Our research was designed to evaluate the effect on bone regeneration with 3-dimensional (3D) printed polylactic acid (PLA) and 3D printed polycaprolactone (PCL) scaffolds, determine the more effective option for enhancing bone regeneration, and offer tentative evidence for further research and clinical application. Employing the 3D printing technique, the PLA and PCL scaffolds showed similar morphologies, as confirmed via scanning electron microscopy (SEM). Mechanical strength was significantly higher in the PLA group (63.4 MPa) than in the PCL group (29.1 MPa) (p < 0.01). Average porosity, swelling ratio, and degeneration rate in the PCL scaffold were higher than those in the PLA scaffold. SEM observation after cell coculture showed improved cell attachment and activity in the PCL scaffolds. A functional study revealed the best outcome in the 3D printed PCL-TGF-β1 scaffold compared with the 3D printed PCL and the 3D printed PCL-Polydopamine (PDA) scaffold (p < 0.001). As confirmed via SEM, the 3D printed PCL- transforming growth factor beta 1 (TGF-β1) scaffold also exhibited improved cell adhesion after 6 h of cell coculture. The 3D printed PCL scaffold showed better physical properties and biocompatibility than the 3D printed PLA scaffold. Based on the data of TGF-β1, this study confirms that the 3D printed PCL scaffold may offer stronger osteogenesis.

Bone scaffold surface characterization is important for improving cell adhesion, migration, and differentiation. In this study, bone morphogenetic protein-2 (BMP-2) was immobilized to the surface of the gelatin/hydroxyapatite composite using avidin–biotin binding system to produce a bone-tissue engineering scaffold. Firstly, hydroxyapatite particles reacted with hexamethylene diisocyanate and then the terminal group was converted into a primary amine group. Avidin was then immobilized on the surfaces of hydroxyapatite particles using N-ethyl-N′-(3-(dimethylamino)propyl) carbodiimide and N-hydroxysuccinimide as coupling agents. Gelatin was blended with avidin-modified hydroxyapatite and pure hydroxyapatite to obtain gelain/hydroxyapatite composite. The composite was then cross-linked with glutaraldehyde. Finally, biotin-conjugated BMP-2 was immobilized on the surface of the composite via avidin–biotin binding. In vitro study indicated that BMP-2-immobilized composite film had a higher ALP activity than that composite film without BMP-2. The composite scaffolds were then implanted into rabbit skulls to check bone-tissue regeneration. Ultrasound and micro-CT scans demonstrated that neovascularization and new bone formation in the BMP-2-immobilized composite scaffolds were higher than those in composite scaffolds without BMP-2. Histological evaluation result was similar to that of the micro-CT. Therefore, the surface immobilization of BMP-2 could effectively improve osteogenesis in the gelatin/hydroxyapatite composite scaffold.

Uneven distribution of pores, lack of connection between holes, low reproducibility, insufficient mechanical strength, and incomplete volatility of organic solvents are some problems associated with traditional tissue engineering methods for bone defect repair. These characteristics reduce the quality and stability of products. This study uses 3D printing (3DP) to fabricate a biocompatible poly(lactic) acid‐based scaffold for repairing bone tissue. Hence, three different types of scaffolds are assessed: a freeze‐dried polylactic acid (PLA) scaffold constructed using the traditional freeze‐extraction method; a 3D‐PLA scaffold produced through the 3DP technique; and a 3D‐PLA–bone morphogenetic protein‐2 (BMP‐2) scaffold that is prepared using 3DP technology, with the addition of BMP‐2. To enhance biological activity, polydopamine (pDA) is used to graft BMP‐2 on the surface of the 3D‐PLA–BMP‐2 scaffold. Then, the scaffolds are implanted into the bilateral femoral condyles of rabbits, and their ability to repair the bone tissue defects is tested. The results of the experiments reveal that the 3DP scaffolds are more biocompatible than the ones produced through the traditional manufacturing methods because they enhance cell adhesion and differentiation after pDA modification and BMP‐2 fixation. In the future, the 3DP products may be applied for the repair of larger bone defects in the clinical setting.