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

Abstract

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.

Diffusion-Limited Processes in Hydrogels with Chosen Applications from Drug Delivery to Electronic Components

“…A direct introduction of the isocyanate group by photoinduced copolymerization of 2-isocyanate ethyl methacrylate (ICEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) allows an easy functionalization with bioactive ligands to enable ligand-directed protein immobilization [86]. Highly selective protein-based hydrogels are great for controlled scavenging and release of selected substances, such as UO 2 2+ , where the hydrogel thermal stretching induces uranyl binding protein to lose conformation, favorable for uranyl [87].…”

Enhanced uranium extraction from seawater: from the viewpoint of kinetics and thermodynamics

“…83 Recent advances in protein engineering have revived interest in designing biological systems for selective uranium identification. 92,93 It is possible to affordably attain the needed affinity and high selectivity using biological systems that are capable of self-regeneration. Over billions of years, nature has developed methods to differentiate between useful and harmful metal ions with remarkable sensitivity and selectivity.…”

Uranium extraction from seawater: material design, emerging technologies and marine engineering

“…Thanks to advances in protein engineering, renewed interests have emerged over the past decade in the engineering of biological systems including peptides and proteins with intriguing properties for selective recognition of uranium from seawater. 141,142,[178][179][180][181][182][183][184] For this concept, Zhou et al developed a computational program named URANTEIN to screen proteins with potential binding affinity for UO 2 2+ in the Protein Data Bank (PDB). 178 After the initial screening, more than 5000 hits were identified.…”

“…In this sense, a strategy to integrate SUP proteins with high selectivity into high-order molecular architectures offers a plausible solution to this challenge. 184 Benefiting from the concept of covalent protein assembly tools such as genetically encoded click chemistry (GECC) and genetically encoded SpyTag-SpyCatcher chemistry, 182,185,186 Sun and co-workers demonstrated the feasibility of covalently stitching SUPs into hydrogel materials 181,187 and protein nanofilms 188 capable of selective metal ion sequestration. Specifically, SUP proteins were integrated into macroscopic hydrogel materials through the ''click chemistry'' of thiol-maleimide, and droplets of SUP hydrogels were subsequently processed and cured into monodisperse SUP microbeads with a uniform radius of 165 mm via microfluidic technologies.…”

“…Thanks to advances in protein engineering, renewed interests have emerged over the past decade in the engineering of biological systems including peptides and proteins with intriguing properties for selective recognition of uranium from seawater. 141,142,178–184…”