(192e) Characterization of Modular Resilin-Based Proteins for Application in Cartilage Engineering

Recombinant proteins are a promising scaffold for tissue engineering applications.  Protein-based biomaterials have several advantages over natural and synthetic polymers, including precise control over molecular weight and composition, modular swapping of functional domains, and tunable mechanical properties.

Resilin is an elastomeric protein found in insect cuticles.  It has high strain, fatigue lifetime, and resilience.  Our laboratory has successfully developed a modular recombinant protein that is composed of: 1) resilin repeats that serve as a mechanical domain, 2) a cell-binding sequence that confers bioactivity, and 3) lysine residues that serve as crosslinking sites.  We have successfully expressed our resilin proteins in a fermentation system and obtained a yield of 54.6 mg/L.  The identity and purity of our protein were confirmed by SDS-PAGE, Western blot, mass spectrometry, and amino acid analysis.  Our results demonstrated that the compressive modulus of the crosslinked resilin protein is 2.4 MPa, which is similar to the compressive modulus of natural cartilage.  Further studies will examine the range of mechanical properties that can be achieved by varying the crosslinking density.  We also cultured human mesenchymal stem cells on the resilin-based proteins.  Our results demonstrated that the resilin-based proteins are cytocompatible and that the cells can recognize the cell-binding domain in a sequence-specific manner.  These results demonstrate that our protein-based biomaterials are promising candidates for regenerative cartilage engineering.