Evaluation of a Zn–2Ag–1.8Au–0.2V Alloy for Absorbable Biocompatible Materials

Abstract

Zinc (Zn) and Zn-based alloys have been proposed as a new generation of absorbable metals mainly owing to the moderate degradation behavior of zinc between magnesium and iron. Nonetheless, mechanical strength of pure Zn is relatively poor, making it insufficient for the majority of clinical applications. In this study, a novel Zn–2Ag–1.8Au–0.2V (wt.%) alloy (Zn–Ag–Au–V) was fabricated and investigated for use as a potential absorbable biocompatible material. Microstructural characterization indicated an effective grain-refining effect on the Zn alloy after a thermomechanical treatment. Compared to pure Zn, the Zn–Ag–Au–V alloy showed significantly enhanced mechanical properties, with a yield strength of 168 MPa, an ultimate tensile strength of 233 MPa, and an elongation of 17%. Immersion test indicated that the degradation rate of the Zn–Ag–Au–V alloy in Dulbecco’s phosphate buffered saline was approximately 7.34 ± 0.64 μm/year, thus being slightly lower than that of pure Zn. Biocompatibility tests with L929 and Saos-2 cells showed a moderate cytotoxicity, alloy extracts at 16.7%, and 10% concentration did not affect metabolic activity and cell proliferation. Plaque formation in vitro was reduced, the Zn–Ag–Au–V surface inhibited adhesion and biofilm formation by the early oral colonizer Streptococcus gordonii, indicating antibacterial properties of the alloy.

Recent Advances in Research on Antibacterial Metals and Alloys as Implant Materials

“…A binary Zn-4.0Ag alloy made by casting and proper treatment showed enhanced mechanical properties and effectively inhibited the adhesion and biofilm formation of S. gordonii . Similarly, the quaternary Zn-2Ag-1.8Au-0.2V alloy exhibited an antibacterial effect (Li et al, 2019a).…”

Appropriately adapted properties of hot-extruded Zn–0.5Cu–xFe alloys aimed for biodegradable guided bone regeneration membrane application

“…These species, mainly involved in postoperative infections after transoral surgeries, are proposed to reflect the oral environment [ [46] , [47] , [48] ]. Furthermore, S. gordonii and mixed oral bacteria were incubated and collected, as we previously reported in detail [ 46 , 49 ]. Briefly, mixed oral bacteria were freshly collected from a periodontally healthy volunteer after obtaining informed consent.…”

Advances on biodegradable zinc-silver-based alloys for biomedical applications

“…35 As the other major component of Zn-Ag-based alloys, Ag has been rarely studied on its cytotoxicity, which may be related to the fact that the release of silver in Zn-Ag alloy is mostly trivial and is below the detection threshold (<50 µg/L). 32,35 The LC50 of silver was reported to be 11.0 µM for tumor cells (MG-63) and 9.0 µM for macrophages (RAW 264.7). 47 The discrepancy between the actual released silver concentration and LC50 may indicate that the silver has little effect on biocompatibility in Zn-Ag alloys, just as reported previously that metallic and alloyed silver is neither genotoxic nor cytotoxic.…”