Synthesis of silver-incorporated hydroxyapatite nanocomposites for antimicrobial implant coatings

Because of excellent osteoconductivity and resorbability, hydroxyapatite (HA) is commonly used as a bone substitute material or implant coating. Both ionic and metallic silver are considered to have a broad spectrum of antimicrobial properties especially associated with biomaterial-related infections. The present work proposes a facile chemical reduction method to synthesize an Ag incorporated HA nanocomposite. Ammoniacal silver solution was firstly prepared and then added into the HA solution, followed by hydrazine hydrate (N2H4·H2O) being used to reduce the silver ions to metallic silver. The formed Ag nanoparticles had diameters of 20-30 nm and were firmly attached on the HA particle surfaces. This approach can also keep the integrity of the HA chemical structure and the morphology. The strain Escherichia coli was used to evaluate the antibacterial effect of the nanocomposite. An In vitro bacterial adhesion study indicated a significant enhancement in the antibacterial property of silver containing HA.