Author(s):
1. Rebeka Rudolf, University of Maribor, Faculty of Mechanical Engineering, Slovenia
2. Valentina Veselinović, Republic of Srpska, Bosnia and Herzegovina
3. Aleksandra Grebenar, Medicinski fakultet Banja Luka , Republic of Srpska, Bosnia and Herzegovina
4. Vojkan Lazić, University of Belgrade, Faculty of Dental Medicine, Serbia
5. Sergej Tomić, University of Belgrade, Faculty of Dental Medicine, Serbia
6. Miodrag Čolić, University of Belgrade, Faculty of Dental Medicine, Serbia

Abstract:
Ni-Ti alloys with composition 50 at.% Ni and 50 at.% of Ti as one the most applicable biomaterials is produced by the continuous vertical casting process in the form of strands with diameter of 11 mm. This is possible because of involving the completely new approach of continuous casting with the combination of vacuum melting. On the obtained strand the microstructural characterizations in the cross and longitudinal profiles were performed by using a light and Scanning Electron Microscope (SEM) equipped with EDS. Microstructure investigation revealed dendritic distributions of the primary phase and eutectic phase as a matrix. In continuation, the mechanical testing and measurements of hardness were performed. From this continuously casted strand samples were prepared in the form of discs for further treatment with plasma, so that the upper Ni-Ti disc’s surfaces were modified. The second aim was to investigate the potential cytotoxicity of plasma-modified Ni-Ti alloys on L929 cells in vitro. This adherent cell line is recommended by ISO Standards for testing the biocompatibility of medical devices. In addition to the cytotoxicity evaluation, the aim was to assess the adhesion characteristics of L929 cells to the surface of plasma-modified Ni-Ti alloy by using SEM analysis. This information is important for the predictions of biomaterials’ behavior in vivo. In both cases, the experiment was designed to cultivate L929 cells on plasma-modified Ni-Ti alloys or mechanically polished Ni-Ti alloys in complete medium using a constant surface-over-volume ratio (2cm2/ml). Control included the cells cultivated on non-cytotoxic plastic cover slips and non-treated cultures. The cytotoxic effect was evaluated by measuring necrosis and metabolic activity of L929 cells.

Key words:
Ni-Ti alloy,continuous casting,plasma,characterization,mechanical properties,biocompatibility

Thematic field:
SYMPOSIUM B - Biomaterials and nanomedicine

Date of abstract submission:
10.06.2016.

Conference:
Contemporary Materials 2016 - Savremeni Materijali

Abstract