Biological evaluation of nano-hydroxyapatite-zirconia (HA-ZrO2) composites and strontium-hydroxyapatite (Sr-HA) for load-bearing applications.

The biological response of strontium (Sr) doped hydroxyapatite (HA) and hydroxyapatite–zirconia (HA–ZrO2) composites produced by employing sol–gel technology, minimal ZrO2 loadings, and novel microwave-sintering regimes thereby retarding decomposition, is reported. In vitro evaluations indicate that all materials induce a favorable response from rat osteosarcoma cells. In vivo evaluations show osteoconductivity and biocompatibility for both the Sr–HA and HA–ZrO2. The materials did not cause any inflammatory response in bone. The Sr–HA displays better biocompatibility which may be due to the incorporation of Sr and the formation of a surface apatite layer.