrylamide (NIPAM). The protein hydrogel adsorbs trace uranyl from seawater and releases it only by separate temperature regulation. We explored the mechanism of the hybrid hydrogel to regulate SUP activity by comparing different immobilized sites and analyzing viscoelastic effectiveness. Stretching amino acid residues near the uranyl binding site plays a key role in regulation, and the volume variation of the hybrid hydrogel across the low critical solution temperature provides sufficient driving force to deform the SUP. This work demonstrates the prospective potential of using other proteins in hydrogel systems for functional regulation.