An Autolytic High Strength Instant Adhesive Hydrogel for Emergency Self-Rescue

Adhesive hydrogels are promising to be explored as biomedical sealants, hemostatic agents, and glues in promoting wound healing and tissue regeneration. However, it is challenging to engineer a hydrogel combining instant robust adhesion and high strength. Herein, a high-strength instantly self-adhesive organic-inorganic hybrid (OIH) hydrogel by a one-pot radical polymerization of N-acryloyl 2-glycine (ACG), biocompatible glycine derivative vinyl monomer with addition of hydroxyapatite (HAp), naturally occurring mineral is designed and fabricated. The hydrogen bonding from side chain of poly(N-acryloyl 2-glycine) (PACG), carboxyl-Ca2+ ionic crosslinking together with PACG chain-HAp physical interactions contribute to automatic self-repairing high mechanical properties. Importantly, this OIH hydrogel exhibits robust adhesion to diverse substrates, presumably due to synergistic interactions of carboxyl with the substrate surface and the enhanced contact of PACG chains to adherent surfaces facilitated by HAp nanoparticles. Remarkably, the PACG-HAp OIH hydrogels can instantly self-adhere to the soft tissues with adhesion strength of 105 kPa, and anastomose the broken intestines, meanwhile promoting wound healing and stopping bleeding. The OIH hydrogel is autolytic in the body without eliciting inflammatory reaction. Further, the ready-to-use PACG-HAp adhesive hydrogel can be properly stored for a long time. This novel hydrogel will find an appealing application as a new adhesive for emergency self-rescue.