Hydrogels have been widely used in scientific research and medical field. The emerging studies on hydrogel materials are focused on new approaches that enable precise control over the dynamic properties. Here we designed two types of entirely recombinant protein-based hydrogels based on metal ion-protein coordination and the reconstitution of split green fluorescent protein (GFP) fragments, respectively.

In order to use metal ions to facilitate protein self-assembly and gelation, we designed and constructed a doubly His6-tagged elastin-like polypeptide using standard recombinant DNA technology. The resulting proteins were able to form hydrogels with varied mechanical properties in the presence of divalent metal ions such as Cu (II) and Ni (II). We speculate that the system will have tu...[ Read more ]

Hydrogels have been widely used in scientific research and medical field. The emerging studies on hydrogel materials are focused on new approaches that enable precise control over the dynamic properties. Here we designed two types of entirely recombinant protein-based hydrogels based on metal ion-protein coordination and the reconstitution of split green fluorescent protein (GFP) fragments, respectively.

In order to use metal ions to facilitate protein self-assembly and gelation, we designed and constructed a doubly His6-tagged elastin-like polypeptide using standard recombinant DNA technology. The resulting proteins were able to form hydrogels with varied mechanical properties in the presence of divalent metal ions such as Cu (II) and Ni (II). We speculate that the system will have tunable mechanical properties by varying the type and concentrations of ions, and that the metal-templated gelation system is also amenable to further functionalization by other His6-tagged recombinant proteins.

Despite great potential in studying biomolecular interactions and biological signaling in vitro and in vivo, reconstitution of split GFP fragments has rarely been considered for designing new materials for biomedical applications. We designed a two-component protein gelation system based on the reconstitution of the two GFP fragments, GFP11 and GFP1-10, corresponding to the dissected β-strand 11 and the remaining part of the protein. We were able covalently polymerize the split GFP halves using genetically encoded Spy chemistry. The resulting protein hydrogels exhibited green fluorescence, indicating the successful reconstitution of GFPs under gelation conditions. Given the sensitivity of GFP fluorescence to mechanical stress, this split GFP-based hydrogel system may provide a new platform for biologists to study mechanobiology.