Fabrication of 3-Dimensional-Printed Bilayered Scaffold Carboxymethyl Chitosan/Oxidized Xanthan Gum, Biphasic Calcium Phosphate for Osteochondral Regeneration.

Cartilage tissue regeneration remains challenging due to the tissue's poor self-healing capacity, attributed to its hypocellular and avascular nature, which limits nutrient delivery to the defect site and complicates healing. Traditional methods often utilize the subchondral tissue layer to improve nutrient exchange through its vascular network, although these approaches have limitations. To address these issues, 3-dimensional (3D) printing has been employed to create the bilayered scaffold that mimics the complex structure of osteochondral tissue. In this study, the N,O-carboxymethyl chitosan (NOCC) and oxidized xanthan gum (OXG) hydrogel was fabricated for the cartilage layer due to its similarity to the native cartilage structure, while the biphasic calcium phosphate (BCP) incorporation enhanced the osteoconductivity to promote new bone growth for osteochondral tissue regeneration. Various characterization tests, including compression strength, scanning electron microscopy analysis, and biological properties, were conducted to evaluate and balanced to achieve the highest regenerative capacity for implantation. No cytotoxicity was caused, while the in vitro testing highlighted that the addition of BCP considerably supported cellular behavior on the scaffold and improved the regeneration rate. With 60% BCP content, the 3D scaffold demonstrated a high osteochondral tissue regeneration rate, as evidenced by visual inspection, x-ray imaging, and histological analysis, outperforming other experimental models.