Biocompatibility evaluation of Cu-Al-Ni shape memory alloys

Shape memory alloys belong to a group of smart, functional materials with a unique ability to 'remember' the shape that they had before the pseudo-elastic deformation. Cu-Al-Ni shape memory alloys are today the only available high-temperature SMA, showing good resistance to functional load; however, their biomedical application is still limited. Using melt spinning technique, thin Cu-Al-Ni ribbons can be produced directly from the melt. The aim of our study was to evaluate the biocompatibility of Cu-Al-Ni alloys in vitro. Thin Cu-Al-Ni ribbons were produced by the technique of melt spinning and were used for the tests. The base alloy for casting of the same composition, but without shape memory effect, was used as a control. The results of MTT test showed that Cu-Al-Ni base alloys (alloys control) almost completely reduced the metabolic activity of peripheral blood mononuclear cells (PBC), while none of the Cu-Al-Ni ribbon types showed a statistically significant effect on the metabolic activity of cells compared with control (cells cultivated only in the medium). Rapidly solidified ribbons with memory effect stimulate the production of proinflammatory cytokines, but not Th1 and Th2 cytokines by activated PBC. However, in addition to IL-1 β, their stimulatory potential is significantly lower compared to the control Cu-Al-Ni alloy.