Doping metal into calcium phosphate phase for better performance of bone implant materials

For many years calcium phosphate based materials have been used to create bone substitutes as alternatives to human transplant. Most calcium phosphate biomaterials are characterized by high biocompatibility and excellent ability to undergo varying degrees of resorbability. Numerous investigations have been made to study calcium phosphate ceramic materials as bone substitutes. This patent review however, focuses on metal-doped calcium phosphates produced by various methods for clinical applications. A variety of synthesis methods have been employed to produce metal-doped calcium phosphates and different methods may produce different final products and characteristics in terms of crystallinity, morphology and stoichiometry. There are many metal ions such as magnesium (Mg), strontium (Sr), manganese (Mn), iron (Fe), zinc (Zn) and silver (Ag) that have been doped successfully into calcium phosphates to enhance their mechanical and biological properties. These biomaterials can be served as scaffold for bone regeneration with adequate mechanical properties to restore bone defects and facilitate healing process. The significant improvement in certain metal-doped calcium phosphates in terms of physico-chemical, biological and mechanical properties has shown the relevance in the development of metal-doped HA for biomedical applications. This paper provides a review of doping of the most common metals into calcium phosphate phase in order to optimize its performance as bone substitute materials. Some recent patents related to metal doped calcium phosphate ceramics are also reviewed. © 2012 Bentham Science Publishers.