Discovery of Ti-Binding Abilities of Phosphorylated-Chitin and -Collagen

Abstract

Previously we have discovered that titanium (Ti) binds with bone phosphoproteins SIBLING protein family, by using a Ti beads chromatography. Furthermore, we showed that the isolated bone phosphoproteins remarkably enhanced bone formation when we coated the Ti device with them and implanted into rat calvaria. Therefore, we have called the Ti-binding bone phosphoproteins as “the implant proteins.” This discovery encouraged us to create a new biomolecule that can simulate the functions of the implant proteins. Since significant characteristics of the implant proteins are the presence of multiple phosphate groups and the occurrence of single cell-adhering RGD sequence, we decided for the first place to phosphorylate chitin and collagen to see whether they acquire or increase Ti-binding ability. Results showed that more than 70% of phosphorylated chitin bound with Ti, and phosphorylated collagen enhanced about 7% of its Ti-binding ability. These modified biomolecules, P-chitin and P-collagen will become highly useful for new development of Ti-related bone regenerative medicine.