Biocompatibility Assessment of Zinc Alloys as a New Potential Material for Bioabsorbable Implants for Osteosynthesis

Abstract

In the last several years, zinc and its alloys have come into focus as bioabsorbable materials by qualifying themselves with an excellent corrosion rate, mechanical properties, anti-bacterial effects. and considerable biocompatibility. In this study, the biocompatibility of zinc–silver alloys containing 3.3 wt% silver (ZnAg3) was assessed by evaluating their cell viability, the proliferation rate, and the cell toxicity. Two alloys were investigated in which one was phosphated and the other was non-phosphated. The alloys were tested on human osteoblasts (hOb), which are, to a large extent, responsible for bone formation and healing processes. The performance of the phosphated alloy did not differ significantly from the non-phosphated alloy. The results showed a promising biocompatibility with hOb for both alloys equally in all conducted assays, qualifying ZnAg3 for further investigations such as in vivo studies.

Mechanical Properties and Corrosion Rate of ZnAg3 as a Novel Bioabsorbable Material for Osteosynthesis

“…Hagelstein et al [38] described a corrosion rate of 0.14 mm/year for ZnAg3 with an Ag content of 3.0 wt% manufactured by Limedion and Quadralux (Limedion GmbH, Mannheim, Germany; Quadralux e.K., Mannheim, Germany), which is slightly higher than the measured corrosion rate in this study. This circumstance might be due to the fact that the grain size of the ZnAg3 in this study was determined to be smaller at 5-10 µm and the Ag content was higher at 3.3 wt%, as previous investigations could show [47]. Thus, it is apparent that the grain size in fact impacts the corrosion rate.…”

“…Therefore, the extrusion process and the associated effects on grain size have an impact on the material properties. In this study, ZnAg3 manufactured by Limedion and Quadralux (Limedion GmbH, Mannheim, Germany; Quadralux e.K., Mannheim, Germany) showed a grain size of 5-10 µm after hot extrusion at 250-300 °C with an extrusion rate of 25:1 [47]. In comparison, Sikora-Jasinska et al [30] reported a UTS of 203 MPa, a YS of 157 MPa, and an elongation at fracture of approximately 34% for ZnAg2.5 with a grain size of 16 µm after hot extrusion at 250 °C with an extrusion rate of 14:1.…”

“…The zinc-silver alloy contained 3.3 wt% Ag and showed promising biocompatibility on human osteoblasts in previous investigations, which is why this alloy was selected for further investigations [47]. More details about the tested alloy can be found in a previously published paper characterizing the alloy [47]. The alloy in this study was not coated and did not receive any surface modifications.…”

“…has not yet been described in the literature with regard to its mechanical properties and may represent a novel material for osteosynthesis. The zinc-silver alloy contained 3.3 wt% Ag and showed promising biocompatibility on human osteoblasts in previous investigations, which is why this alloy was selected for further investigations [47]. More details about the tested alloy can be found in a previously published paper characterizing the alloy [47].…”