title: Nanostructured coatings by adhesion of phosphonated polystyrene particles onto titanium surface for implant material applications.
abstract: Titanium that is covered with a native oxide layer is widely used as an implant material; however, it is only passively incorporated in the human bone. To increase the implant-bone interaction, one can graft multifunctional phosphonic compounds onto the implant material. Phosphonate groups show excellent adhesion properties onto metal oxide surfaces such as titanium dioxide, and therefore, they can be used as anchor groups. Here, we present an alternative coating material composed of phosphonate surface-functionalized polystyrene nanoparticles synthesized via free radical copolymerization in a direct (oil-in-water) miniemulsion process. Two types of functional monomers, namely, vinylphosphonic acid (VPA) and vinylbenzyl phosphonic acid (VBPA), were employed in the copolymerization reaction. Using VBPA as a comonomer leads to particles with a higher density of surface phosphonate groups in comparison to those obtained with VPA. VBPA-functionalized particles were used for the coating formation on the titanium surface. The particles monolayer was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM) employing titanium and silicium tip with the native OH groups. Force versus distance curves proves the strong adhesion between the phosphonated particles and the titanium (or silicium) surfaces in contrast to the nonfunctionalized polystyrene particles. Finally, as a proof of concept, the particles adhered to the surface were further used to nucleate hydroxyapatite, which has high potential for bioimplants.
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Zeller
authors.forename: Anna
authors.initials: A
authors.lastname: Musyanovych
authors.forename: Michael
authors.initials: M
authors.lastname: Kappl
authors.forename: Anitha
authors.initials: A
authors.lastname: Ethirajan
authors.forename: Martin
authors.initials: M
authors.lastname: Dass
authors.forename: Dilyana
authors.initials: D
authors.lastname: Markova
authors.forename: Markus
authors.initials: M
authors.lastname: Klapper
authors.forename: Katharina
authors.initials: K
authors.lastname: Landfester
mesh_terms: D002113:Calcification, Physiologic; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D006801:Humans; D018625:Microscopy, Atomic Force; D036103:Nanotechnology / Q000379:methods; D063065:Organophosphonates / Q000737:chemistry*; D016348:Osseointegration; D011137:Polystyrenes / Q000737:chemistry*; D019736:Prostheses and Implants; D011474:Prosthesis Design; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D063065:Organophosphonates; D011137:Polystyrenes; D014025:Titanium