title: Relationship between microstructure, cytotoxicity and corrosion properties of a Cu-Al-Ni shape memory alloy.
abstract: Cu-Al-Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but their biomedical application is still limited. The aim of this work was to compare the microstructure, corrosion and cytotoxicity in vitro of a Cu-Al-Ni SMA. Rapidly solidified (RS) thin ribbons, manufactured via melt spinning, were used for the tests. The control alloy was a permanent mould casting of the same composition, but without shape memory effect. The results show that RS ribbons are significantly more resistant to corrosion compared with the control alloy, as judged by the lesser release of Cu and Ni into the conditioning medium. These results correlate with the finding that RS ribbons were not cytotoxic to L929 mouse fibroblasts and rat thymocytes. In addition, the RS ribbon conditioning medium inhibited cellular proliferation and IL-2 production by activated rat splenocytes to a much lesser extent. The inhibitory effects were almost completely abolished by conditioning the RS ribbons in culture medium for 4 weeks. Microstructural analysis showed that RS ribbons are martensitic, with boron particles as a minor phase. In contrast, the control Cu-Al-Ni alloy had a complex multiphase microstructure. Examination of the alloy surfaces after conditioning by energy dispersive X-ray and Auger electron spectroscopy showed the formation of Cu and Al oxide layers and confirmed that the metals in RS ribbons are less susceptible to oxidation and corrosion compared with the control alloy. In conclusion, these results suggest that rapid solidification significantly improves the corrosion stability and biocompatibility in vitro of Cu-Al-Ni SMA ribbons.
authors.affiliation: Institute of Medical Research, Military Medical Academy, Crnotravska 17, 11002 Belgrade, Serbia. vmaimi@eunet.rs
authors.forename: Miodrag
authors.initials: M
authors.lastname: Colić
authors.forename: Rebeka
authors.initials: R
authors.lastname: Rudolf
authors.forename: Dragoslav
authors.initials: D
authors.lastname: Stamenković
authors.forename: Ivan
authors.initials: I
authors.lastname: Anzel
authors.forename: Dragana
authors.initials: D
authors.lastname: Vucević
authors.forename: Monika
authors.initials: M
authors.lastname: Jenko
authors.forename: Vojkan
authors.initials: V
authors.lastname: Lazić
authors.forename: Gorazd
authors.initials: G
authors.lastname: Lojen
mesh_terms: D000497:Alloys / Q000737:chemistry*; D000535:Aluminum / Q000737:chemistry*; D000818:Animals; D017209:Apoptosis; D001672:Biocompatible Materials / Q000737:chemistry*; D002470:Cell Survival; D003300:Copper / Q000737:chemistry*; D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry*; D008297:Male; D051379:Mice; D009532:Nickel / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D051381:Rats; D013154:Spleen / Q000166:cytology; D013499:Surface Properties; D013778:Tetrazolium Salts / Q000737:chemistry; D013844:Thiazoles / Q000737:chemistry; D013950:Thymus Gland / Q000166:cytology
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D003722:Dental Alloys; D013778:Tetrazolium Salts; D013844:Thiazoles; D003300:Copper; D009532:Nickel; D000535:Aluminum; C022616:thiazolyl blue; D010100:Oxygen