Spatiotemporally programmable hydrogel enables NIR-triggered biofilm disruption and mitophagy-driven immunometabolic...

The refractory nature of periodontitis stems from two interrelated factors: the difficulty in eradicating deeply entrenched pathogenic biofilms and the biofilm-induced impairment of mitochondrial autophagy in immune cells, leading to metabolic dysregulation and persistent inflammation. These processes mutually reinforce each other, creating a self-perpetuating vicious cycle. To address this, we developed a spatiotemporally programmable smart hydrogel (GM hydrogel), constructed on a dynamically crosslinked network of oxidized fucoidan and carboxymethyl chitosan, loaded with silver nanoparticles and EGCG-modified MXene nanosheets (MXene@EGCG-Ag). This near-infrared (NIR) light-responsive platform exhibits excellent injectability, enabling it to completely fill narrow, deep, and irregular periodontal pockets, ensuring intimate contact with pathological sites. The GM hydrogel provides programmed control along both temporal and spatial dimensions. In the temporal dimension, NIR irradiation triggers MXene-mediated mild photothermal effects (<45 °C) that disrupt biofilm structure and facilitate Ag⁺ and EGCG penetration into deeper tissues. In subsequent stages, sustained EGCG release restores mitochondrial autophagy, reprogramming immune cell metabolism to improve the immune microenvironment. Spatially, the hydrogel penetrates mature biofilms and delivers comprehensive treatment from the surface through deep gingiva to the alveolar bone interface. Experimental results demonstrate that GM hydrogel disrupts ionic homeostasis and impairs biofilm functionality in Porphyromonas gingivalis, exhibiting potent antibacterial effects. Sustained EGCG release activates the PINK1/Parkin-mediated FOXO pathway, which restores mitochondrial autophagy and induces metabolic reprogramming, thereby suppressing inflammation and promoting alveolar bone regeneration.