title: Porous NiTi shape memory alloys produced by SHS: microstructure and biocompatibility in comparison with Ti2Ni and TiNi3.
abstract: Shape memory alloys based on NiTi have found their main applications in manufacturing of new biomedical devices mainly in surgery tools, stents and orthopedics. Porous NiTi can exhibit an engineering elastic modulus comparable to that of cortical bone (12-17 GPa). This condition, combined with proper pore size, allows good osteointegration. Open cells porous NiTi was produced by self propagating high temperature synthesis (SHS), starting from Ni and Ti mixed powders. The main NiTi phase is formed during SHS together with other Ni-Ti compounds. The biocompatibility of such material was investigated by single culture experiment and ionic release on small specimen. In particular, NiTi and porous NiTi were evaluated together with elemental Ti and Ni reference metals and the two intermetallic TiNi3, Ti2Ni phases. This approach permitted to clearly identify the influence of secondary phases in porous NiTi materials and relation with Ni-ion release. The results indicated, apart the well-known high toxicity of Ni, also toxicity of TiNi3, whilst phases with higher Ti content showed high biocompatibility. A slightly reduced biocompatibility of porous NiTi was ascribed to combined effect of TiNi3 presence and topography that requires higher effort for the cells to adapt to the surface.
authors.affiliation: Unit of Lecco, Institute for Energetics and Interphases, National Research Council of Italy - IENI-CNR, Corso Promessi Sposi 29, 23900, Lecco, Italy, paola.bassani@ieni.cnr.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Bassani
authors.forename: Silvia
authors.initials: S
authors.lastname: Panseri
authors.forename: Andrea
authors.initials: A
authors.lastname: Ruffini
authors.forename: Monica
authors.initials: M
authors.lastname: Montesi
authors.forename: Martina
authors.initials: M
authors.lastname: Ghetti
authors.forename: Claudio
authors.initials: C
authors.lastname: Zanotti
authors.forename: Anna
authors.initials: A
authors.lastname: Tampieri
authors.forename: Ausonio
authors.initials: A
authors.lastname: Tuissi
mesh_terms: D000497:Alloys / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D001672:Biocompatible Materials / Q000737:chemistry*; D002478:Cells, Cultured; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry* / Q000494:pharmacology; D010006:Osteoblasts / Q000187:drug effects / Q000502:physiology; D058105:Polymerization; D016062:Porosity; D011208:Powders; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D011208:Powders; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium