Hydroxyapatite (HA) co-doped with Zn 2 þ and F À ions was synthesized by precipitation method for the first time in this study. FTIR spectroscopy revealed Zn 2 þ and F À ions incorporation into HA structure. Co-doping of Zn 2 þ and F À ions decreased unit cell volume of HA and decreased grain sizes. Zn 2 þ or 5 mol% F À addition into HA significantly improved its density. Microhardness was increased with Zn 2 þ addition and further increase was detected with F À co-doping. Zn 2 þ and F À co-doped samples had higher fracture toughness than pure HA. Zn 2 þ incorporation to the structure resulted in an increase in cell proliferation and ALP activity of cells, and further increase was observed with 1 mol% F À addition. With superior mechanical properties and biological response 2Zn1F is a good candidate for biomedical applications.

No abstract

No abstract

In this study, hydroxylapatite (HA) doped with Zn 2z and/or Cl 2 ions was synthesised by precipitation method and sintered at 1100uC for 1 h. Densities of the samples were measured by the Archimedes method. Zn 2z addition increased the density significantly, while Cl 2 increased the density insignificantly. Hydroxylapatite phase and inconsiderable amount of CaO phase were detected in some samples according to the X-ray diffraction results. Cl 2 added samples (2?5 mol.-%) increased the hexagonal unit cell volume of HA. Characteristic PO 32 4 and OH 2 bands of HA were detected in Fourier transform infrared spectroscopy. Cl 2 related band was also observed at a wavenumber of 3497 cm 21 . Grain sizes of the samples decreased with Cl 2 addition and increased with Zn 2z addition according to the SEM images. Zn 2z and Cl 2 addition improved the microhardness of pure HA. Fracture toughness of the samples decreased with Cl 2 and Zn 2z addition. When compared with other compositions, 2Zn2?5ClHA produced the best results in terms of mechanical properties.

Hydroxyapatite has been widely used in biomedical applications as a coating material for implant surfaces, a drug carrier, a scaffold or composite for bone tissue engineering applications. The highly ionic structure of hydroxyapatite allows doping of various ions, resulting in an improvement in its properties. Boron is one of the elements which can be doped into hydroxyapatite structure by replacing phosphate (PO 4 3-) or hydroxyl (OH-) sites to obtain scaffolds for bone tissue engineering applications or a coating material for metal substrates. Although the effects of supplemental boron on bone, liver, and brain metabolism have been shown to have important results as a nutrient, there are very few studies in the literature on the use of boron-doped hydroxyapatite in the biomedical field. In this review, the details of synthesis methods and functional groups of boron-doped hydroxyapatite were tabulated. Generally, the addition of boron leads to the formation of rod-like morphology, while the density and Vicker's microhardness of hydroxyapatite decrease. Thermal stability and electrical insulation properties were observed to improve with boron doping. Boron was also shown to increase biodegradability, bioactivity as well as cell proliferation and differentiation of different cell types on the surface of hydroxyapatite.