Mussel-Inspired Tough Hyaluronic Acid Modified Hydrogel Dressings with Synergistic Self-Healing, Adhesive and Antibacterial Properties

Promoting the regeneration of bacteria-infected damaged tissues by developing multifunctional tough hydrogels with self-healing, adhesive, remodeling, and antimicrobial properties for use as wound dressings remains a great challenge. Inspired by the excellent adhesion ability of natural mussels, hyaluronic acid (HA) was first oxidized to aldehyde hyaluronic acid (AHA), and then grafted with dopamine (DA) to produce a structure with many catechol groups from which dopamine-grafted hyaluronic acid (DAHA) was prepared and combined with acrylamide (AM), poly(acrylic acid) (PAA), and <i>N</i>,<i>N</i>'-methylenebis(acrylamide) (BIS) to prepare a multifunctional hydrogel (PAD hydrogel). The results indicated that the PAD3 hydrogel with a DAHA content of 3 mg/mL and a BIS monomer content of 0.5 mol %, had high mechanical strength (over 10 MPa), which was 27 times greater than that of pure polyacrylamide (PAM) hydrogels. Furthermore, the PAD hydrogel demonstrated strong antibacterial activity against both Gram-positive and Gram-negative bacteria, and the ability of it to repair infected skin was further investigated in a rat model of <i>Staphylococcus aureus</i> infection. The PAD series hydrogels showed considerable antimicrobial properties and promoted the regeneration of damaged tissues <i>in vivo</i>, suggesting that it can be used as a multifunctional dressing and holds great promise in healing bacteria-infected skin wounds.