Manipulation of Mechanical Properties in Protein-Polysaccharide Hydrogels
Mentor 1
Ionel Popa
Start Date
16-4-2021 12:00 AM
Description
The ability to fine-tune the physical structure and mechanical properties of biomaterials is desirable for applications in tissue engineering as well as the design of cell scaffolds and smart materials. The porous and highly absorbent network of hydrogel materials offers an environment similar to the extracellular matrix (ECM), capable of supporting cell growth, while specifically tailored material properties can alter the physical form and mechanical behavior of the substrate. Here, we synthesize protein-based hydrogels using a photoactivated reaction to covalently cross-link bovine serum albumin (BSA). The addition of the polysaccharide, alginate during synthesis allows for the formation of a protein-polysaccharide hydrogel, with a primary network of covalent cross-links between BSA molecules and a secondary network obtained through the ionic interaction of alginate chains with calcium cations. In calcium chloride solution, alginate chains associate with calcium cations to form an insoluble gel within the covalent protein network, significantly increasing the stiffness of the material. When exposed to specific chelating agents, the calcium ions dissociate and the alginate chains revert to their water-soluble form, altering the physical structure of the protein-polysaccharide hydrogel. Characterization of mechanical response through force-clamp rheometry revealed a marked decrease in stiffness and strength as a result of the removal of the secondary network. This method of hydrogel synthesis demonstrates the ability to manipulate mechanical properties based on changes in aqueous environment and explores a controlled mechanism of biomaterial degradation.
Manipulation of Mechanical Properties in Protein-Polysaccharide Hydrogels
The ability to fine-tune the physical structure and mechanical properties of biomaterials is desirable for applications in tissue engineering as well as the design of cell scaffolds and smart materials. The porous and highly absorbent network of hydrogel materials offers an environment similar to the extracellular matrix (ECM), capable of supporting cell growth, while specifically tailored material properties can alter the physical form and mechanical behavior of the substrate. Here, we synthesize protein-based hydrogels using a photoactivated reaction to covalently cross-link bovine serum albumin (BSA). The addition of the polysaccharide, alginate during synthesis allows for the formation of a protein-polysaccharide hydrogel, with a primary network of covalent cross-links between BSA molecules and a secondary network obtained through the ionic interaction of alginate chains with calcium cations. In calcium chloride solution, alginate chains associate with calcium cations to form an insoluble gel within the covalent protein network, significantly increasing the stiffness of the material. When exposed to specific chelating agents, the calcium ions dissociate and the alginate chains revert to their water-soluble form, altering the physical structure of the protein-polysaccharide hydrogel. Characterization of mechanical response through force-clamp rheometry revealed a marked decrease in stiffness and strength as a result of the removal of the secondary network. This method of hydrogel synthesis demonstrates the ability to manipulate mechanical properties based on changes in aqueous environment and explores a controlled mechanism of biomaterial degradation.
