title: Polysaccharide-coated thermosets for orthopedic applications: from material characterization to in vivo tests.
abstract: The long-term stability and success of orthopedic implants depend on the osseointegration process, which is strongly influenced by the biomaterial surface. A promising approach to enhance implant integration involves the modification of the surface of the implant by means of polymers that mimic the natural components of the extracellular matrix, for example, polysaccharides. In this study, methacrylate thermosets (bisphenol A glycidylmethacrylate/triethyleneglycol dimethacrylate), a widely used composition for orthopedic and dental applications, have been coated by electrostatic deposition of a bioactive chitosan-derivative. This polysaccharide was shown to induce osteoblasts aggregation in vitro, to stimulate cell proliferation and to enhance alkaline phosphatase activity. The coating deposition was studied by analyzing the effect of pH and ionic strength on the grafting of the polysaccharide. Contact angle studies show that the functionalized material displays a higher hydrophilic character owing to the increase of surface polar groups. The mechanical properties of the coating were evaluated by nanoindentation studies which point to higher values of indentation hardness and modulus (E) of the polysaccharide surface layer, while the influence of cyclic stress on the construct was assessed by fatigue tests. Finally, in vivo tests in minipigs showed that the polysaccharide-based implant showed a good biocompatibility and an ability for osseointegration at least similar to that of the titanium Ti6Al4V alloy with roughened surface.
authors.affiliation: Department of Life Sciences, University of Trieste, Via Giorgieri 1, Trieste I-34127, Italy. atravan@units.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Travan
authors.forename: Eleonora
authors.initials: E
authors.lastname: Marsich
authors.forename: Ivan
authors.initials: I
authors.lastname: Donati
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Foulc
authors.forename: Niko
authors.initials: N
authors.lastname: Moritz
authors.forename: Hannu T
authors.initials: HT
authors.lastname: Aro
authors.forename: Sergio
authors.initials: S
authors.lastname: Paoletti
mesh_terms: D000327:Adsorption; D002448:Cell Adhesion / Q000187:drug effects; D002449:Cell Aggregation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002627:Chemistry, Physical; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry* / Q000494:pharmacology; D009994:Osmolar Concentration; D010006:Osteoblasts / Q000187:drug effects / Q000473:pathology; D010316:Particle Size; D011134:Polysaccharides / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013499:Surface Properties; D014407:Tumor Cells, Cultured
chemical_list: D020099:Coated Materials, Biocompatible; D008689:Methacrylates; D011134:Polysaccharides