Preparation,Characterization And Properties Of Selenium Doped Hydroxyapatite Biomaterials

The significant research point of this paper is to investigate Se-doped Hydroxyapatite(Se HAp) with different selenium contents via a hydrothermal synthesis method, and their protein adsorption/release properties in vitro. In addition, the bioactivity of Se HAp samples is also evaluated in this experiment at the same time.Firstly, Se HAp with different Se/P ratios were synthesized by treating hydrothermally at 160 °C for 36 h, in which taking calcium nitrate tetrahydrate, diammonium hydrogen phosphate and sodium selenite as the Ca source, P source and Se source, respectively. The Se HAp materials were characterized by powder X-ray diffraction(XRD), Fourier-transform infrared(FT-IR), scanning electron microscopy(SEM), energy dispersive X-ray(EDX) spectroscopy, transmission electron microscopy(TEM), thermogravimetric/differential-scanning calorimetry(TG-DSC), chemical titration analysis and Nano particle and Zeta potentiometer. The experimental results showed that the synthetic Se HAp samples were well-crystallized with a typical apatite structure, the crystallinity and crystal size of SeHAp decreased as the Se concentration increased when the Se/P ratios were less than 0.5, and the selenium was incorporated into the hydroxyapatite lattice by replacing some of phosphate groups with selenite groups. The zeta potentials of Se HAp samples in SBF gradually decreased with increasing selenium content, and all are positive.Secondly, the Se HAp samples were then tested as protein drug carriers by investigating their protein adsorption/release properties, by using bovine serum albumin(BSA) as the model protein. The C site of SeHAp plays an important role in the process of adsorbing BSA, which coincides with Langmuir isotherm. The amount of adsorbed BSA decreased as Se/P molar ratio increased.The SeHAp-BSA samples gave a two stage BSA release profile in SBF at 37 °C over 72 h: the initial burst release in the first 12 h, and continuously slow release in the fol owing time.Finally, the bioactive of samples is reasonably evaluated by in vitro simulation experiment test. When the materials were immersed in SBF, the process concerning biodegradation and new bone ge neration will simultaneously perform. Therefore, the good bioactivity of the SeHAp has been verified.