Polysaccharide-CoatedThermosets for Orthopedic Applications:From Material Characterization to In Vivo Tests.

The long-term stability and success of orthopedic implantsdependon the osseointegration process, which is strongly influenced by thebiomaterial surface. A promisingapproach to enhance implant integration involves the modificationof the surface of the implant by means of polymers that mimic thenatural components of the extracellular matrix, for example, polysaccharides.In this study, methacrylate thermosets (bisphenol A glycidylmethacrylate/triethyleneglycoldimethacrylate), a widely used composition for orthopedic and dentalapplications, have been coated by electrostatic deposition of a bioactivechitosan-derivative. This polysaccharide was shown to induce osteoblastsaggregation in vitro, to stimulate cell proliferation and to enhancealkaline phosphatase activity. The coating deposition was studiedby analyzing the effect of pH and ionic strength on the grafting ofthe polysaccharide. Contact angle studies show that the functionalizedmaterial displays a higher hydrophilic character owing to the increaseof surface polar groups. The mechanical properties of the coatingwere evaluated by nanoindentation studies which point to higher valuesof indentation hardness and modulus (E) of the polysaccharidesurface layer, while the influence of cyclic stress on the constructwas assessed by fatigue tests. Finally, in vivo tests in minipigsshowed that the polysaccharide-based implant showed a good biocompatibilityand an ability for osseointegration at least similar to that of thetitanium Ti6Al4V alloy with roughened surface. [ABSTRACT FROM AUTHOR]