Suppression of mechanical instability in bioabsorbable ultrafine-grained Zn through in-situ stabilization by ZnO nanodispersoids

0579134 - FZÚ 2024 RIV NL eng J - Journal Article
Balog, M. - de Castro, M.M. - Čapek, Jaroslav - Švec Jr., P. - Takáčová, M. - Csáderová, L. - Sedláčková, E. - Švastová, E. - Školáková, Andrea - Dvorský, Drahomír - Pinc, Jan - Hybášek, V. - Kubásek, J. - Krížik, P. - Skiba, J. - Bajana, O. - Ibrahim, A.M.H.
Suppression of mechanical instability in bioabsorbable ultrafine-grained Zn through in-situ stabilization by ZnO nanodispersoids.
Journal of Materials Research and Technology-JMR&T. Roč. 25, July (2023), s. 4510-4527. ISSN 2238-7854. E-ISSN 2214-0697
R&D Projects: GA MŠMT(CZ) EF16_019/0000760
Grant - others:OP VVV - SOLID21(XE) CZ.02.1.01/0.0/0.0/16_019/0000760
Research Infrastructure: CzechNanoLab II - 90251
Institutional support: RVO:68378271
Keywords : bioabsorbable * in-vitro * mechanical properties * metal matrix composite (MMC) * zinc (Zn) * zinc oxide (ZnO)
OECD category: Materials engineering
Impact factor: 6.4, year: 2022
Method of publishing: Open access

he issue of intrinsic microstructural and mechanical instability of Zn-based metals limits their expansion in potential applications of bioresorbable stents and orthopedic fixators. A new concept of stabilization of Zn microstructure by a small fraction of nontoxic nanometric ZnO dispersoids is proposed for the first time and demonstrated on the particular bioabsorbable model material. The effect of the ZnO dispersoids on post-processing microstructural stability, deformation and strengthening mechanisms, corrosion, and in-vitro biological behavior are pursued. The ZnO dispersoids arise in situ within deformed Zn structure during the consolidation of fine atomized Zn 99.99wt.% powder by hydro-extrusion. ZnO nanodispersoids (4.75 vol.%, ∼136 nm) form from passivating films present on Zn. They allow formation of ultrafine-grained Zn structure with an average grain size of ∼750 nm and its retention by Zener pinning action during annealing held at 100 °C. The model Zn + ZnO composite shows the superior mechanical properties than those reported for pure Zn materials. The utilized stabilization concept doesn't compromise corrosion and biological responses. Immersion of the Zn + ZnO in DMEM results in a corrosion rate, which complies with the desirable standard rate for biodegradable materials. Electrochemical tests suggest that the Zn + ZnO reaches a similar degradation rate after the first week of immersion and a more uniform corrosion behavior compared to the cast Zn reference. In-vitro cyto/genotoxicity assays performed using DMEM diluted extracts of the Zn + ZnO and cast Zn incubated with L929 cells yield in comparable and non-toxic responses. The presence of ZnO dispersoids induces a small but still significant bacteriostatic activity.
Permanent Link: https://hdl.handle.net/11104/0347996