Black phosphorus-based biomaterials for temporomandibular joint osteoarthritis: mechanistic rationale, therapeutic potential, and translational considerations

Background Temporomandibular joint osteoarthritis (TMJOA) is a degenerative joint disorder involving coordinated pathological changes in the synovium, condylar fibrocartilage, and subchondral bone. Current treatments primarily relieve symptoms but have limited capacity to modify progressive tissue degeneration. Black phosphorus (BP) combines redox activity, biodegradability, molecular loading capacity, and near-infrared (NIR) responsiveness, making it a potential platform for simultaneously modulating the joint microenvironment and supporting tissue repair. Methods We integrated current evidence on the cellular and molecular pathology of TMJOA with experimental studies of BP in osteoarthritis, cartilage repair, and bone regeneration. Particular attention was given to synovial immune regulation, oxidative stress and extracellular matrix homeostasis, fibrocartilage repair, subchondral bone remodeling, NIR-responsive biophysical regulation, and BP-based strategies for stabilization, local delivery, tissue targeting, and osteochondral reconstruction. Results TMJOA progression reflects interactions among synovial inflammation, chondrocyte injury, fibrocartilage stem cell (FCSC) dysfunction, abnormal mechanotransduction, and stage-dependent subchondral bone remodeling. BP-based systems can modulate synovial inflammation, reduce oxidative stress and matrix catabolism, and influence bone remodeling. In engineered BP-based systems, mild photothermal stimulation has been reported to affect calcium signaling and mitochondrial function, while material engineering may improve local retention, tissue targeting, and osteochondral repair. However, most evidence derives from knee OA, cartilage-defect, or bone-regeneration models. Direct evidence in TMJOA remains limited, particularly regarding fibrocartilage stem cells, tissue-specific mineralization, osteoblast–osteoclast coupling, and TMJ-specific thermal dosing. Conclusion BP provides a multifunctional material platform capable of integrating microenvironmental regulation, local delivery, NIR-responsive control, and osteochondral repair. Current evidence provides a mechanistic rationale for further investigation of BP-based biomaterials in TMJOA, although a disease-modifying effect in the TMJ has not yet been established. Future studies should define material state, local dose, degradation behavior, and NIR exposure in TMJOA-specific models, while determining whether BP-based systems can support FCSC-mediated chondrogenic repair and maintain lineage stability.