Poly(lipoic acid)-Based Bioresorbable Antiswelling Bioadhesive for Wet/Underwater Tissue Adhesion

Wound closure by suture and staple demands surgical skills and carries risks of traumatic complications, whereas current tissue adhesives exhibit insufficient wet adhesion strength, unsatisfactory in vivo biodegradability, and durability. Inspired by the robust underwater adhesion of mussels, whose underwater adhesion derives from the synergy of hydrophobic and adhesive matrix, a tough bioadhesive (PLD) was developed by coassembly of lipoic acid (LA) and a dopamine-functionalized lipoic acid derivative (LAD). Mimicking the mussel's adhesion mechanism, PLD expelled interfacial water via hydrophobic chains, enabling catechol and carboxyl groups to form robust bonds with wet tissue. It exhibited water-strengthened underwater adhesion (approximately from 37.06 to 50.23 kPa after 180 min water immersion) due to water-activated aggregation of hydrophobic chains. Owing to the combined effect of hydrogen bonds, π-π interaction, and hydrophobic associations, PLD displayed durable wet adhesion because it had exceptional antiswelling properties with a remarkably low swelling ratio of 2.07% after 72 h in a physiological environment. In addition, it was bioresorbable, cytocompatible, and histocompatible. The PLD adhesive may offer a promising and multifunctional alternative to conventional sutures for wound closure.