Comparative in vitro biocompatibility of nickel‐titanium, pure nickel, pure titanium, and stainless steel: genotoxicity and atomic absorption evaluation

Article type: Research Article

Authors: Assad, M.^{; ; ;} | Lemieux, N.^; | Rivard, C.H. | Yahia, L’H.

Affiliations: Centre de Recherche Pédiatrique, Hôpital Ste‐Justine, 3175 Côte Ste‐Catherine, Montréal, (QC), H3T 1C5, Canada | Département de Pathologie et Biologie Cellulaire, Université de Montréal, C.P. 6128, Succ. “Centre‐Ville”, Montréal, (QC), H3C 3J7, Canada | Groupe de Recherche en Biomécanique/Biomatériaux; École Polytechnique de Montréal, C.P. 6079, Succ. “Centre‐Ville”, Montréal, (QC), H3C 3A7, Canada

Note: [] Correspondence to: Michel Assad, Groupe de Recherche en Biomécanique/Biomatériaux, École Polytechnique de Montréal, C.P. 6079, Succ. “Centre‐Ville”, Montréal, (QC), H3C 3A7, Canada. Tel.: 1 (514) 340 4711, ext. 4198; Fax: 1 (514) 340 4611; E‐mail: assadm@hotmail.com.

Abstract: The genotoxicity level of nickel‐titanium (NiTi) was compared to that of its pure constituents, pure nickel (Ni) and pure titanium (Ti) powders, and also to 316L stainless steel (316L SS) as clinical reference material. In order to do so, a dynamic in vitro semiphysiological extraction was performed with all metals using agitation and ISO requirements. Peripheral blood lymphocytes were then cultured in the presence of all material extracts, and their comparative genotoxicity levels were assessed using electron microscopy‐in situ end‐labeling (EM‐ISEL) coupled to immunogold staining. Cellular chromatin exposition to pure Ni and 316L SS demonstrated a significantly stronger gold binding than exposition to NiTi, pure Ti, or the untreated control. In parallel, graphite furnace atomic absorption spectrophotometry (AAS) was also performed on all extraction media. The release of Ni atoms took the following decreasing distribution for the different resulting semiphysiological solutions: pure Ni, 316L SS, NiTi, Ti, and controls. Ti elements were detected after elution of pure titanium only. Both pure titanium and nickel‐titanium specimens obtained a relative in vitro biocompatibility. Therefore, this quantitative in vitro study provides optimistic results for the eventual use of nickel‐titanium alloys as surgical implant materials.

Keywords: Nickel‐titanium, biocompatibility, genotoxicity, electron microscopy, nickel release

Journal: Bio-Medical Materials and Engineering, vol. 9, no. 1, pp. 1-12, 1999