title: Surface characteristics, mechanical properties, and cytocompatibility of oxygen plasma-implanted porous nickel titanium shape memory alloy.
abstract: Good surface properties and biocompatibility are crucial to porous NiTi shape memory alloys (SMA) used in medical implants, as possible nickel release from porous NiTi may cause deleterious effects in the human body. In this work, oxygen plasma immersion ion implantation (O-PIII) was used to reduce the amount of nickel leached from porous NiTi alloys with a porosity of 42% prepared by capsule-free hot isostatic pressing. The mechanical properties, surface properties, and biocompatibility were studied by compression tests, X-ray photoelectron spectroscopy (XPS), and cell culturing. The O-PIII porous NiTi SMAs have good mechanical properties and excellent superelasticity, and the amount of nickel leached from the O-PIII porous NiTi is much less than that from the untreated samples. XPS results indicate that a nickel-depleted surface layer predominantly composed of TiO(2) is produced by O-PIII and acts as a barrier against out-diffusion of nickel. The cell culturing tests reveal that both the O-PIII and untreated porous NiTi alloys have good biocompatibility.
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.
authors.forename: S L
authors.initials: SL
authors.lastname: Wu
authors.forename: Paul K
authors.initials: PK
authors.lastname: Chu
authors.forename: X M
authors.initials: XM
authors.lastname: Liu
authors.forename: C Y
authors.initials: CY
authors.lastname: Chung
authors.forename: J P Y
authors.initials: JP
authors.lastname: Ho
authors.forename: C L
authors.initials: CL
authors.lastname: Chu
authors.forename: S C
authors.initials: SC
authors.lastname: Tjong
authors.forename: K W K
authors.initials: KW
authors.lastname: Yeung
authors.forename: W W
authors.initials: WW
authors.lastname: Lu
authors.forename: K M C
authors.initials: KM
authors.lastname: Cheung
authors.forename: K D K
authors.initials: KD
authors.lastname: Luk
mesh_terms: D000497:Alloys; D000818:Animals; D000831:Animals, Newborn; D001672:Biocompatible Materials; D002478:Cells, Cultured; D051379:Mice; D009532:Nickel; D010006:Osteoblasts; D010100:Oxygen; D016062:Porosity; D014025:Titanium
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D009532:Nickel; D014025:Titanium; D010100:Oxygen