In vivo bone regeneration performance of magnesium phosphate/poly dopamine-coated porous titanium biomaterials produced using 3D printing

Objective To evaluation the bone regeneration performance of 3D printed porous titanium biomaterials with magnesium phosphate (MP)/poly dopamine (PDA) coating in vivo. Methods Porous titanium (pTi) scaffolds underwent surface modification with MP/PDA coating by dopamine self-polymerization and sol-gel techniques. The surface modification was characterized by scanning electron microscopy. Animal models of bone defects were created in 30 New Zealand rabbits by drilling holes in bilateral femur lateral condyles, and the rabbits were randomly divided into 3 groups (n=10 in each group): group A treated by filling with MP/PDA-pTi, group B treated by filling with pTi, group C with the defects untreated. CT was performed at 1th day, 4th, 8th and 12th week after operation. The specimens were harvested at 12th week after operation, which were then evaluated by gross observation, Micro-CT and histological examinations. Results The scanning electron microscopy examination revealed that the MP/PDA coating was uniformly deposited on the surface of pTi, with rough surface. Gross observation and CT examination at 12th week postoperatively revealed that defects were being healed completely in group A; bony connection was not achieved in group B; defects were not repaired in group C. Micro-CT revealed that the bone volume fraction values were found to be significantly greater in group A (28.27±4.78)% compared with group B (23.34±7.20)% and group C (10.34±3.27)% (F=60.233, P<0.01). Histological examination revealed that the percentages of bone regeneration values were found to be significantly higher in group A (32.23±3.69)% compared with group B (19.55±4.13)% and group C (5.05±2.63)% (F=295.488, P<0.01). Conclusion Compared with pure pTi scaffolds, MP/PDA-pTi scaffolds possess a better capacity of osteogenesis and osteointegration. Key words: 3D printing; Porous titanium; Surface modification; Bone defect