Development and characterization of rhVEGF-loaded poly(HEMA-MOEP) coatings electrosynthesized on titanium to enhance bone mineralization and angiogenesis

Acta Biomater. 2010 Jan;6(1):282-90. doi: 10.1016/j.actbio.2009.07.008. Epub 2009 Jul 14.

Abstract

Osteointegration of titanium implants could be significantly improved by coatings capable of promoting both mineralization and angiogenesis. In the present study, a copolymeric hydrogel coating, poly-2-hydroxyethyl methacrylate-2-methacryloyloxyethyl phosphate (P(HEMA-MOEP)), devised to enhance calcification in body fluids and to entrap and release growth factors, was electrosynthesized for the first time on titanium substrates and compared to poly-2-hydroxyethyl methacrylate (PHEMA), used as a blank reference. Polymers exhibiting negatively charged groups, such as P(HEMA-MOEP), help to enhance implant calcification. The electrosynthesized coatings were characterized by X-ray photoelectron spectroscopy and atomic force microscopy. MG-63 human osteoblast-like cell behaviour on the coated specimens was investigated by scanning electron microscopy, MTT viability test and osteocalcin mRNA detection. The ability of negatively charged phosphate groups to promote hydroxyapatite-like calcium phosphate deposition on the implants was explored by immersing them in simulated body fluid. Similar biological responses were observed in both coated specimens, while calcium-phosphorus globules were detected only on P(HEMA-MOEP) surfaces pretreated with alkaline solution. Testing of the ability of P(HEMA-MOEP) hydrogels to entrap and release human recombinant vascular endothelial growth factor, to tackle the problem of insufficient oxygen and nutrient delivery, suggested that P(HEMA-MOEP)-coated titanium prostheses could represent a multifunctional material suitable for bone restoration applications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biocompatible Materials / chemistry*
  • Calcification, Physiologic / drug effects*
  • Calcium / chemistry
  • Cell Line, Tumor
  • Cell Survival
  • Humans
  • Methacrylates / chemistry*
  • Neovascularization, Physiologic*
  • Osteoblasts / metabolism
  • Phosphorus / chemistry
  • Recombinant Proteins / chemistry
  • Tetrazolium Salts / pharmacology
  • Thiazoles / pharmacology
  • Titanium / chemistry*
  • Vascular Endothelial Growth Factor A / chemistry*

Substances

  • Biocompatible Materials
  • Methacrylates
  • Recombinant Proteins
  • Tetrazolium Salts
  • Thiazoles
  • Vascular Endothelial Growth Factor A
  • Phosphorus
  • 2-hydroxyethyl methacrylate phosphate
  • hydroxyethyl methacrylate
  • Titanium
  • thiazolyl blue
  • Calcium