Effects of cations on surface reactions and apatite nucleation on silicate glasses in a body environment

摘要

Apatite deposition was examined on a series of pseudo binary silicate glasses of composition xM_mO_ncentre dot(50-x/2)(CaOcentre dotSiO_2) (x<10 mol percent; M= Co, Zn, Mn, Cr, W, V,Ta) with thin-film X-ray diffraction, infrared spectroscopy and scanning electron micrograph after they were soaked in a simulated body fluid (Kokubo solution, SBF). The Zn glass was little corrosive. Zn ions remained in the resulted silica gel layer preventing apatite deposition. The Mn and Co ions were released into the SBF as well as stayed in the gel layer where adsorbed calcium phosphates remained amorphous. The Cr-containing glass was similar to the Zn glass regarding bioactivity. Addition of WO_3 shortened the induction time tau of apatite formation. The V glass had a longer tau than the mother glass but causes no effect on the growth of the apatite nuclei.