Phosphorylated chitin increased bone formation when implanted into rat calvaria with the Ti-device

Biomed Mater Eng. 2020;31(1):47-57. doi: 10.3233/BME-201079.

Abstract

Background: Previously we found that a group of phosphorylated proteins (SIBLINGs) in bone binds with the Ti-device, and increases the early bone formation around the Ti-implants remarkably. From these results, we explained the biochemical mechanism of a strong bond between living bone and Ti, which was discovered by Brånemark and colleagues. For the clinical application of our findings, we need a large amount of these proteins or their substitutes.

Objective: We aimed to create a new molecule that equips with essential functions of SIBLINGs, Ti-binding, and bone enhancement around the Ti implant.

Methods: We chemically phosphorylated chitin and obtained a soluble form of phosphorylated chitin (P-chitin). In this solution, we immersed the Ti-devices of web-form (TW) which we previously developed and obtained the P-chitin coated TWs. Then we tested the P-chitin coated TWs for their calcification ability in vitro, and bone enhancing ability in vivo, by implanting them into rat calvaria. We compared the P-chitin coated TW and the non-coated TW in regard to their calcification and bone enhancing abilities.

Results: Ti-devices coated with phosphorylated-chitin induced a ten times higher calcification in vitro at 20 days, and four times more elevated amount of bone formation in vivo at two weeks than the uncoated Ti-device.

Conclusions: Phosphorylated chitin could be a partial substitute of bone SIBLING proteins and are clinically applicable to accelerate bone formation around the Ti implants, thereby achieving the strong bond between living bone and Ti.

Keywords: Chitin; Ti-device; enhanced bone formation; phosphorylation.

MeSH terms

  • Animals
  • Bone Regeneration / drug effects
  • Calcification, Physiologic / drug effects
  • Chitin / chemistry
  • Chitin / metabolism
  • Chitin / pharmacology*
  • Coated Materials, Biocompatible / chemistry
  • Coated Materials, Biocompatible / pharmacology
  • Implants, Experimental*
  • Male
  • Materials Testing
  • Osteogenesis / drug effects*
  • Phosphoproteins / chemistry
  • Phosphoproteins / pharmacology*
  • Phosphorylation
  • Rats
  • Rats, Wistar
  • Skull* / drug effects
  • Skull* / metabolism
  • Skull* / pathology
  • Skull* / physiopathology
  • Surface Properties / drug effects
  • Titanium / chemistry*
  • Titanium / pharmacology

Substances

  • Coated Materials, Biocompatible
  • Phosphoproteins
  • Chitin
  • Titanium