Modulating the Viscoelastic Properties of Covalently Crosslinked Protein Hydrogels

Protein engineering allows for the programming of specific building blocks to form functional and novel materials with customisable physical properties suitable for tailored engineering applications. We have successfully designed and programmed engineered proteins to form covalent molecular networks with defined physical characteristics. Our hydrogel design incorporates the SpyTag (ST) peptide and SpyCatcher (SC) protein that spontaneously form covalent crosslinks upon mixing. This genetically encodable chemistry allowed us to easily incorporate two stiff and rod-like recombinant proteins in the hydrogels and modulate the resulting viscoelastic properties. We demonstrated how differences in the composition of the microscopic building blocks change the macroscopic viscoelastic properties of the hydrogels. We specifically investigated how the identity of the protein pairs, the molar ratio of ST:SC, and the concentration of the proteins influence the viscoelastic response of the hydrogels. By showing tuneable changes in protein hydrogel rheology, we increased the capabilities of synthetic biology to create novel materials, allowing engineering biology to interface with soft matter, tissue engineering, and material science.

Automated summary

Protein engineering allows for the creation of customized materials with specific physical properties suitable for engineering applications. We successfully designed and programmed engineered proteins to form covalent molecular networks in hydrogels, demonstrating the ability to modulate their viscoelastic properties. By investigating the composition of the building blocks, protein identity, and concentration, we showed how these variables influence the viscoelastic response of the hydrogels. These findings enhance the capabilities of synthetic biology in creating novel materials and enabling the interface between biological engineering and material science.