title: Ni ion release, osteoblast-material interactions, and hemocompatibility of hafnium-implanted NiTi alloy.
abstract: Hafnium ion implantation was applied to NiTi alloy to suppress Ni ion release and enhance osteoblast-material interactions and hemocompatibility. The auger electron spectroscopy, x-ray photoelectron spectroscopy, and atomic force microscope results showed that a composite TiO(2)/HfO(2) nanofilm with increased surface roughness was formed on the surface of NiTi, and Ni concentration was reduced in the superficial surface layer. Potentiodynamic polarization tests displayed that 4 mA NiTi sample possessed the highest E(br) - E(corr), 470 mV higher than that of untreated NiTi, suggesting a significant improvement on pitting corrosion resistance. Inductively coupled plasma mass spectrometry tests during 60 days immersion demonstrated that Ni ion release rate was remarkably decreased, for example, a reduction of 67% in the first day. The water contact angle increased and surface energy decreased after Hf implantation. Cell culture and methyl-thiazol-tetrazolium indicated that Hf-implanted NiTi expressed enhanced osteoblasts adhesion and proliferation, especially after 7 days culture. Hf implantation decreased fibrinogen adsorption, but had almost no effect on albumin adsorption. Platelets adhesion and activation were suppressed significantly (97% for 4 mA NiTi) and hemolysis rate was decreased by at least 57% after Hf implantation. Modified surface composition and morphology and decreased surface energy should be responsible for the improvement of cytocompatibility and hemocompatibility.
authors: School of Materials Science and Engineering, Beihang University, Beijing, China.
authors: Tingting
authors: T
authors: Zhao
authors: Yan
authors: Y
authors: Li
authors: Xinqing
authors: X
authors: Zhao
authors: Hong
authors: H
authors: Chen
authors: Tao
authors: T
authors: Zhang
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000166:cytology* / Q000378:metabolism; D002460:Cell Line; D003343:Corrosion; D006195:Hafnium / Q000737:chemistry*; D006461:Hemolysis; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry / Q000493:pharmacokinetics*; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D010973:Platelet Adhesiveness; D011817:Rabbits; D051381:Rats; D014025:Titanium / Q000737:chemistry*
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium; D006195:Hafnium