Cation-π driven innovative gelatin-based hydrogels with ultrahigh adhesion and self-healing capabilities

Tissue adhesives are critical for wound healing, facilitating tissue bonding and attachment to non-biological surfaces. Bio-based adhesives, such as gelatin, are attractive due to their inherent biocompatibility, biodegradability, and low immunogenicity. However, traditional gelatin-based adhesives suffer from limitations including low crosslink density, high hydrophilicity, and suboptimal surface adhesion, resulting in weak mechanical strength and inadequate adhesion. Drawing inspiration from the cation-π interaction observed in mussel adhesive proteins, a novel hydrogel with high mechanical strength and adhesion was synthesized developed by grafting N-Benzyloxycarbonyl-L-Glutaminylglycine (ZQG) onto the gelatin peptide chain and 3-(carboxypropyl)trimethyl-ammonium chloride (CPTA) onto the polylysine chain. The optimized hydrogel, designated Gel-Z-C(0.5), demonstrated exceptional performance, exhibiting impressive dry and adhesion on porcine skin strengths of 298.78 ± 36.24 kPa and 150.69 ± 9.34 kPa, respectively. Remarkably, Gel-Z-C(0.5) also displayed rapid self-healing within 70 min and excellent compressive strength (100 kPa at 85 % strain). These superior properties are attributed to the synergistic interplay of cation-π, π-π, and electrostatic interactions, fostering a robust multi-crosslinked network. Furthermore, this innovative hydrogel exhibits controlled swelling, appropriate biodegradability, and excellent biocompatibility. These findings strongly suggest the material’s potential as an effective biomedical tissue adhesive, driven by its robust adhesion, outstanding mechanical strength, and self-healing.