Enhanced Bioactivity of Mg–Nd–Zn–Zr Alloy Achieved with Nanoscale MgF₂ Surface for Vascular Stent Application

Abstract

Magnesium (Mg) alloys have revolutionized the application of temporary load-bearing implants as they meet both engineering and medical requirements. However, rapid degradation of Mg alloys under physiological conditions remains the major obstacle hindering the wider use of Mg-based implants. Here we developed a simple method of preparing a nanoscale MgF2 film on Mg-Nd-Zn-Zr (denoted as JDBM) alloy, aiming to reduce the corrosion rate as well as improve the biological response. The corrosion rate of JDBM alloy exposed to artificial plasma is reduced by ∼20% from 0.337 ± 0.021 to 0.269 ± 0.043 mm·y(-1) due to the protective effect of the MgF2 film with a uniform and dense physical structure. The in vitro cytocompatibility test of MgF2-coated JDBM using human umbilical vein endothelial cells indicates enhanced viability, growth, and proliferation as compared to the naked substrate, and the MgF2 film with a nanoscale flakelike feature of ∼200-300 nm presents a much more favorable environment for endothelial cell adhesion, proliferation, and alignment. Furthermore, the animal experiment via implantation of MgF2-coated JDBM stent to rabbit abdominal aorta confirms excellent tissue compatibility of the well re-endothelialized stent with no sign of thrombogenesis and restenosis in the stented vessel.

Effect of macrophages on in vitro corrosion behavior of magnesium alloy

“…23,24 Wang et al studied the corrosion of Mg alloy under dynamic fluid flow condition and found that the flow stress induced by fluid flow could accelerate the in vitro corrosion of Mg alloy. 25 Though the influences of Mg alloy on viability, proliferation, and function of cells have been extensively studied, [26][27][28] the converse question about the role of cells during Mg alloy corrosion has been barely examined. The infiltration of inflammatory cells and macrophage clusters was observed at the implantation site of Mg alloy implants both for vascular stent and orthopedic applications due to the host response.…”

Effects of Li on Microstructures, Mechanical, and Biocorrosion Properties of Biodegradable Mg94‐xZn2Y4Lix Alloys with Long Period Stacking Ordered Phase

“…The Nyquist plots of the three samples were similar except for the difference in the diameter of the loops, which consisted of one high frequency capacitance loop and one low frequency capacitance loop. The high‐frequency capacitive loop can be attributed to the charge transfer of the corrosion process . The capacitive loops for Mg 89 Zn 2 Y 4 Li 5 alloy exhibited a higher diameter in comparison with other two alloys.…”

Advances and Challenges of Biodegradable Implant Materials with a Focus on Magnesium-Alloys and Bacterial Infections

“…Vascular magnesium alloy stents with reduced corrosion rates have been shown to be mechanically stable for up to 6 months in animal experiments and were eventually evaluated in clinical trials [97][98][99][100][101][102][103]. Polymer-coated drug-eluting magnesium stents (Magmaris and DREAMS; Biotronik AG, 231, Bülach, Switzerland) were commercially offered and claimed to be resorbed to 95% within a year in clinical trials.…”