Covalently crosslinked mussel byssus protein-based materials with tunable properties

Abstract

Mussels’ anchoring threads, named byssus, are collagen-rich fibers with outstanding mechanical properties. Our previous work has shown the possibility of producing a byssus protein hydrolyzate with good film-forming ability, providing a promising new avenue for the preparation of biomaterials. Materials prepared from regenerated fibrous proteins often need additional treatments to reach the performance required for targeted applications. Here, we studied the effect of covalent crosslinking, using a carbodiimide or glutaraldehyde, on the mechanical properties and enzymatic resistance of byssus-based materials. The results show that the mechanical properties of the films can be tuned, and that a higher crosslinking degree leads to increases in modulus and strength accompanied by a loss of extensibility. Structural analysis performed by infrared spectroscopy revealed that crosslinking induces an unexpected transition from aggregated strands to hydrated collagen/PPII-related helical structures. The materials were nevertheless more resistant to collagenase degradation as a result of higher crosslinking density. This new set of materials prepared in aqueous environment could find a niche in tissue engineering.