The influence of transition metal ions on collagen mineralization

The ions in body fluid play an important role in bone formation besides being a synthesizing material. Transition metal ions Co^2 +, Ni^2 +, Zn^2 +, Fe^3 +, Mn^2 +, Cu^2 +, Cd^2 + and Hg^2 + doped hydroxyapatite (HAP)/collagen composites were synthesized successfully in the presence of collagen traces at mild acidic pH for the first time. However, the amount of doped Hg^2 + and Cd^2 + was relatively low. Meanwhile, through soaking the collagen sponge as a template in simulated body fluid (SBF) which contains different transition metal ions (Mn^2 +, Cu^2 +, Ni^2 +, Co^2 +, Cd^2 +, Hg^2 +), bone-like HAP/collagen composites were synthesized. Hg^2 + had a certain inhibitory effect on the formation of HAP crystals on the surface of the collagen sponge while Co^2 + can promote the formation of HAP on the collagen sponge. For both HAP/collagen composites and HAP/collagen sponge, it was found that transition metal ions Mn^2 + had a significant effect on the morphology of HAP particles and could induce to form floc-like HAP particle aggregates.