BMP-2 incorporated biomimetic CaP coating functionalized 3D printed Ti6Al4V scaffold induces ectopic bone formation in a dog model

Abstract

The use of Ti6Al4V in bone engineering is limited, due to the biological inertia of the surface. In this study, a porous Ti6Al4V scaffold with mechanical properties similar to cancellous bone was designed and 3D-printed. Under physiological conditions, the scaffold was immersed firstly in a 5-fold-concentrated sim-ulated body fluid, then in a supersaturated CaP solution containing BMP-2, to form a bone-like porous micro/nano structured biomimetic coating on the surface. Scaffolds were implanted in the muscle pouches created in six beagle dogs and were retrieved four weeks later for histologic and histomorpho-metric analysis. Results showed that BMP-2 integrated biomimetic CaP coating induced ectopic bone for- mation, which was absent in other two groups. Soft tissue infiltrated the scaffold’s outside 1 mm layer, while the new-formed bone was evenly distributed in the longitudinal and horizontal directions withinv the rest of the scaffold based on BA/TA, BIC and BA measurements. In conclusion, the BMP-2 incorporated biomimetic CaP coating creates a micro/nano surface structure on the Ti6Al4V scaffold, which helps to increase biocompatibility. The integrated BMP-2 is capable of inducing ectopic bone formation in vivo