Mussel-inspired hydrogels with wet adhesion and anti-inflammatory properties for oral and pressure ulcers

The etiology of oral ulcers is complex, primarily comprising external physical and chemical stimuli, immune imbalances, and various diseases. Pressure ulcers are mainly caused by continuous or intermittent pressure that damages the skin and underlying tissues. The healing process for both types of ulcers is similar to wound healing, including stages such as inflammation, proliferation, and remodeling. However, some clinically used treatments have issues such as significant side effects, high costs, low adhesion, and insufficient mechanical strength, which can negatively affect the patient's physical and mental health. In this study, we designed a mussel-inspired hydrogel (GD3M4), which consists of dopamine-grafted gelatin (GelDA), aldehyde-modified hyaluronic acid (OHA), and methacrylate gelatin (GelMA). This hydrogel can sustain adhesion for 48 hours in artificial saliva. In compression tests, the GD3M4 hydrogel showed a compression modulus of nearly 1.26 MPa, demonstrating excellent compressive strength to adapt to complex in vivo and in vitro environments. The DCFH-DA experiments showed that the GD3M4 hydrogel has good antioxidant properties. In both the mouse oral ulcer model and pressure ulcer model, the GD3M4 hydrogel exhibited excellent ulcer-healing effects by modulating the expression of inflammatory factors and epidermal growth. In conclusion, the GD3M4 hydrogel provides a promising therapeutic strategy for promoting the healing of oral ulcers and pressure ulcers.