Favorable modulation of osteoblast cellular activity on Zr‐modified Co–Cr–Mo alloy: The significant impact of zirconium on cell–substrate interactions

Abstract

Cobalt‐chromium‐molybdenum alloys exhibit good mechanical properties (yield strength: ~530 MPa, ultimate tensile strength: ~1114 MPa, elongation‐to‐failure: ~47.3%, and modulus: ~227 GPa) and corrosion resistance. In recent years, from the perspective of osseointegration, they are considered to be lower in rank in comparison to the widely used titanium alloys. We elucidate here the significant and favorable modulation of cellular activity of Zr‐modified Co–Cr–Mo alloys. The average grain size of Co–Cr–Mo alloy samples with and without Zr was 104 ± 27 and ~53 ± 11 μm, respectively. The determining role of small addition of Zr (0.04 wt. %) to the Co–Cr–Mo alloys in favorable modulation of cellular activity was accomplished by combining cellular biology and materials science and engineering. Experiments on the influence of Zr addition to Co–Cr–Mo alloys clearly demonstrated that the cell adhesion, spread and cell–substrate interactions were enhanced in the presence of Zr. The spread/growth rate of cells was ~120% on the Co–Cr–Mo alloy and 190% per day on the Co–Cr–Mo–Zr alloy. While the % area covered by the cells increased from ~5.1 to ~33.6% on Co–Cr–Mo alloy and ~19.2 to ~47.8% on Co–Cr–Mo–Zr alloy after 2 and 24 hr of incubation. Similarly, the cell density increased from ~1354 to ~3424 cells/cm2 on Co–Cr–Mo alloy and ~3583 to ~7804 cells/cm2 on Co–Cr–Mo–Zr alloy after 2 and 24 hr of incubation. Additionally, stronger vinculin focal adhesion contact and signals associated with actin stress fibers together with extracellular matrix protein, fibronectin, were noted.

Surface roughness and its role in mediating cell adhesion on cobalt‐chromium‐molybdenum alloys

“…While the surface roughness of titanium is well known to influence cell attachment, our study suggests that simply replicating roughness properties on CCM may not yield the same benefits. Therefore, other strategies, such as the immobilisation of biofunctional molecules [39][40][41] on the CCM surface or modification of alloy composition [42,43] should be considered for enhancing the biocompatibility and osseointegration of CCM implants.…”

Bone and Cartilage Interfaces With Orthopedic Implants: A Literature Review

“…Having a similar modulus of elasticity is most likely to ensure the preservation of the implant-tissue interface. Materials having a modulus markedly greater than that of human cortical bone (20 GPa) and trabecular bone (8 GPa), such as aluminum oxide (380 GPa), cobalt-chromiummolybdenum alloy (220-230 GPa), zirconia (210 GPa), and 316 L stainless steel (200 ± 20 GPa), are less likely to sustain longterm implant interface integrity as compared to materials, such as Ti−6Al−4 V titanium-aluminum-vanadium alloy (110 ± 10 GPa) and (PEEK) polyetheretherketone (3.6 GPa) or (CFR-PEEK) carbon-fiber-reinforced polyetheretherketone (18 GPa) which is more malleable (76)(77)(78)(79)(80).…”

Características mecánicas de la fibra de carbono unidireccional y multidireccional en subestructuras implanto soportadas

“…Las estructuras internas de las prótesis hibridas generalmente son elaboradas empleando elementos metálicos 6 como el Ti (Titanio) o aleaciones como el Cr-Co (Cromo Cobalto), sin embargo ambos poseen un módulo de elasticidad de 107Gpa y 225Gpa correspondientemente [7][8] , sin embargo estos valores son distantes al valor de 20Gpa que presenta el tejido óseo. Esta desemejanza entre ambos módulos de elasticidad puede provocar una reabsorción ósea y un fracaso de los implantes 9 .…”