Assessment of injectable and cohesive nanohydroxyapatite composites for biological functions.

Pressing need for utilization of injectables/fillers in various forms of orthopaedic treatments/surgeries commands an equal demand for better graft material. Injectable bone graft material based on biomimetically synthesized nanohydroxyapatite was developed and subjected to ball milling for different times; three materials thus produced were evaluated for their biological properties. The three composites tested were found to have some difference in proliferation and differentiation on mesenchymal stem cells in cultures. In vivo studies were performed by implanting the graft materials with or without cells in the bone drill hole injury created in the femur of Wistar rats. Our studies show that the composites lead to well-healed injury site with normal histology without inflammation or fibrous tissue formation and bone deformity. This material needs to be tested on large animals for further ascertaining its applicability in clinical use.