Preparation And Characterization Of The Strontium Substituted Hydroxyapitite Nano Particles

The rapid development of nanotechnology has opened up new areas of application of nanometer biological materials. Inorganic nano particles in the medical applications has become the focus that medical and material scientist pay close attention to together. When certain inorganic nano particles have 1¹00nm small size, they can prevent growth and multiplication of cancer cells while less impact on the normal cells.Hydroxyapatite and different levels of strontium-containing apatite and strontium apatite are prepared through homogeneous co-precipitation method, the gained Sol has stable performance and evenly dispersed nano particles. For he strontium doping, this paper studied in detail three levels (x=0,0.1,0.2)of a type solid solution (Ca_1-xSr_x )₁₀(PO₄)₆(OH)₂(0≤x≤1)and characterize the diameter, size distribution, compared specific surface, and morphology of HAP particles which tested by XRD, FTIR ,TEM and so on.The c axis of the gained hydroxyapatite is elongated while a, b axis are shortened. The growth priority along c orientation is restrained by these changes of crystal lattice parameters. The ratio of length/diameter of the particle becomes smaller. Thus the Ca²⁺ ions are more active in reaction. The reaction activity is the structure base of bioeffects of nano apatite. It enables apatite higher activity.This paper discussed in detail relationship between crystal lattice parameters and morphology through lattice parameters changes of doping strontium or not and different levels.Compared to the pure HAP, strontium doped HAP nano caused lattice distortions inducing linear change of a, c axis because of the introduction of Sr²⁺ led to Sr²⁺ occupy Ca( â…¡ )location of lattice. To the result, diffraction peak of XRD diffraction patterns turned to weaken and broad, the particle size distribution become irregular, the ratio of length/diameter becomes smaller, and crystal grain grow from needle form to short stick even spherical form.This paper studied two factors--range of particle size and quantity of the strontium that impact crystal lattice parameters by orthogonal experiment design, andshowed that the latter one was more notable.With increasing of strontium ions substitution for calcium ions in apatite, the absorption band of hydroxyl group shifts towards high wave numbers. There is regularity between the shift and cation substitution. The wave number of OH' band increases with an increase in the radii of cations of hydroxyapatite owing to the increase in hydrogen bond distance OH—O. The doping of strontium cation in apatite also has effects on P-0 bond in [PO4] tetrahedron. The wave number of PO43" band decreases with an increase of substitution of strontium cations for calcium cations in hydroxyapatite crystals. The shift direction of phosphate anion bang is opposite to that of hydroxyl group band. The array and orientation of [PO4] tetrahedron are affected by the doping of strontium cations;and the length of P-0 bond is changed by them too. These effects result in diversity of physicochemical and biological characteristics of three kinds of apatite.