Biological Behaviour and Enhanced Anticorrosive Performance of the Nitrided Superelastic Ti-23Nb-0.7Ta-2Zr-0.5N Alloy

Abstract

The influence of gas nitriding surface treatment on the superelastic Ti-23Nb-0.7Ta-2Zr-0.5N alloy was evaluated. A thorough characterization of bare and nitrided Ti-based alloy and pure Ti was performed in terms of surface film composition and morphology, electrochemical behaviour, and short term osteoblast response. XPS analysis showed that the nitriding treatment strongly influenced the composition (nitrides and oxynitrides) and surface properties both of the substrate and of the bulk alloy. SEM images revealed that the nitrided surface appears as a similar dotted pattern caused by the formation of N-rich domains coexisting with less nitrided domains, while before treatment only topographical features could be observed. All the electrochemical results confirmed the high chemical stability of the nitride and oxynitride coating and the superiority of the applied treatment. The values of the corrosion parameters ascertained the excellent corrosion resistance of the coated alloy in the real functional conditions from the human body. Cell culture experiments with MG63 osteoblasts demonstrated that the studied biomaterials do not elicit any toxic effects and support cell adhesion and enhanced cell proliferation. Altogether, these data indicate that the nitrided Ti-23Nb-0.7Ta-2Zr-0.5N alloy is the most suitable substrate for application in bone implantology.

Deformation Mechanisms and Biocompatibility of the Superelastic Ti–23Nb–0.7Ta–2Zr–0.5N Alloy

“…These observations have revealed the typical appearance of osteoblast cells with well-expressed stress fibers oriented parallel to one another and to the long axis of the cell and punctiform vinculin signals at the termini of actin microfilament bundles. On the other hand, no significant differences in terms of cell spreading, cytoskeleton organization, and focal contact formation could be observed between Ti-23Nb-0.7Ta-2Zr-0.5N and CP-Ti [29]. Taken together, these findings prove that the studied Ti-23Nb-0.7Ta-2Zr-0.5N alloy favors cell proliferation without showing any deleterious effect suggesting increased biocompatibility.…”

“…By day 5, the proliferation rates on the two surfaces were significantly higher than those found after 1 and 3 days of culture. In a very recent study [29], we have observed on the Ti-23Nb-0.7Ta-2Zr-0.5N alloy the cell-to-substrate interaction by double fluorescent staining of vinculin and actin filaments. These observations have revealed the typical appearance of osteoblast cells with well-expressed stress fibers oriented parallel to one another and to the long axis of the cell and punctiform vinculin signals at the termini of actin microfilament bundles.…”

“…Consequently, the Ti-23Nb-0.7Ta-2Zr-0.5N alloy possesses a perfect chemical stability, which is due to the presence of the alloying elements. Indeed, the composition and the thickness of native passive film formed on the Ti-23Nb-0.7Ta-2Zr-0.5N alloy was analyzed by X-ray photoelectron microscope in a previous study [29]. It was detected a dense passive layer of about 6.5 nm composed of oxides and oxynitrides of the transition Ti, Nb, Zr, Ta metals that assured the alloy structural integrity and anticorrosion resistance.…”

Graphene nanoplatelets-sericin surface-modified Gum alloy for improved biological response

“…For this, the pre-osteoblast cells grown on the above substrates were fixed, permeabilized, blocked and incubated with specific antibodies, as previously reported. 53 Subsequently, phalloidin coupled with Alexa Fluor 488 was added in order to label actin filaments and, then, 4′,6-diamidino-2-phenylindole (DAPI) to visualize the nuclei. Labelled samples were washed three times with PBS and examined under an inverted microscope equipped with epifluorescence (Olympus IX71).…”