Biodegradable 3D printed HA/CMCS/PDA scaffold for repairing lacunar bone defect

Three-dimensional (3D) printing technology has attracted considerable focus for preparing porous bone repair scaffolds to promote bone regeneration. Inspired by organic-inorganic components and the porous structure of natural bone, novel porous degradable scaffolds have been printed using hydroxyapatite (HA), carboxymethyl chitosan (CMCS), and polydopamine (PDA). The well-designed HA/CMCS/PDA scaffolds exhibited a porous structure with 60.5 ± 4.6% porosity and 415 ± 87 μm in mode pore diameter. The weight loss percentage (WL%) of the HA/CMCS/PDA scaffolds reached about 17% during a 10-week degradation in vitro. The degradation process between the CMCS and HA induced the release of calcium ions. Using commercial product as the contrast material, the osteogenic properties of the scaffolds were assessed in vivo. The implantation and degradation of HA/CMCS/PDA scaffolds had no adverse effects on the kidney and liver of rabbits with no inflammatory response in the implantation sites. The micro-CT and histology data suggested that the HA/CMCS/PDA scaffolds could effectively stimulate new bone formation within the femoral lacuna defect region of rabbits versus blank control at 12 weeks after implantation. Surface cortical bone was generated in the defect area in the HA/CMCS/PDA group; the defect in the blank group remained obvious. HA/CMCS/PDA scaffolds had excellent biodegradability matching the formation of new bone during implantation. In conclusion, 3D-printed HA/CMCS/PDA scaffolds have remarkable potential as a new material for repairing bone defects.