title: In vitro studies on the influence of surface modification of Ni-Ti alloy on human bone cells.
abstract: The in vitro cell behavior on Nitinol after different surface treatments was investigated. As references samples, commercially pure titanium (cpTi) and bioactive titanium were used. The surface treatments influenced the topography, surface energy, crystallographic structure, ion release, chemistry, and ability to form apatite layer from simulated body fluids. Regardless of the surface treatment, the bioactivity study showed that the kinetics of apatite film formation was similar for all tested samples. No clear indication of the surface characteristics influence on the ability for calcium-phosphate precipitation was evident. Cell activity studies showed that ground nickel titanium, spark oxidized and thermally oxidized (at 400 degrees C and below) had higher cellular activity and caused increased alkaline phosphatase (ALP) and osteocalcin (OC) expression which was comparable to control tissue culture plastic and titanium reference samples. Regardless of surface modifications, preimmersion of the samples in media for 72 h resulted in cell proliferation at the same level for all samples. Therefore, it can be concluded that preconditioning of samples alters surface properties and modulates the cell response regardless of the initial surface treatment and its properties. Moreover, a detrimental effect on cell response was observed after 7 and 14 days in culture for alkali treated samples. This was attributed to a high surface nickel concentration and a high nickel ion release rate from these surfaces.
authors.affiliation: Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, University College London, 256 Gray's Inn Road, WC1 X8LD, London, United Kingdom.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Chrzanowski
authors.forename: Ensanya A Abou
authors.initials: EA
authors.lastname: Neel
authors.forename: David A
authors.initials: DA
authors.lastname: Armitage
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Knowles
authors.forename: Vehid
authors.initials: V
authors.lastname: Salih
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry; D000497:Alloys / Q000737:chemistry*; D001842:Bone and Bones / Q000166:cytology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D018360:Crystallography, X-Ray / Q000379:methods; D003470:Culture Media / Q000737:chemistry; D006801:Humans; D066298:In Vitro Techniques; D009532:Nickel / Q000737:chemistry*; D015675:Osteocalcin / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry*; D017155:Wettability
chemical_list: D000497:Alloys; D003470:Culture Media; D015675:Osteocalcin; C040654:titanium nickelide; C013616:nitinol; D009532:Nickel; D014025:Titanium; D000469:Alkaline Phosphatase