Recent advances in wet surface tissue adhesive hydrogels for wound treatment

Hydrogels are soft 3D materials that absorb and retain a high amount of water but don't dissolve in it. Bio-adhesives demonstrate great development in the biomedical domain for hemostatic sealing, injured skin regeneration, wound closure, and protecting bio-devices from bio-tissue. These properties render them remarkable future application prospects. Moreover, adhesive hydrogels support wound treatment and management due to their capability of absorbing and retaining a high quantity of water in their 3D network structure, maintaining the wet environment around the wounded sphere, and acting like a natural extracellular matrix. Furthermore, wound dressings are highly applied to support wound treatment, and the conventional method of dressing requires a tape fixation on the traumatic site which is inappropriate within the human body. The internal injury is treated via direct suture which leads to secondary damage to the patient and enhances the infection risk. The adhesive with high adhesive forces integrates with the internal and external wounds firmly and forms a barrier for the prevention of bacterial invasion, enhances the healing process, and prevents suture-caused secondary damage but the presence of fluids such as water and blood on the wound surfaces makes the adhesive hydrogel unfit for wound treatment. Therefore, it is mandatory to achieve robust adhesion in a wet environment. The fabrication of wet adhesive hydrogel with greater adhesion and remarkable biocompatibility has become an imperative current research topic therefore; this review focuses on currently fabricated tissue adhesive hydrogels based on chitosan, phenylboronic acid, catechol, polyphosphazene, hyaluronic acid, starch, and cellulose. This paper also focuses on the wet surface adhesive, anti-bacterial, and self-healing properties of adhesive hydrogels as well as applications of adhesive hydrogels for wound and bone treatment.