Electroactive dopamine-functionalized reduced graphene oxide/alginate hydrogel containing thymol/chitosan nanoparticles for advanced antibacterial and bioadhesive wound dressings.

Engineering conductive multifunctional hydrogels, as novel and promising biomaterials, has attracted growing attention in skin tissue engineering and for promoting wound healing. In this study, inspired by recent advances in mussel-inspired chemistry and nanoreinforcement, dopamine-grafted reduced graphene oxide (PDA-rGO) was employed as the main conductive bioadhesive component. Thymol and chitosan nanoparticles were then loaded into the PDA-rGO/alginate hydrogel (Ty/CsNPs@PDA-rGO/Alg), which was synthesized via a simple, Ca2+-mediated radial diffusion crosslinking method to further enhance the antimicrobial activity of the hydrogel. In vitro analysis showed excellent hemocompatibility (hemolysis rates <0.2%), high biocompatibility (>90% cell viability), strong adhesion (∼8.26 kPa), and the highest cell migration rate (∼71.41%) in 3T3 fibroblasts. The hydrogel exhibited valuable mechanical properties, including a compressive strength of 1.03 MPa and a 3.5-fold increase in storage modulus (G') compared to the pristine matrix. The incorporation of Ty/CsNPs into the hydrogel endowed superior antibacterial activity, with inhibition zones of ∼20 mm (S. aureus) and ∼23 mm (E. coli), along with strong antioxidant activity (>80%). Importantly, the developed hydrogel achieved a conductivity of 3.95 mS·cm-1, comparable to that of human skin. Overall, the engineered multifunctional hydrogel demonstrates great potential as a wound dressing, wound monitoring, electrostimulation-assisted therapy, and integration with wearable biosensors.