A new porous titanium-nickel alloy: Part 1. Cytotoxicity and genotoxicity evaluation.

Porous titanium-nickel (PTN) alloys represent new biomaterials for long-term implantation. Their porosity properties might confer them the capacity to trigger fluid capillarity, tissue ingrowth, as well as good tissue-implant apposition and fixation. Before PTN materials are used as long-term implants, their biocompatibility level must be assessed. In this study, porous titanium-nickel was therefore extracted in a saline semi-physiological solution and materials were evaluated for potential cytotoxicity and genotoxicity reactions. The cytocompatibility elution test was performed in order to determine PTN toxic potential at the in vitro cellular level: no reactivity was detected in cell layers exposed to PTN extracts or the negative controls. In parallel, the genocompatibility of porous titanium-nickel was evaluated using three different assays in order to assess potential damage at the DNA level: the test for chemical induction of chromosome aberrations, the Salmonella typhimurium and Escherichia coli reverse mutation assay, and the mouse micronucleus test. No significant increase in the number of chromosomal aberrations, bacterian revertant colonies, or micronuclei was observed in presence of PTN extracts when compared to negative control exposition. Based on the above results, porous titanium-nickel can be considered completely cytocompatible and genocompatible, and therefore represents a good candidate for long-term implantation.