Organic-inorganic hybrid coatings containing phosphorus precursors prepared by sol– gel on Ti6Al4V alloy: Electrochemical and in-vitro biocompatibility evaluation

Abstract

The durability and long-term success of metallic implants are enhanced through the molecular scale design of biocompatible and corrosion resistant surface coatings. To pursue this hypothesis, we have developed a new class of organic-inorganic (O-I) hybrid nanocomposite coatings based on tetramethylorthosilicate (TMOS) and γ-methacryloxypropyltrimethoxysilane (MAPTMS) as organofunctional alkoxysilanes precursors and dimethyltrimethylsilylphosphite (DMTMSP) as a phosphorus precursor. Addition of DMTMSP to TMOS-MAPTMS hybrids increased the extent of intermolecular condensation and cross-linking observed. Both normal human osteoblast in-vitro biocompatibility and corrosion resistance were enhanced in coatings containing DMTMSP. Though increasing phosphorous content correlated with biocompatibility, a compromise in the amount of phosphorus incorporated would be required if corrosion resistance was the most desirable parameter for optimization, at least for single coat systems. Evaluation of the electrochemical behaviour and the in-vitro biocompatibility show that films prepared using these materials by dip coating onto Ti6Al4V alloys offer a promising alternative to simpler coatings and wholly metallic prostheses.