Modification and crosslinking of gelatin-based biomaterials as tissue adhesives

Tissue adhesives have been developed to overcome the difficulties of conventional wound closure techniques (e.g. sutures and staples), such as the potential for collateral damage and difficulty of stopping body fluid and gas. At the same time, it provides advantages such as simpler implementation, less painful, and does not require removal. However, representative adhesives such as cyanoacrylates and fibrin glues are plagued by cytotoxicity and low adhesion. In this study, we choose instead gelatin as the backbone of adhesive, due to its biocompatibility, biodegradability, and low cost. Firstly, catechol-modified gelatin and phenol-modified gelatin were synthesized via an EDC/NHS chemistry. Then, gelatin-based adhesives were prepared via ruthenium-based photochemistry, including photo-crosslinked gelatin (PG), phenol-modified gelatin (PPG), and catechol-modified gelatin (PCG). We also compared the photo-crosslinked adhesives to the recently reported ion-crosslinked catechol-modified gelatin. Our results indicate that gelatin-based adhesives demonstrate lower swelling index, great degradability, and low cytotoxicity. This shows that gelatin-based adhesives demonstrate great potential for wound closure and healing.