Development of carboxylated multi-walled carbon nanotubes and bovine serum albumin reinforced hydroxyapatite for bone substitute applications

The similarity of the chemical composition of hydroxyapatite (HA) to the mineral phase of bone and their excellent biocompatibility meets the requirement of materials designed for bone repair and augmentation purposes. However, the application of HA in load-bearing devices is limited by its poor mechanical properties. Carbon nanotubes (CNTs), with their outstanding stiffness and strength, have good potential applications in tissue engineering. These properties, combined with their small size and large interfacial area, suggest that they may have great potential as a reinforcing agent for HA. The hydroxyapatite/multi-walled carbon nanotubes/bovine serum albumin (HA/MWCNTs-COOH/ BSA) with particle size in the range 20 to 25 nm composites was successfully produced using precipitation technique. The compressive strength of heat-treated composites at 600 to 1000 degrees C is in the range between 27 and 37 MPa. The cytotoxic effect of the composites with different concentrations was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT assay) against normal human colon fibroblast. The developed composites were found to be non-cytotoxic when treated to the human fibroblast cells and imply a proliferative effect on cells. The developed composites are possibly a good choice to use as non-toxic material for bone substitution at the level of the trabecular bone.