The Preparation,Characterization And Properties Of Co-Substutited Nano-Hydroxyapatite

This paper aims at elaborating that the zinc and selenium co-substituted hydroxyapatite(ZnSe0.1HAp)and silicon and selenium co-substituted hydroxyapatite(SiSeHAp)were successfully prepared by chemical co-precipitation and hydrothermal method,respectively.And the samples' drug proteins adsorption/release properties in vitro were investigated with Bull Serum Albumin(BSA)and lysozyme(LSZ)as the drug protein model.Meanwhile,the bioactivity of the prepared ZnSe0.1HAp and SiSeHAp powders were conducted in SBF.In the first segment,the essential features of biomaterials and nano drug carrier materials were outlined in detail.Then the crystal structure,application and preparation methods of hydroxyapatite were introduced,as well as modification by ion-doping.Besides,the mechanism of bioactivity and its significance of hydroxyapatite were also described.The second section mainly introduced the preparation methods of the samples and its characterization.The phase composition and lattice parameters were conducted by X-ray diffraction(XRD).Fourier-transform infrared(FT-IR)spectroscopy was used to analyze the structural compositions and the functional groups.The morphology and size of the samples were detected with scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Energy dispersive X-ray(EDX)spectroscopy,X-ray fluorescence(XRF)spectroscopy and chemical titration method were applied to the quantitative analysis of the elements in the prepared samples.The thermostability of the powders was investigated with thermogravimetric/differential-scanning calorimetry(TG-DSC).Nano particle and zeta potentiometer is used to analyze the samples' polarity and magnitude of the zeta potential in simulated body fluid(SBF).In the third part,Bull Serum Albumin(BSA)and lysozyme(LSZ)were used as the drug protein model to study the proteins adsorption/release properties of ZnSe0.1HAp and SiSeHAp,and the release process was simulated with Higuchi model.The secondary structures of BSA and LSZ were analyzed by fitting programme.In the fourth section,the bioactivity of the prepared ZnSe0.1HAp and SiSe HAp samples were conducted by simulation experiment method in vitro.Chemical titration method was taken to analyze the variations of calcium,phosphorus,zinc,silicon,selenium and magnesium in the powders after soaking in SBF.Besides,the pH values of SBF after soaking were also detected.The preparation and characterization results of ZnSe0.1HAp and SiSe HAp suggested that Zn2+ and SeO32-were successfully incorporated into the intra-cell of hydroxyapatite.SiO44-and SeO32-were also successfully incorporated into the intra-cell of hydroxyapatite.The adsorption tests indicated that loading capacity of ZnSe0.1HAp and SiSe HAp for BSA or LSZ is in direct proportion to the samples' zeta potential in SBF.With higher positive potential,the loading capacity for BSA would enhance.With higher negative potential,the loading capacity for LSZ would increase.While the release tests suggested that ZnSe0.1HAp and SiSeHAp exhibited burst release in the first 12 h.In the following 84 h,the sustained release property would be found.And with the increase of doping agents,the cumulative release amount of BSA and LSZ would be increased.The bioactivity test suggested that the biodegradation process and new bone generation were happened at the same time,which confirmed that ZnSe0.1HAp and SiSeHAp is equipped with good bioactivity.