fig2

Figure 2. Optical and ultrasound-responsive delivery systems for targeted osteoarthritis therapy. (A) Schematic illustration of NIR-induced chondrogenic differentiation; (B) Western blot analysis of COL-2a and SOX9 protein levels; (C) X-ray analysis of joint space width and osteophyte formation. (A-C) are reprinted from Ref.^[58] with permission; (D) P(AzoAA24-stat-MAA10) polymer was self-assembled into nanobowls. Afterward, MnO₂ nanoparticles were grown in situ onto nanobowls; (E) Mn-nanobowls motion images captured at different ultrasound amplitudes (5,10,15, and 20 Vp-p) in 5 s; (F) The average velocity of Mn-nanobowls was analyzed from the tracking trajectory at different ultrasound amplitudes (n = 3); (G) Penetration assay of ultrasound-propelled Mn-nanobowls in rat knee joints. (D-G) are reprinted from Ref.^[61] with permission. BMSC: Bone marrow-derived mesenchymal stem cell; NCA: nano cationic amylose; KGN: kartogenin; COL-2a: Collagen type II alpha-1; SOX9: SRY-box transcription factor 9; NIR: near-infrared.