ROS-responsive H2S-releasing quaternized chitosan dental implant coating for improved soft tissue integration, antibacterial and immunomodulatory capacities

Early and stable soft tissue integration is a prerequisite for the long-term success of dental implants. Crucially, the formation of this biological seal is closely associated with bacterial invasion and the modulation of the local immune microenvironment. Herein, we developed a reactive oxygen species (ROS)-responsive hydrogen sulfide (H 2 S)-releasing quaternized chitosan (QCS) coating on the transmucosal interface of Ti-6Al-4V implants, termed TC4/PQCS/H 2 S. This coating exhibited favorable biocompatibility, enhancing the adhesion of human gingival epithelial cells (HGECs) and human gingival fibroblasts (HGFs), and improving soft tissue compatibility. Additionally, the TC4/PQCS/H 2 S possessed potent antibacterial activity against Escherichia coli , methicillin-resistant Staphylococcus aureus , and oral anaerobic pathogens, with effective suppression of biofilm formation. Furthermore, the TC4/PQCS/H 2 S enhanced cellular antioxidant defense and activated the Nrf2 pathway. It also promoted macrophage polarization toward the pro-healing M2 phenotype, with the involvement of the PI3K-Akt signaling pathway. Overall, this study presents an efficient surface modification strategy that integrates cell-adhesive, antibacterial, antioxidant, and immunomodulatory functions, demonstrating great potential for soft tissue integration.