Development of Small Molecular Drug-Loaded Microspheres for Enhanced Cartilage Regeneration

Articular cartilage has limited self-repair ability, making osteoarthritis a major challenge due to aging and mechanical stress. While current therapies provide partial functional improvement, their outcomes remain suboptimal, highlighting the need for regenerative strategies. Mesenchymal stem cells (MSCs) show promises due to their chondrogenic potential, and kartogenin (KGN) enhances this process. This study examines KGN-loaded gelatin microspheres (KMs) for cartilage regeneration. KMs were synthesized via gelatin-KGN dispersion in ice-cooled hexane, followed by glutaraldehyde cross-linking. Scanning electron microscopy showed porous KMs (200-800 μm) with interconnected pores (2-10 μm), while Fourier transform infrared spectroscopy confirmed gelatin and KGN presence. hMSCs were cultured with KMs, showing no cytotoxicity. Gene expression analysis revealed upregulated chondrogenic markers (SOX9, ACAN, COMP, COL2A1). Western blotting and immunofluorescence confirmed increased chondrogenic protein production. Sulfated glycosaminoglycan content increased over four weeks, indicating extracellular matrix maturation. This study demonstrates that KMs effectively deliver KGN, enhancing MSC chondrogenesis. Small molecule-based biomaterials may offer an alternative to growth factors in osteochondral tissue engineering, warranting further in vivo validation.