Early osteoimmunomodulatory effects of magnesium–calcium–zinc alloys

Abstract

Today, substantial attention is given to biomaterial strategies for bone regeneration, and among them, there is a growing interest in using immunomodulatory biomaterials. The ability of a biomaterial to induce neo vascularization and macrophage polarization is a major factor in defining its success. Magnesium (Mg)-based degradable alloys have attracted significant attention for bone regeneration owing to their biodegradability and potential for avoiding secondary removal surgeries. However, there is insufficient evidence in the literature regarding the early inflammatory responses to these alloys in vivo. In this study, we investigated the early body responses to Mg-0.45wt%Zn-0.45wt%Ca pin-shaped alloy (known as ZX00 alloy) in rat femora 2, 5, and 10 days after implantation. We used 3D micro computed tomography (µCT), histological, immunohistochemical, histomorphometrical, and small angle X-ray scattering (SAXS) analyses to study new bone formation, early macrophage polarization, neo vascularization, and bone quality at the implant bone interface. The expression of macrophage type 2 biological markers increased significantly after 10 days of Mg alloy implantation, indicating its potential in stimulating macrophage polarization. Our biomineralization results using µCT as well as histological stained sections did not indicate any statistically significant differences between different time points for both groups. The activity of alkaline phosphatase (ALP) and Runt-related transcription factor 2 (Runx 2) biological markers decreased significantly for Mg group, indicating less osteoblast activity. Generally, our results supported the potential of ZX00 alloy to enhance the expression of macrophage polarization in vivo; however, we could not observe any statistically significant changes regarding biomineralization.

In Vitro Monitoring of Magnesium-Based Implants Degradation by Surface Analysis and Optical Spectroscopy

“…However, no statistically significant difference was found for Ti treatment in the DMEM solution from Day 2 to Day 10. This behaviour was almost similar to the in vivo findings by Rahmati et al for Mg alloys [ 35 ]. Figure 7 A,B show the analysis of the weight loss and contact angle measurements, respectively.…”

“…Pure Mg has more variation as compared to the Mg alloy and Ti. The overall trend was in the following order: d5 > d2 > d0 > d10, which corresponded to the in vivo study that was performed on the same Mg alloy [ 35 ]. A hydrophobic textured surface has been reported to trap the surface gas layer, protecting against corrosion [ 45 ].…”

Osteocytes Influence on Bone Matrix Integrity Affects Biomechanical Competence at Bone-Implant Interface of Bioactive-Coated Titanium Implants in Rat Tibiae

“…The analyzer was kept at 150° and lambda plate was kept at 75° for all samples. Monochrome and colored images were taken using 10×, 20×, 40×, and oil immersion (100×) magnification as previously described [ 74 ].…”

Rationale for Processing of a Mg-Zn-Ca Alloy by Equal-Channel Angular Pressing for Use in Biodegradable Implants for Osteoreconstruction

“…Magnesium and its alloys are considered as potential candidates for orthopedic implants that can replace permanent metal implants based on titanium or stainless steel. The advantage of Mg alloys is their biodegradability and osteoconduction, in combination with sufficiently good mechanical properties [1,2]. In contrast with titanium or steel implants, magnesium alloys do not cause stress-shielding issues and are characterized by greater mechanical stability than polymer materials [3].…”

“…resistance of Mg-1%Zn-0.3%Ca measured by the PDP method (Ecorr-corrosion potential, Icorr-current density).StateEcorr, mV (vs SCE) Icorr, μA/cm2 …”