Tannin-bearing hydrogel adhesives with enhanced mechanical and adhesion strength in response to protein leakage

Anastomotic leaks are among the most severe side effects following abdominal surgeries. Conventional surgical sealants and emerging hydrogel adhesives often lose mechanical and adhesion strength when exposed to leaked digestive enzymes. Here, we report a tannin-encapsulating tough hydrogel adhesive that exhibits enhanced mechanical and adhesive properties upon the encounter of leaked proteins. The hydrogel is composed of a gelatin-acrylate crosslinked network with encapsulated tannin and can adhere to a wet surface <i>via</i> amine-carboxyl chemistry. In the context of anastomotic leaks, tannin within the hydrogel can form a complex with proteins including the digestive enzymes, leading to increased gel stiffness and storage modulus. The enhanced mechanical strength confers improved adhesive properties on the hydrogel adhesive. Additionally, the tannin-bearing hydrogel adhesive shows excellent antibacterial properties. This adaptive and antibacterial hydrogel adhesive provides a promising sealant for gastrointestinal surgery and other applications.