A flexible adhesive hydrogel dressing of embedded structure with pro-angiogenesis activity for wound repair at moving parts inspired by commercial adhesive bandages

Compared with the wound in the flat part of human body, the repair of the wound in the joint, armpit and other frequently moving parts is still a complex problem. Although many flexible and adhesive hydrogel dressings for the repair of wounds at moving parts have been developed, in order to improve their flexibility and adhesion, most hydrogel dressings use synthetic polymers and natural polymers to form composite hydrogels, which greatly reduces their biocompatibility and bioactivity compared with a single natural polymer hydrogel. They can only passively provide a barrier to the wound and the process of wound repair is slow, which seriously hinders their further application. Inspired by commercial adhesive bandages, we have successfully constructed a flexible adhesive hydrogel dressing of embedded structure with pro-angiogenesis activity. The hydrogel was prepared by the adhesive and non-adhesive parts by topological adhesion and molecular entanglement. Due to the high-density hydrogen bonding, hydrogels possessed good adhesion and flexibility, which allowed them to repair wounds of moving parts successfully. In addition, the non-adhesive part loaded with exosomes was directly in contact with the wound, minimizing the stimulation of the wound tissue by cytotoxic materials, and continuously releasing active substances to promote vascular regeneration. This biocompatible flexible and adhesive hydrogel dressing with pro-angiogenesis activity shows strong potential in wound tissue remodeling, providing a new strategy for the treatment of moving parts or sensitive wound parts.