Effect of Zinc Doping on Biological Properties of Biphasic Calcium Phosphate Ceramics in Orthopaedic Animal Model

Addition of dopants in biomaterial has emerged as a vital regulator of bone formation and bone regeneration due to their significant role in the biological processes. We report the effect of zinc ion doping on various properties of biphasic calcium phosphate (BCP) dense body in vitro and in vivo. Zinc (<3 wt%) was successfully incorporated into both calcium hydroxyapatite (HAp) and beta-tricalcium phosphate (TCP) via simple wet chemical route. BCP pellets were prepared by mixing HAp and TCP in a definite proportion, compacted and then sintered. The sintered pellets were checked with XRD, FTIR in addition to hardness and fracture toughness. A systematic in vivo study was conducted to evaluate healing of surgically created defects on the femur of rabbit after implantation of doped and undoped dense BCP for 4 months. Characterization of these sintered dense bodies revealed that zinc dopant had marked influence on the physical properties of the dense bodies as well as their mechanical properties. Fluorochrome labelling, histological analysis and radiology were performed post operation after two and four months to study angiogenesis, bone formation and osseous ingrowth. The findings suggested that addition of Zn dopants to the BCP ceramics demonstrated excellent bone formation and that may pave the new insight in bone tissue engineering.