Graphene-like Zinc Substituted Hydroxyapatite

The biological bone minerals form within a complex microenvironment that consists of various ions and template molecules. Silk fibroin provides an attractive template for biomimetic hydroxyapatite synthesis. In this study, graphene-like zinc substituted hydroxyapatite crystals were prepared using silk fibroin and sodium alginate as template molecules, and the resulting products were investigated. The alginate ions interacted with silk fibroin, and the additional zinc ions also influenced the crystal formation of hydroxyapatite. The graphene-like sheets with hydroxyapatite phase were approximately 3 nm in thickness, and the size was more than 100 nm. The structure of the zinc substituted hydroxyapatite was studied by transmission electron microscopy, and the results revealed that small crystallites of several nanometers were assembled into large size sheets. The synergy effect of zinc and alginate ions led to the preferred growth along (002) and (211) orientations. Accordingly, the mechanisms of crystal gr...