3D printed calcium phosphate scaffolds with controlled release of osteogenic drugs for bone regeneration

The purpose of this research was to repair critical size defects of a skull. First, the CT data on the Beagle's skull were used to reconstruct an implant model. Then two Ф15 mm critical bone defects on the left and right sides of the skull were drilled. Hydroxyapatite, sodium alginate and icariin were adopted to formulate the printing inks according to their proportions. Calcium phosphate scaffolds with accuracy porosity were 3D printed by an extrusion printer. Icariin served as a controlled release of osteogenic drugs for bone regeneration. The physical and chemical properties of the 3D printed scaffolds were summarized, and in vitro and in vivo tests were conducted to assess the biocompatibility and the bone repair ability of the scaffolds. According to the mechanical results, the 3D printed calcium phosphate scaffolds show improved mechanical strength, and the Young's modulus was about 4.23 MPa, while the compressive strength was 9.37 MPa. The drug release test results showed that the slowly controlled release of osteogenic drugs behavior by the 3D printed calcium phosphate scaffolds continuously promoted new bone formation. The in vitro biological assessment results suggested that the 3D printed calcium phosphate scaffolds had good biocompatibility, with no obvious cytotoxicity observed. An animal model, aimed at achieving personalized accurate repair of the critical size defects on the skull, indicated that the 3D printed calcium phosphate scaffolds with controlled release of osteogenic drugs had great potential for regeneration of critical bone defects.