Catechol-Functionalized Elastin-like Polypeptides as Tissue Adhesives

Adhesives can potentially be used to achieve fast and efficient wound closure; however, current products show poor bonding on wet surfaces, undergo swelling, and lack adequate biocompatibility. We designed a hydrogel adhesive with recombinant elastin-like polypeptides (ELPs), which are flexible proteins that can be customized for biomedical needs. The adhesive proteins are synthesized by chemically modifying the ELPs with dopamine, which contain adhesive catechol moieties. The resulting catechol-functional ELPs or Cat-ELPs can form flexible hydrogels that show stable swelling in aqueous conditions at 37 °C. We demonstrate their flexibility and viscoelastic properties through rheology. We also show the advantage of using customizable recombinant proteins to improve the material biological properties by demonstrating improved fibroblast binding on Cat-ELP by adding ELP with "RGD" peptides. We further confirmed in vivo biocompatibility and biodegradation of Cat-ELP hydrogels by implanting them in mice and monitoring for 10 weeks. Finally, we tested the bonding strength of the adhesives on porcine skin through tensile pull-off and lap-shear testing, in which we found strengths of 37 and 39 kPa, respectively. We demonstrated the tensile bonding strength by suspending a 2 kg mass on a one square inch (6.5 cm²) skin sample. As our adhesives are developed further, our strategy combining recombinant protein engineering and chemical modification will help yield an ideal bioadhesive for wound closure.